1.Parent引入及pom配置
首先，如果要支持mybatis，那么我们就应该引入mybatis的starter。同时，由于连接本身还需要用jdbc的connetor和连接池，所以一并需要引入这些依赖。如下是一个完整的的最简pom，
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<packaging>war</packaging>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.3.RELEASE</version>
</parent>
<name>testboot01</name>
<groupId>com.zuikc</groupId>
<artifactId>testboot01</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<!--jsp支持, servlet 依赖. -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
</dependency>
<!-- tomcat 的支持.-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</dependency>
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>org.apache.tomcat</groupId>
<artifactId>tomcat-dbcp</artifactId>
<version>7.0.47</version>
</dependency>
<dependency>
<groupId>org.apache.tomcat</groupId>
<artifactId>tomcat-dbcp</artifactId>
<version>7.0.47</version>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
2.配置初始化
首先我们需要将数据库连接配置到文件中，比如prop.properties，
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test01?useUnicode=true&characterEncoding=utf8
jdbc.username=root
jdbc.password=root
jdbc.maxActive=2335
jdbc.maxIdel=120
jdbc.maxWait=100
然后，用java配置的方式将其引入到代码中，创建DataSourceConfiguration，
package com.zuikc.config;
import org.apache.tomcat.dbcp.dbcp.BasicDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
@Configuration
//这个注解导入刚才增加的jdbc配置文件
@PropertySource("classpath:prop.properties")
public class DataSourceConfiguration {
@Value("${jdbc.driver}")
private String driver;
@Value("${jdbc.url}")
private String url;
@Value("${jdbc.username}")
private String username;
@Value("${jdbc.password}")
private String password;
@Value("${jdbc.maxActive}")
private int maxActive;
@Value("${jdbc.maxIdel}")
private int maxIdel;
@Value("${jdbc.maxWait}")
private long maxWait;
@Bean
public BasicDataSource dataSource(){
BasicDataSource dataSource = new BasicDataSource();
dataSource.setDriverClassName(driver);
dataSource.setUrl(url);
dataSource.setUsername(username);
dataSource.setPassword(password);
dataSource.setMaxActive(maxActive);
dataSource.setMaxIdle(maxIdel);
dataSource.setMaxWait(maxWait);
dataSource.setValidationQuery("SELECT 1");
dataSource.setTestOnBorrow(true);
return dataSource;
}
}
接着，增加mybatis配置，
package com.zuikc.config;
import javax.sql.DataSource;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.SqlSessionTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.transaction.annotation.TransactionManagementConfigurer;
@Configuration
//加上这个注解，使得支持事务
@EnableTransactionManagement
public class MyBatisConfig implements TransactionManagementConfigurer {
@Autowired
private DataSource dataSource;
@Override
public PlatformTransactionManager annotationDrivenTransactionManager() {
return new DataSourceTransactionManager(dataSource);
}
@Bean(name = "sqlSessionFactory")
public SqlSessionFactory sqlSessionFactoryBean() {
SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
bean.setDataSource(dataSource);
try {
return bean.getObject();
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
@Bean
public SqlSessionTemplate sqlSessionTemplate(SqlSessionFactory sqlSessionFactory) {
return new SqlSessionTemplate(sqlSessionFactory);
}
}
注意上面的sqlSessionFactory这个bean。
然后需要配置MyBatis配置文件的路径，这个配置需要与上面的配置分开来写，因为它们有着一个先后顺序，
package com.zuikc.config;
import org.mybatis.spring.mapper.MapperScannerConfigurer;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
// 因为这个对象的扫描，需要在MyBatisConfig的后面注入，所以加上下面的注解
@AutoConfigureAfter(MyBatisConfig.class)
public class MyBatisMapperScannerConfig {
@Bean
public MapperScannerConfigurer mapperScannerConfigurer() {
MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();
//获取之前注入的beanName为sqlSessionFactory的对象
mapperScannerConfigurer.setSqlSessionFactoryBeanName("sqlSessionFactory");
//指定xml配置文件的路径
mapperScannerConfigurer.setBasePackage("com.zuikc.dao");
return mapperScannerConfigurer;
}
}
3.三层架构
先创建最底层的dao接口，如下：
package com.zuikc.dao;
import java.util.List;
import java.util.Map;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
@Mapper
public interface TestDao {
@Select("SELECT * FROM tbl_user;")
public List<Map<String,Object>> find();
}
接着创建service，
package com.zuikc.service;
import com.zuikc.dao.TestDao;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
import java.util.List;
import java.util.Map;
@Service
public class TestService {
@Resource
TestDao dao;
public List<Map<String,Object>> find(){
List<Map<String,Object>> users = dao.find();
return users;
}
}
然后是controller，
package com.zuikc.controller;
import com.zuikc.dao.TestDao;
import com.zuikc.service.TestService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import javax.annotation.Resource;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.Map;
@Controller
public class StudentController {
@Autowired
TestService service;
@RequestMapping(value = {"test01"})
public String view(Map<String, Object> map) {
List<Map<String,Object>> users = service.find();
for (Map<String, Object> user : users) {
for (Map.Entry<String, Object> entry : user.entrySet()) {
System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
}
}
System.out.println(users.size());
map.put("name", "zuikc.com");
map.put("date", new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));
return "views/test01";
}
}
经过上面的创建之后，我们的代码结构是这样的，
执行之，
注意了，如果你已经忘记了如何启动MySQL，那么，下面就是命令哦：
sudo bin/mysqld_safe --user=mysql &
4.事务支持
第一步，导入JDBC依赖，
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
注意，有了这个依赖，SpringBoot会自动注入DataSourceTransactionManager。
接着，直接在Service中添加@Transactional注解就能支持事务啦。本文不再赘述，大家自己尝试一下吧。
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