由“单独搭建Mybatis”到“Mybatis与Spring的整合/集成”

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由“单独搭建Mybatis”到“Mybatis与Spring的整合/集成”
在J2EE领域，Hibernate与Mybatis是大家常用的持久层框架，它们各有特点，在持久层框架中处于领导地位。

本文主要介绍Mybatis（对于较小型的系统，特别是报表较多的系统，个人偏向Mybatis），对于它，个人比较喜欢的是：
- 使用简单、方便；
- 支持的XML动态SQL的编写，方便浏览、修改，同时降低SQL与应用程序之间的耦合。
不喜欢的是：
- 出现错误时，调试不太方便
本文主要介绍Mybatis的搭建，是学习Mybatis过程后整理的札记，其中包括“单独搭建Mybaits”和常用的“Mybatis与Spring的整合”。

一、数据库的准备

因为Mybatis是持久层框架，毫无疑问，是需要操作数据库的。所以，在搭建之前，我们需要先创建一个简单的表。

SQL - DDL - Create Table
create table T_USER_TEST_1407 ( USERNAME VARCHAR2(255), PASSWORD VARCHAR2(255) )
插入一些数据，以作查询的测试。
insert into T_USER_TEST_1407 (USERNAME, PASSWORD) values ('nick', 'Optimistic,Confident,Love - 1');

insert into T_USER_TEST_1407 (USERNAME, PASSWORD) values ('nick', 'Optimistic,Confident,Love - 1');
二、单独搭建Mybaits

1）环境准备、版本说明

此工程使用JDK1.6 + mybatis-3.2.4 + Oracle11g。

新建一个Web工程，由于只构建Mybatis，只引用Mybatis和Oracle JDBC驱动包
- mybatis-3.2.4.jar
- ojdbc6.jar
2）程序的搭建

首先，我们将数据源等配置信息放在一个xml，让Mybatis可以根据这个信息去连接数据库、管理事务。

目前我们可只关注environments节点，此节点是用于配置数据源、事务管理的。

其他的节点，如typeAliases、mappers，是用于注册一些信息的，后面会陆续提到。

mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>


<typeAliases>
<typeAlias alias="user" type="com.nicchagil.mybatisonly.bean.User" />
</typeAliases>


<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="oracle.jdbc.driver.OracleDriver" />
<property name="url" value="jdbc:oracle:thin:@xxx.xxx.xxx.xxx:xxxx:xxxxxx" />
<property name="username" value="xxxx" />
<property name="password" value="xxxx" />
</dataSource>
</environment>
</environments>


<mappers>

<mapper resource="com/nicchagil/mybatisonly/mapper/sqlxml/UserMapper.xml" />
</mappers>

</configuration>

mybatis-config.xml

1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE configuration 3 PUBLIC "-//mybatis.org//DTD Config 3.0//EN" 4 "http://mybatis.org/dtd/mybatis-3-config.dtd"> 5 6 <configuration> 7 8  9 <typeAliases> 10 <typeAlias alias="user" type="com.nicchagil.mybatisonly.bean.User" /> 11 </typeAliases> 12 13  14 <environments default="development"> 15 <environment id="development"> 16 <transactionManager type="JDBC" /> 17 <dataSource type="POOLED"> 18 <property name="driver" value="oracle.jdbc.driver.OracleDriver" /> 19 <property name="url" value="jdbc:oracle:thin:@xxx.xxx.xxx.xxx:xxxx:xxxxxx" /> 20 <property name="username" value="xxxx" /> 21 <property name="password" value="xxxx" /> 22 </dataSource> 23 </environment> 24 </environments> 25 26  27 <mappers> 28  29 <mapper resource="com/nicchagil/mybatisonly/mapper/sqlxml/UserMapper.xml" /> 30 </mappers> 31 32 </configuration>
既然有了配置的xml，下一步就需要让Mybatis加载它了。
1. 首先以输入流的形式加载xml
2. 以“SqlSessionFactoryBuilder -> SqlSessionFactory -> SqlSession”的流程最后构建出SqlSession。
  
  SqlSession，顾名思义，是一次会话，是应用程序与数据库交互的会话，所以，其生命周期应在一次数据库连接之间，当然，此次数据库连接可以包含一次或多次数据库操作。
  
  SqlSessionFactory，顾名思义，是SqlSession的工厂类，用于产出SqlSession。我们知道，SqlSession主要用于数据库操作，而数据库操作又是贯穿于应用程序整个生命周期当中的，那么，"产出SqlSession"这个动作也应当贯穿于应用程序整个生命周期当中，所以，SqlSessionFactory的生命周期一般为应用程序的整个生命周期，一般为单例/static的形式存在。
  
  SqlSessionFactoryBuilder，由代码可见，其主要作用是从配置文件中获取配置信息，然后构建SqlSessionFactory，所以其生命周期可以是临时的，局部的。
3. 通过SqlSession获取UserMapper接口，再调用该接口的数据操纵方法。
Call
package com.nicchagil.mybatisonly;

import java.io.IOException;
import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import com.nicchagil.mybatisonly.bean.User;
import com.nicchagil.mybatisonly.mapper.UserMapper;

public class Call {

public static SqlSessionFactory sqlSessionFactory = null;

public static void main(String[] args) throws IOException {

// Query User
/*
kickStartMybatis();
queryUser("nick");
*/

// Inser User
kickStartMybatis();
insertUser("user004", "hello world.");

}

public static void kickStartMybatis() throws IOException {
String resource = "com/nicchagil/mybatisonly/mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
}

/**
* Query User
* @param username
* @return
*/
public static User queryUser(String username) {

User user = null;
SqlSession session = sqlSessionFactory.openSession();
try {

/* Un-recommended Method */
/*
user = (User)session.selectOne("com.nicchagil.mybatisonly.mapper.UserMapper.queryUser", username);
*/

/* Recommended Method */
UserMapper userMapper = session.getMapper(UserMapper.class);
user = userMapper.queryUser(username);

System.out.println("username - " + user.getUsername() + " , password - " + user.getPassword());

} finally {
session.close();
}

return user;
}

/**
* Insert User
* @param username
* @param password
*/
public static void insertUser(String username, String password) {

SqlSession session = sqlSessionFactory.openSession();

try {

UserMapper userMapper = session.getMapper(UserMapper.class);

User user = new User();
user.setUsername(username);
user.setPassword(password);

userMapper.insertUser(user);

// Flushes batch statements and commits database connection.
// Note that database connection will not be committed if no updates/deletes/inserts were called.
session.commit();

System.out.println("username - " + user.getUsername() + " , password - " + user.getPassword());

} catch (Exception e) {
session.rollback();
e.printStackTrace();

//TODO Print the exception logs
//TODO Prompts fail to execute for user

} finally {
session.close();
}

}

/**
* Insert User
* @param username
* @param password
*/
public static void insertUserBySQL(String username, String password) {

SqlSession session = sqlSessionFactory.openSession();

try {

User user = new User();
user.setUsername(username);
user.setPassword(password);

session.insert("com.nicchagil.mybatisonly.mapper.UserMapper.insertUser", user);

// Flushes batch statements and commits database connection.
// Note that database connection will not be committed if no updates/deletes/inserts were called.
session.commit();

} catch (Exception e) {
session.rollback();
e.printStackTrace();

//TODO Print the exception logs
//TODO Prompts fail to execute for user

} finally {
session.close();
}

}

}

Call

package com.nicchagil.mybatisonly; import java.io.IOException; import java.io.InputStream; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; import com.nicchagil.mybatisonly.bean.User; import com.nicchagil.mybatisonly.mapper.UserMapper; public class Call { public static SqlSessionFactory sqlSessionFactory = null; public static void main(String[] args) throws IOException { // Query User /* kickStartMybatis(); queryUser("nick"); */ // Inser User kickStartMybatis(); insertUser("user004", "hello world."); } public static void kickStartMybatis() throws IOException { String resource = "com/nicchagil/mybatisonly/mybatis-config.xml"; InputStream inputStream = Resources.getResourceAsStream(resource); sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); } /** * Query User * @param username * @return */ public static User queryUser(String username) { User user = null; SqlSession session = sqlSessionFactory.openSession(); try { /* Un-recommended Method */ /* user = (User)session.selectOne("com.nicchagil.mybatisonly.mapper.UserMapper.queryUser", username); */ /* Recommended Method */ UserMapper userMapper = session.getMapper(UserMapper.class); user = userMapper.queryUser(username); System.out.println("username - " + user.getUsername() + " , password - " + user.getPassword()); } finally { session.close(); } return user; } /** * Insert User * @param username * @param password */ public static void insertUser(String username, String password) { SqlSession session = sqlSessionFactory.openSession(); try { UserMapper userMapper = session.getMapper(UserMapper.class); User user = new User(); user.setUsername(username); user.setPassword(password); userMapper.insertUser(user); // Flushes batch statements and commits database connection. // Note that database connection will not be committed if no updates/deletes/inserts were called. session.commit(); System.out.println("username - " + user.getUsername() + " , password - " + user.getPassword()); } catch (Exception e) { session.rollback(); e.printStackTrace(); //TODO Print the exception logs //TODO Prompts fail to execute for user } finally { session.close(); } } /** * Insert User * @param username * @param password */ public static void insertUserBySQL(String username, String password) { SqlSession session = sqlSessionFactory.openSession(); try { User user = new User(); user.setUsername(username); user.setPassword(password); session.insert("com.nicchagil.mybatisonly.mapper.UserMapper.insertUser", user); // Flushes batch statements and commits database connection. // Note that database connection will not be committed if no updates/deletes/inserts were called. session.commit(); } catch (Exception e) { session.rollback(); e.printStackTrace(); //TODO Print the exception logs //TODO Prompts fail to execute for user } finally { session.close(); } } }
UserMapper是一个DAO的接口，是定义作哪些数据库操作的。

UserMapper.java
package com.nicchagil.mybatisonly.mapper;

import com.nicchagil.mybatisonly.bean.User;

public interface UserMapper {

public User queryUser(String username);

}

1 package com.nicchagil.mybatisonly.mapper; 2 3 import com.nicchagil.mybatisonly.bean.User; 4 5 public interface UserMapper { 6 7 public User queryUser(String username); 8 9 }
UserMapper只是供调用的接口，那么具体的实现逻辑在哪里呢？

我们可见UserMaper.xml，它定义的SQL就是用于定义UserMapper接口的实现。我们需在mybatis-config.xml注册UserMaper.xml，可见mybatis-config.xml的mappers节点。
- 我们可以看到id为queryUser，与接口的方法名对应；
- SQL我们很熟悉了，就是一个简单的SQL，而#{username}，就是接口方法的入参；
- resultType为"user"，这个user是一个别名，具体对应com.nicchagil.mybatisonly.bean.User这个类，我们可以看到在mybatis-config.xml文件的typeAliases节点中已经注册它们的映射关系。
UserMapper.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.nicchagil.mybatisonly.mapper.UserMapper">

<select id="queryUser" resultType="user">
select * from t_user_test_1407 t where t.username = #{username}
</select>

<insert id="insertUser" parameterType="user">
INSERT INTO t_user_test_1407 T (T.USERNAME, T.PASSWORD) VALUES (#{username}, #{password})
</insert>

</mapper>

UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.nicchagil.mybatisonly.mapper.UserMapper"> <select id="queryUser" resultType="user"> select * from t_user_test_1407 t where t.username = #{username} </select> <insert id="insertUser" parameterType="user"> INSERT INTO t_user_test_1407 T (T.USERNAME, T.PASSWORD) VALUES (#{username}, #{password}) </insert> </mapper>
而com.nicchagil.mybatisonly.bean.User是实体类，用于装载数据。

User.java

package com.nicchagil.mybatisonly.bean;

public class User {

private String username;
private String password;

public String getUsername() {
return username;
}

public void setUsername(String username) {
this.username = username;
}

public String getPassword() {
return password;
}

public void setPassword(String password) {
this.password = password;
}

@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result
+ ((password == null) ? 0 : password.hashCode());
result = prime * result
+ ((username == null) ? 0 : username.hashCode());
return result;
}

@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
User other = (User) obj;
if (password == null) {
if (other.password != null)
return false;
} else if (!password.equals(other.password))
return false;
if (username == null) {
if (other.username != null)
return false;
} else if (!username.equals(other.username))
return false;
return true;
}

}

User.java
1 package com.nicchagil.mybatisonly.bean; 2 3 public class User { 4 5 private String username; 6 private String password; 7 8 public String getUsername() { 9 return username; 10 } 11 12 public void setUsername(String username) { 13 this.username = username; 14 } 15 16 public String getPassword() { 17 return password; 18 } 19 20 public void setPassword(String password) { 21 this.password = password; 22 } 23 24 @Override 25 public int hashCode() { 26 final int prime = 31; 27 int result = 1; 28 result = prime * result 29 + ((password == null) ? 0 : password.hashCode()); 30 result = prime * result 31 + ((username == null) ? 0 : username.hashCode()); 32 return result; 33 } 34 35 @Override 36 public boolean equals(Object obj) { 37 if (this == obj) 38 return true; 39 if (obj == null) 40 return false; 41 if (getClass() != obj.getClass()) 42 return false; 43 User other = (User) obj; 44 if (password == null) { 45 if (other.password != null) 46 return false; 47 } else if (!password.equals(other.password)) 48 return false; 49 if (username == null) { 50 if (other.username != null) 51 return false; 52 } else if (!username.equals(other.username)) 53 return false; 54 return true; 55 } 56 57 }
最后，我们运行Call.java，将能成功查询、插入数据库。我们可通过打印的信息和查询数据库，以查看是否成功查询、插入数据。

3）事务说明

对于数据库有写操作的应用程序，一般来说，事务是不可或缺的一部分。因为未使用其他框架，这里使用编程式事务，即使用SqlSession.commit()和SqlSession.rollback()方法，可见Call.java。
- 由于本程序对事务有异常回滚的要求，所以，需要获取非自动提交的SqlSession
- 如程序执行正常，则最后执行session.commit()以提交事务。
  
  session.commit()有个需注意的地方，参考其如下注释，即如果当前会话中不涉及updates/deletes/insert等写数动作则不提交事务。所以，如果要触发Mybatis提交事务，就需执行明确的触发动作，如“执行session.insert(...)方法”或“执行对应的SQL Mapper配置中的insert、update、delete等标签”等操作。（本人曾尝试在SQL Mapper配置中用select标签包含INSERT的SQL，使用SqlSession.commit()后，执行正常，但没有提交事务，可见并未触发，所以，需规范使用标签）。如需强制提交，可用SqlSession.commit(boolean)。
  
  Flushes batch statements and commits database connection. Note that database connection will not be committed if no updates/deletes/inserts were called. To force the commit call SqlSession.commit(boolean)
- 如程序执行异常，则回滚事务，session.rollback()
单独搭建Mybaits完毕！

二、 Mybatis与Spring的整合

一个项目中，单独使用Mybatis的情况并不多；更多的情况下，我们需要将Mybatis与其他框架进行整合，以便更好地使用。比如Mybatis + Spring，就是一个流行的整合组合。

1）环境准备、版本说明

本次用Mybatis3 + Spring3进行整合。注意，并不包含MVC框架的配置，因为本文的目的是学习Mybatis，所以尽量不引用其他框架，以避免影响代码的理解。

需引入的类库详情如下:

MVN dependencies
<dependencies>

<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>3.2.10.RELEASE</version>
</dependency>

<dependency>
<groupId>org.springframework.webflow</groupId>
<artifactId>spring-webflow</artifactId>
<version>2.4.0.RELEASE</version>
</dependency>

<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-oracle</artifactId>
<version>1.0.0.RELEASE</version>
</dependency>

<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.2.4</version>
</dependency>

<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>1.2.2</version>
</dependency>

</dependencies>

<dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>3.8.1</version> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>3.2.10.RELEASE</version> </dependency> <dependency> <groupId>org.springframework.webflow</groupId> <artifactId>spring-webflow</artifactId> <version>2.4.0.RELEASE</version> </dependency> <dependency> <groupId>org.springframework.data</groupId> <artifactId>spring-data-oracle</artifactId> <version>1.0.0.RELEASE</version> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.2.4</version> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis-spring</artifactId> <version>1.2.2</version> </dependency> </dependencies>
2）程序的搭建

首先，我们在Spring中配置关于Mybatis数据源的信息。

这里以applicationContext-mybatis.xml来体现，配置了如下信息：
- 注册数据源，常见的有JDBC或JNDI，根据具体情况择一。
- 注册sqlSessionFactory
  
  sqlSessionFactory是用来生产sqlSession以操作数据库的，所以，需指定sqlSessionFactory所引用的数据源
  
  指定相应的SQL Mapper文件在哪里。我们自命名“_mapper后缀的xml文件”，主要用来定义SQL；“_resultmap后缀的xml文件”，则主要用来定义DB字段与应用程序实体属性的映射。
  
  指定相应的应用程序实体在哪里，并自动注册不包含package名的别名
- 在哪些package下扫描Mapper接口，即DAO接口
applicationContext-mybatis.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">





<bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName">
<value>JNDI_TEST_DB</value>
</property>
</bean>

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="mapperLocations">
<list>
<value>classpath:com/nicchagil/mybatis3spring3intg/mapper/sqlxml/*_mapper.xml</value>
<value>classpath:com/nicchagil/mybatis3spring3intg/bean/resultmapxml/*_resultmap.xml</value>
</list>
</property>
<property name="typeAliasesPackage" value="com.nicchagil.mybatis3spring3intg.bean" />
</bean>

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.nicchagil.mybatis3spring3intg.mapper" />
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" />
</bean>

</beans>

applicationContext-mybatis.xml

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">    <bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryBean"> <property name="jndiName"> <value>JNDI_TEST_DB</value> </property> </bean> <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> <property name="dataSource" ref="dataSource" /> <property name="mapperLocations"> <list> <value>classpath:com/nicchagil/mybatis3spring3intg/mapper/sqlxml/*_mapper.xml</value> <value>classpath:com/nicchagil/mybatis3spring3intg/bean/resultmapxml/*_resultmap.xml</value> </list> </property> <property name="typeAliasesPackage" value="com.nicchagil.mybatis3spring3intg.bean" /> </bean> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="basePackage" value="com.nicchagil.mybatis3spring3intg.mapper" /> <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory" /> </bean> </beans>
除了Mybatis的信息，还有一些Spring的信息需要配置：
- 根据注解自动扫描并注册bean
- Spring的声明式事务管理（用以替代上一章节的“编程式事务”）
- 由于本程序没有集成MVC框架，在Servlet是通过Spring编程式地获得Spring管理的bean，所以这里注册一个Spring的工具类。（使用了MVC框架并将框架交由Spring IOC容器管理的，可忽视此点配置）
applicationContext.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-3.0.xsd">

<context:component-scan base-package="com.nicchagil.mybatis3spring3intg" />


<tx:annotation-driven transaction-manager="transactionManager" />
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource" />
</bean>

<bean id="SpringContextUtil" class="com.nicchagil.util.SpringContextUtil"/>

</beans>

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd"> <context:component-scan base-package="com.nicchagil.mybatis3spring3intg" />  <tx:annotation-driven transaction-manager="transactionManager" /> <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <property name="dataSource" ref="dataSource" /> </bean> <bean id="SpringContextUtil" class="com.nicchagil.util.SpringContextUtil"/> </beans>
众所周知，以上是Spring的配置文件，那么我们需要告诉应用程序“这些配置文件在哪里”，所以我们需要在web.xml中告诉应用程序。另外，此web.xml注册了一个Servlet，用于接收页面的请求。

web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<display-name>mybatis3spring3Intg</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath*:config/applicationContext*.xml</param-value>
</context-param>
<servlet>
<description></description>
<display-name>UserServlet</display-name>
<servlet-name>UserServlet</servlet-name>
<servlet-class>com.nicchagil.mybatis3spring3intg.servlet.UserServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UserServlet</servlet-name>
<url-pattern>/UserServlet</url-pattern>
</servlet-mapping>
</web-app>

web.xml

<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5"> <display-name>mybatis3spring3Intg</display-name> <welcome-file-list> <welcome-file>index.html</welcome-file> </welcome-file-list> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath*:config/applicationContext*.xml</param-value> </context-param> <servlet> <description></description> <display-name>UserServlet</display-name> <servlet-name>UserServlet</servlet-name> <servlet-class>com.nicchagil.mybatis3spring3intg.servlet.UserServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>UserServlet</servlet-name> <url-pattern>/UserServlet</url-pattern> </servlet-mapping> </web-app>
我们还需要定义Mapper的接口，即DAO接口。此处的Mapper的接口，我们已经在applicationContext-mybatis.xml中注册为指定路径下自动扫描。

UserMapper.java
package com.nicchagil.mybatis3spring3intg.mapper;

import com.nicchagil.mybatis3spring3intg.bean.User;

public interface UserMapper {

public User find(String username);

public void save(User user);

}

UserMapper.java

package com.nicchagil.mybatis3spring3intg.mapper; import com.nicchagil.mybatis3spring3intg.bean.User; public interface UserMapper { public User find(String username); public void save(User user); }
而Mapper的实现是如何的呢？

Mybatis会帮我们实现，我们只需要通过user_mapper.xml文件告诉Mybatis对应的SQL，此处的mapper文件，已经在applicationContext-mybatis.xml中注册为指定路径下自动扫描。

user_mapper.xml
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.nicchagil.mybatis3spring3intg.mapper.UserMapper"> <select id="find" resultType="user" resultMap="userResultMap"> select * from t_user_test_1407 t where t.username = #{username} </select> <insert id="save" parameterType="user"> INSERT INTO t_user_test_1407 T (T.USERNAME, T.PASSWORD) VALUES (#{username}, #{password}) </insert> </mapper>

<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.nicchagil.mybatis3spring3intg.mapper.UserMapper"> <select id="find" resultType="user" resultMap="userResultMap"> select * from t_user_test_1407 t where t.username = #{username} </select> <insert id="save" parameterType="user"> INSERT INTO t_user_test_1407 T (T.USERNAME, T.PASSWORD) VALUES (#{username}, #{password}) </insert> </mapper>
可以看到，Mapper和SQL配置文件中都引用到了实体类，我们也需要定义。此处的实体类，已经在applicationContext-mybatis.xml中注册为指定路径下自动扫描。

User.java
package com.nicchagil.mybatis3spring3intg.bean;

public class User {

private String username;
private String password;
private String childhoodName;

public String getUsername() {
return username;
}

public void setUsername(String username) {
this.username = username;
}

public String getPassword() {
return password;
}

public void setPassword(String password) {
this.password = password;
}

public String getChildhoodName() {
return childhoodName;
}

public void setChildhoodName(String childhoodName) {
this.childhoodName = childhoodName;
}

@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result
+ ((childhoodName == null) ? 0 : childhoodName.hashCode());
result = prime * result
+ ((password == null) ? 0 : password.hashCode());
result = prime * result
+ ((username == null) ? 0 : username.hashCode());
return result;
}

@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
User other = (User) obj;
if (childhoodName == null) {
if (other.childhoodName != null)
return false;
} else if (!childhoodName.equals(other.childhoodName))
return false;
if (password == null) {
if (other.password != null)
return false;
} else if (!password.equals(other.password))
return false;
if (username == null) {
if (other.username != null)
return false;
} else if (!username.equals(other.username))
return false;
return true;
}

}

User.java

package com.nicchagil.mybatis3spring3intg.bean; public class User { private String username; private String password; private String childhoodName; public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getChildhoodName() { return childhoodName; } public void setChildhoodName(String childhoodName) { this.childhoodName = childhoodName; } @Override public int hashCode() { final int prime = 31; int result = 1; result = prime * result + ((childhoodName == null) ? 0 : childhoodName.hashCode()); result = prime * result + ((password == null) ? 0 : password.hashCode()); result = prime * result + ((username == null) ? 0 : username.hashCode()); return result; } @Override public boolean equals(Object obj) { if (this == obj) return true; if (obj == null) return false; if (getClass() != obj.getClass()) return false; User other = (User) obj; if (childhoodName == null) { if (other.childhoodName != null) return false; } else if (!childhoodName.equals(other.childhoodName)) return false; if (password == null) { if (other.password != null) return false; } else if (!password.equals(other.password)) return false; if (username == null) { if (other.username != null) return false; } else if (!username.equals(other.username)) return false; return true; } }
实体的属性与DB的字段之间的映射/匹配，我们需要定义一下。此处的resultmap.xml文件已经在applicationContext-mybatis.xml中注册为指定路径下自动扫描。

user_resultmap.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.nicchagil.mybatis3spring3intg.mapper.UserMapper">
<resultMap type="user" id="userResultMap">
<result property="username" column="USERNAME" />
<result property="password" column="PASSWORD" />
<result property="childhoodName" column="USERNAME" />
</resultMap>
</mapper>

user_resultmap.xml

<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.nicchagil.mybatis3spring3intg.mapper.UserMapper"> <resultMap type="user" id="userResultMap"> <result property="username" column="USERNAME" /> <result property="password" column="PASSWORD" /> <result property="childhoodName" column="USERNAME" /> </resultMap> </mapper>
完成了DAO，那么接着写Service。

首先一个Service的接口。

UserService.java
package com.nicchagil.mybatis3spring3intg.service;

import com.nicchagil.mybatis3spring3intg.bean.User;

public interface UserService {

public User query(String username);

public void save(User user);

public void testTransaction(User user1, User user2);

}

UserService.java

package com.nicchagil.mybatis3spring3intg.service; import com.nicchagil.mybatis3spring3intg.bean.User; public interface UserService { public User query(String username); public void save(User user); public void testTransaction(User user1, User user2); }
Service的实现类如下，这里只简单地测试查询、保存、事务是否能正常处理。

UserServiceImpl.java

package com.nicchagil.mybatis3spring3intg.service.impl;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.nicchagil.mybatis3spring3intg.bean.User;
import com.nicchagil.mybatis3spring3intg.mapper.UserMapper;
import com.nicchagil.mybatis3spring3intg.service.UserService;

@Service
public class UserServiceImpl implements UserService {

@Autowired
private UserMapper mapper;

@Override
public User query(String username) {
return mapper.find(username);
}

@Override
public void save(User user) {
mapper.save(user);
}

@Override
@Transactional
public void testTransaction(User user1, User user2) {
mapper.save(user1);

// Code a NullPointerException to test transaction setting
String str = null;
str.charAt(0);

mapper.save(user2);
}

}

UserServiceImpl.java

由于没有整合MVC框架，此处由一个Servlet(此Servlet已于web.xml中注册）获取页面请求并调用Service，

那么如何在Servlet中获得Spring IOC管理下Service的bean呢？这里借助SpringContextUtil（implements ApplicationContextAware），此SpringContextUtil于以上提及的applicationContext.xml中注册。

UserServlet.java
package com.nicchagil.mybatis3spring3intg.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.nicchagil.mybatis3spring3intg.bean.User;
import com.nicchagil.mybatis3spring3intg.service.UserService;
import com.nicchagil.util.SpringContextUtil;

/**
* Servlet implementation class UserServlet
*/
public class UserServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#HttpServlet()
*/
public UserServlet() {
super();
// TODO Auto-generated constructor stub
}

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}

/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

String action = request.getParameter("action");

UserService service = (UserService)SpringContextUtil.getBean("userServiceImpl");

if ("find".equals(action)) {
User user = service.query(request.getParameter("username"));
System.out.println(user.getUsername() + " - " + user.getPassword() + " - " + user.getChildhoodName());

}

if ("save".equals(action)) {
User user = new User();
user.setUsername(request.getParameter("username"));
user.setPassword(request.getParameter("password"));

service.save(user);
System.out.println(user.getUsername() + " - " + user.getPassword());

}

if ("testTransaction".equals(action)) {
User user1 = new User();
user1.setUsername(request.getParameter("username"));
user1.setPassword(request.getParameter("password"));

User user2 = new User();
user2.setUsername(request.getParameter("username") + " - Double");
user2.setPassword(request.getParameter("password") + " - Double");

service.testTransaction(user1, user2);
System.out.println(user1.getUsername() + " - " + user1.getPassword());
System.out.println(user2.getUsername() + " - " + user2.getPassword());

}

}

}

UserServlet.java

package com.nicchagil.mybatis3spring3intg.servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import com.nicchagil.mybatis3spring3intg.bean.User; import com.nicchagil.mybatis3spring3intg.service.UserService; import com.nicchagil.util.SpringContextUtil; /** * Servlet implementation class UserServlet */ public class UserServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public UserServlet() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String action = request.getParameter("action"); UserService service = (UserService)SpringContextUtil.getBean("userServiceImpl"); if ("find".equals(action)) { User user = service.query(request.getParameter("username")); System.out.println(user.getUsername() + " - " + user.getPassword() + " - " + user.getChildhoodName()); } if ("save".equals(action)) { User user = new User(); user.setUsername(request.getParameter("username")); user.setPassword(request.getParameter("password")); service.save(user); System.out.println(user.getUsername() + " - " + user.getPassword()); } if ("testTransaction".equals(action)) { User user1 = new User(); user1.setUsername(request.getParameter("username")); user1.setPassword(request.getParameter("password")); User user2 = new User(); user2.setUsername(request.getParameter("username") + " - Double"); user2.setPassword(request.getParameter("password") + " - Double"); service.testTransaction(user1, user2); System.out.println(user1.getUsername() + " - " + user1.getPassword()); System.out.println(user2.getUsername() + " - " + user2.getPassword()); } } }
SpringContextUtil.java
package com.nicchagil.util;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;

public class SpringContextUtil implements ApplicationContextAware {

private static ApplicationContext applicationContext = null;

@Override
public void setApplicationContext(ApplicationContext ac)
throws BeansException {
applicationContext = ac;

}

public static ApplicationContext getApplicationContext() {
return applicationContext;
}

public static Object getBean(String beanName) {
return applicationContext.getBean(beanName);
}

public static boolean containsBean(String beanName) {
return applicationContext.containsBean(beanName);
}

}

SpringContextUtil.java

package com.nicchagil.util; import org.springframework.beans.BeansException; import org.springframework.context.ApplicationContext; import org.springframework.context.ApplicationContextAware; public class SpringContextUtil implements ApplicationContextAware { private static ApplicationContext applicationContext = null; @Override public void setApplicationContext(ApplicationContext ac) throws BeansException { applicationContext = ac; } public static ApplicationContext getApplicationContext() { return applicationContext; } public static Object getBean(String beanName) { return applicationContext.getBean(beanName); } public static boolean containsBean(String beanName) { return applicationContext.containsBean(beanName); } }
几乎大功告成。

这里写了些触发测试的页面，执行结果可通过“查看控制台”或“查询数据库”获得。哈哈！~~

导航页

index.html
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>

<a href="find.html">find</a>
<br/>
<a href="save.html">save</a>
<br/>
<a href="testTransaction.html">testTransaction</a>

</body>
</html>

index.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Insert title here</title> </head> <body> <a href="find.html">find</a> <br/> <a href="save.html">save</a> <br/> <a href="testTransaction.html">testTransaction</a> </body> </html>
输入username查询记录的触发页面

find.html
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>

<form action="UserServlet">
<input type="hidden" name="action" value="find">
<input type="text" name="username">
<input type="submit">
</form>

</body>
</html>

find.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Insert title here</title> </head> <body> <form action="UserServlet"> <input type="hidden" name="action" value="find"> <input type="text" name="username"> <input type="submit"> </form> </body> </html>
保存页面

save.html
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<body>

<form action="UserServlet">
<input type="hidden" name="action" value="save">
<input type="text" name="username">
<input type="password" name="password">
<input type="submit">
</form>

</body>

</body>
</html>

save.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Insert title here</title> </head> <body> <body> <form action="UserServlet"> <input type="hidden" name="action" value="save"> <input type="text" name="username"> <input type="password" name="password"> <input type="submit"> </form> </body> </body> </html>
测试事务的触发页面

testTransaction.html
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<body>

<form action="UserServlet">
<input type="hidden" name="action" value="testTransaction">
<input type="text" name="username">
<input type="password" name="password">
<input type="submit">
</form>

</body>

</body>
</html>

testTransaction.html

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Insert title here</title> </head> <body> <body> <form action="UserServlet"> <input type="hidden" name="action" value="testTransaction"> <input type="text" name="username"> <input type="password" name="password"> <input type="submit"> </form> </body> </body> </html>
大功告成！！

分享于：

https://github.com/nicchagil/mybatis3spring3Intg/tree/mybatis3spring3Intg_branch_initialization
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原文地址：https://www.cnblogs.com/telwanggs/p/5403165.html