1、SSM框架整合
1.1、 环境需求
- IDEA
- MySQL 5.7.XX
- Tomcat 9
- Maven 3.6
1.2、SSM 项目基础结构
1.2.1、Mavem 项目建立
新建一个普通的Maven项目即可
1.2.1.1、 项目依赖
<dependencies>
<!-- JSON 解析-->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.12.4</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.20</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13.2</version>
<scope>test</scope>
</dependency>
<!-- java jsp-->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
<version>2.1</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<!-- Mysql-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.47</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.7</version>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>2.0.6</version>
</dependency>
<!-- 数据源-->
<dependency>
<groupId>com.mchange</groupId>
<artifactId>c3p0</artifactId>
<version>0.9.5.5</version>
</dependency>
<!-- Spring-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.3.7</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.3.9</version>
</dependency>
</dependencies>
1.2.1.2、静态资源导出
<build>
<!-- 修改Maven工程的 JDK版本 ：1.8 -->
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.8.1</version>
<configuration>
<target>1.8</target>
<source>1.8</source>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
</plugins>
<!-- 解决静态资源导出-->
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
</resources>
</build>
1.2.1.3、数据库
CREATE DATABASE `ssmbuild`;
USE `ssmbuild`;
DROP TABLE IF EXISTS `books`;
CREATE TABLE `books` (
`bookID` INT(10) NOT NULL AUTO_INCREMENT COMMENT '书id',
`bookName` VARCHAR(100) NOT NULL COMMENT '书名',
`bookCounts` INT(11) NOT NULL COMMENT '数量',
`detail` VARCHAR(200) NOT NULL COMMENT '描述',
KEY `bookID` (`bookID`)
) ENGINE=INNODB DEFAULT CHARSET=utf8
INSERT INTO `books`(`bookID`,`bookName`,`bookCounts`,`detail`)VALUES
(1,'Java',1,'从入门到放弃'),
(2,'MySQL',10,'从删库到跑路'),
(3,'Linux',5,'从进门到进牢');
1.2.1.4、applicationContet.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
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.xsd">
<import resource="classpath:spring-dao.xml"/>
<import resource="classpath:spring-service.xml"/>
<import resource="classpath:spring-mvc.xml"/>
</beans>
1.3、Mybatis层
database.properties
jdbc.driver=com.mysql.jdbc.Driver
# 如果使用的 Mysql8.0+，增加时区配置
jdbc.url=jdbc:mysql://localhost:3306/ssmbuild?useSSL=false&useUnicode=true&characterEncoding=UTF-8
jdbc.username=root
jdbc.password=123456
1.3.1、spring-dao.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
<!-- 关联数据库文件 database -->
<context:property-placeholder location="classpath:database.properties"/>
<!-- c3p0 连接池-->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="${jdbc.driver}"/>
<property name="jdbcUrl" value="${jdbc.url}"/>
<property name="user" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
<!-- c3p0连接池的私有属性 -->
<property name="maxPoolSize" value="30"/>
<property name="minPoolSize" value="10"/>
<!-- 关闭连接后不自动commit -->
<property name="autoCommitOnClose" value="false"/>
<!-- 获取连接超时时间 -->
<property name="checkoutTimeout" value="10000"/>
<!-- 当获取连接失败重试次数 -->
<property name="acquireRetryAttempts" value="2"/>
</bean>
<!-- sqlSessionFactory-->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="configLocation" value="classpath:mybatis-config.xml"/>
</bean>
<!-- 配置 dao 接口扫描包-->
<bean id="mapperScannerConfigurer" class="org.mybatis.spring.mapper.MapperScannerConfigurer" >
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
<property name="basePackage" value="com.xg.mapper"/>
</bean>
</beans>
1.3.2、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>
<settings>
<setting name="logImpl" value="COMMONS_LOGGING"/>
</settings>
<typeAliases>
<package name="com.xg.pojo"/>
</typeAliases>
<mappers>
<package name="com.xg.mapper"/>
</mappers>
</configuration>
1.4、Service层
1.4.1、spring-service.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">
<!-- 扫描service包下 注解-->
<context:component-scan base-package="com.xg.service"/>
<context:annotation-config/>
<!-- 配置 事务-->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<!-- 注入 数据源-->
<property name="dataSource" ref="dataSource"/>
</bean>
<!-- 将 我们们的所有 业务类注册到spring
可以通过配置或者, <bean id="" class="">
注解实现 @Service
-->
</beans>
1.5、Web 层
1.5.1、添加Web框架
1.5.2、web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<!-- 视图解析器-->
<servlet>
<servlet-name>app</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<!-- 一定要注意 绑定的文件 applicationContext.xml-->
<param-value>classpath:applicationContext.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>app</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<!--字符编码过滤器 -->
<filter>
<filter-name>encoding</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>encoding</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<session-config>
<!-- session 过期时间-->
<session-timeout>15</session-timeout>
</session-config>
</web-app>
1.5.3、spring-mvc.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!-- 开启注解支持， 静态资源过滤 -->
<context:component-scan base-package="com.xg.controller"/>
<mvc:default-servlet-handler/>
<mvc:annotation-driven>
<!--JSON 乱码问题-->
<mvc:message-converters register-defaults="true">
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<constructor-arg value="UTF-8"/>
</bean>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="objectMapper">
<bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
<property name="failOnEmptyBeans" value="false"/>
</bean>
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
<!-- 视图解析器-->
<bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/"/>
<property name="suffix" value=".jsp"/>
</bean>
</beans>
1.6、最后配置
1.6.1、配置 Tomcat
1.6.2、添加 lib
1.6.3、books.jsp
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
<style>
.table {
line-height: 1.6;
font: 14px Helvetica Neue, Helvetica, PingFang SC, Tahoma, Arial, sans-serif;
-webkit-tap-highlight-color: rgba(0, 0, 0, 0);
border-collapse: collapse;
border-spacing: 0;
margin: 10px 0;
30%;
background-color: #fff;
color: #666;
}
.table th{
text-align: left;
}
</style>
</head>
<body>
<table class="table">
<thead>
<tr>
<th style=" 100px">书籍编号</th>
<th style=" 180px">书籍名称</th>
<th style=" 120px">书籍数量</th>
<th style=" 250px">书籍详情</th>
</tr>
</thead>
<tbody>
<c:forEach var="book" items="${booksList}">
<tr>
<td>${book.bookID}</td>
<td>${book.bookName}</td>
<td>${book.bookCounts}</td>
<td>${book.detail}</td>
</tr>
</c:forEach>
</tbody>
</table>
</body>
</html>
1.6.4、测试 Controller
BooksController
package com.xg.controller;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.xg.service.books.BooksServiceImpl;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.HashMap;
@RestController
public class BooksController {
private final ObjectMapper objectMapper = new ObjectMapper();
private final BooksServiceImpl booksService;
public BooksController(BooksServiceImpl booksService) {
this.booksService = booksService;
}
@RequestMapping(value = "getBooksListJSON", produces = "application/json")
public String getBooksListJSON() throws JsonProcessingException {
return objectMapper.writeValueAsString(booksService.queryBooks());
}
@RequestMapping(value = "getBooksListJSON02", produces = "application/json")
public String getBooksListJSON02() throws JsonProcessingException {
HashMap<String, Object> map = new HashMap<>();
map.put("booksList", booksService.queryBooks());
map.put("username", "遇见星光");
map.put("count", 10);
map.put("page", 1);
return objectMapper.writeValueAsString(map);
}
}
> BooksController02
```java
package com.xg.controller;
import com.xg.pojo.Books;
import com.xg.service.books.BooksServiceImpl;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import java.util.List;
@Controller
public class BooksController02 {
private final BooksServiceImpl booksService;
public BooksController02(BooksServiceImpl booksService) {
this.booksService = booksService;
}
@RequestMapping("/allBooks")
public String queryBooksList(Model model) {
List<Books> booksList = booksService.queryBooks();
model.addAttribute("booksList", booksList);
return "books";
}
}
1.6.3.1、结果
1.7、排错思路
1.7.1、问题 ：bean不存在
步骤：
-
查看这个bean注入是否成功
-
Junit单元测试，看我们的代码是否可以查询出结果
-
问题，一定出在底层，是spring出了问题
-
springMVC，整合的时候没有调用到我们的service层的bean
-
applioncationContext.xml 没有注入bean
-
web.xml 中，我们也绑过配置文件！ ，发现问题我们配置的是 spring-MVC.xml
这里面确实没有 service bean ，所以空指针异常
-