Chapter3 SSM整合开发

3.1 SSM简介

3.1.1 SSM编程

  1. SSM即 SpringMVC + Spring + MyBatis
    • SpringMVC:视图层，界面层，负责接收请求，显示处理结果的。
    • Spring：业务层，管理service，dao，工具类对象的。
    • MyBatis：持久层， 访问数据库的
  2. SSM 整合的实现方式可分为两种：
    • 基于 XML 配置方式
    • 基于注解方式

3.1.2 三者关系

  1. SSM整合也叫做SSI (IBatis也就是mybatis的前身)， 整合中有两个容器。
    • SpringMVC容器， 管理Controller控制器对象
    • Spring容器，管理Service，Dao,工具类对象
  2. 配置文件
    • 把Controller还有web开发的相关对象交给springmvc容器， 这些web用的对象写在springmvc配置文件中
    • 把service，dao对象定义在spring的配置文件中，让spring管理这些对象。
  3. 关系
    • springmvc容器是spring容器的子容器， 类似java中的继承。 子可以访问父的内容
    • 在子容器中的Controller可以访问父容器中的Service对象， 就可以实现controller使用service对象

3.2 搭建 SSM 开发环境

3.2.1 新建项目

  1. 新建maven项目
  2. 加入依赖
    • springmvc，spring，mybatis三个框架的依赖
    • jackson依赖，
    • mysql驱动、druid连接池
    • jsp，servlet
  3. 插件
  4. pom.xml:
    <properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
<build>
<resources>
    <resource>
    <directory>src/main/java</directory><!--所在的目录-->
    <includes><!--包括目录下的.properties,.xml 文件都会扫描到-->
        <include>**/*.properties</include>
        <include>**/*.xml</include>
    </includes>
    <filtering>false</filtering>
    </resource>
</resources>
<plugins>
    <plugin>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.1</version>
    <configuration>
        <source>1.8</source>
        <target>1.8</target>
    </configuration>
    </plugin>
</plugins>
</build>

<dependencies>

<!-- https://mvnrepository.com/artifact/org.junit.jupiter/junit-jupiter-api -->
<dependency>
    <groupId>org.junit.jupiter</groupId>
    <artifactId>junit-jupiter-api</artifactId>
    <version>5.6.2</version>
    <scope>test</scope>
</dependency>

<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.2.9.RELEASE</version>
</dependency>

<!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>3.1.0</version>
    <scope>provided</scope>
</dependency>

<!-- https://mvnrepository.com/artifact/javax.servlet.jsp/javax.servlet.jsp-api -->
<dependency>
    <groupId>javax.servlet.jsp</groupId>
    <artifactId>javax.servlet.jsp-api</artifactId>
    <version>2.3.3</version>
    <scope>provided</scope>
</dependency>

<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.11.3</version>
</dependency>

<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.11.3</version>
</dependency>

<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>3.5.3</version>
</dependency>

<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis-spring -->
<dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis-spring</artifactId>
    <version>2.0.5</version>
</dependency>

<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.21</version>
</dependency>

<!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>druid</artifactId>
    <version>1.2.3</version>
</dependency>

</dependencies>

3.2.2 配置 web.xml

  1. 内容
    • 注册 ContextLoaderListener 监听器
    • 注册字符集过滤器
    • 配置中央调度器
  2. 示例
      <!--注册springmvc的核心对象DispatcherServlet(中央调度器)-->
  <servlet>
  <servlet-name>ssm</servlet-name>
  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  <!--自定义springmvc读取的配置文件的位置-->
  <init-param>
      <!--springmvc的配置文件的位置的属性-->
      <param-name>contextConfigLocation</param-name>
      <!--指定自定义文件的位置-->
      <param-value>classpath:conf/dispatcherServlet.xml</param-value>
  </init-param>
  <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
  <servlet-name>ssm</servlet-name>
  <url-pattern>*.do</url-pattern>
  </servlet-mapping>

  <!--注册spring的监听器-->
  <context-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:conf/applicationContext.xml</param-value>
  </context-param>
<listener>
  <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

  <!--  声明过滤器，解决乱码问题  -->
  <filter>
      <filter-name>characterEncodingFilter</filter-name>
      <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
  <!--  设置过滤器参数  -->
      <!-- 字符编码 -->
      <init-param>
          <param-name>encoding</param-name>
          <param-value>utf-8</param-value>
      </init-param>
      <!-- 强制请求对象（HttpServletRequest）使用Encoding编码值 -->
      <init-param>
          <param-name>forceRequestEncoding</param-name>
          <param-value>true</param-value>
      </init-param>
      <!-- 强制应答对象（HttpServletResponse）使用Encoding编码值 -->
      <init-param>
          <param-name>forceResponseEncoding</param-name>
          <param-value>true</param-value>
      </init-param>
  </filter>
  <filter-mapping>
      <filter-name>characterEncodingFilter</filter-name>
      <!-- 强制所有请求先通过过滤器 -->
      <url-pattern>/*</url-pattern>
  </filter-mapping>

3.2.3 spring、springmvc、mybatis配置文件

  1. spring配置文件applicationContext.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">

    <!-- spring配置文件：声明service、dao、工具类等对象 -->

    <!--声明数据源，连接数据库-->
    <context:property-placeholder location="classpath:conf/jdbc.properties"/>
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
    </bean>

    <!--SqlSessionFactoryBean创建SqlSessionFactory-->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="configLocation" value="classpath:conf/mybatis.xml"/>
    </bean>

    <!--声明mybatis的扫描器，创建dao对象-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
        <property name="basePackage" value="com.powernode.dao"/>
    </bean>

    <!--声明service的注解@Service所在的包名位置-->
    <context:component-scan base-package="com.powernode.service"/>

    <!--事务配置：注解或aspectj-->

</beans>

  2. 数据库配置信息jdbc.properties

    jdbc.url=jdbc:mysql://localhost:3306/ssm?serverTimezone=UTC&characterEncoding=utf8&useSSL=false&serverTimezone=UTC&allowPublicKeyRetrieval=true
jdbc.username=root
jdbc.password=123456

  3. springmvc配置文件 dispatcherServlet.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.alibaba.com/schema/stat"
    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.alibaba.com/schema/stat http://www.alibaba.com/schema/stat.xsd">

    <!-- springmvc配置文件，声明controller和其它web相关的对象 -->
    <context:component-scan base-package="com.powernode.controller"/>

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!-- 注解驱动 -->
    <!--注意这个有多个，不要选错了：http://www.springframework.org/schema/mvc-->
    <mvc:annotation-driven/>
</beans>

  4. mybatis配置文件 mybatis.xml

    <configuration>
    <!--settings: 控制mybatis全局行为-->
    <settings>
        <!--日志-->
        <setting name="logImpl" value="STDOUT_LOGGING"/>
    </settings>
    
    <!--设置别名-->   
    <typeAliases>
        <!--name: 实体类所在的包名-->
        <package name="com.powernode.domain"/>
    </typeAliases>

    <!--sql mapper（sql映射文件）位置-->
    <mappers>
        <!--name: 包名-->
        <package name="com.powernode.dao"/>

        <!--也可使用resource-->
<!--        <mapper resource="com/powernode/dao/StudentDao.xml"/>-->
    </mappers>

</configuration>

3.3 SSM整合注解开发示例

3.3.1 准备工作

  1. 搭建开发环境：见上一节

  2. 项目结构

    +--- pom.xml
+--- src
|   +--- main
|   |   +--- java
|   |   |   +--- com
|   |   |   |   +--- powernode
|   |   |   |   |   +--- controller
|   |   |   |   |   +--- dao
|   |   |   |   |   +--- domain
|   |   |   |   |   +--- service
|   |   +--- resources
|   |   |   +--- conf
|   |   |   |   +--- applicationContext.xml
|   |   |   |   +--- dispatcherServlet.xml
|   |   |   |   +--- jdbc.properties
|   |   |   |   +--- mybatis.xml
|   |   +--- webapp
|   |   |   +--- WEB-INF
|   |   |   |   +--- applicationContext.xml
|   |   |   |   +--- jsp
|   |   |   |   +--- log4j.xml
|   |   |   |   +--- view
|   |   |   |   +--- web.xml

  3. 新建数据库表student

    create database springmvc;
use springmvc;
create table student(
    id int not null auto_increment,
    name varchar(80),
    age int,
    primary key (id)
);

3.3.2 类与接口

  1. 实体类Student
    public class Student {
    private Integer id;
    private String name;
    private Integer age;

    public void setId(Integer id) {
        this.id = id;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Integer getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public Integer getAge() {
        return age;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}
  2. StudentDao接口及mapper文件StudentDao.xml
    public interface StudentDao {

    int insertStudent(Student student);
    List<Student> selectStudents();
}
    <mapper namespace="com.powernode.dao.StudentDao">
    <select id="selectStudents" resultType="com.powernode.domain.Student">
        select id, name, age from student order by id;
    </select>
    <insert id="insertStudent">
        insert into student(name,age) values (#{name},#{age})
    </insert>
</mapper>
  3. StudentService接口
    public interface StudentService {

    int addStudent(Student student);
    List<Student> findStudents();
}
  4. 处理器 StudentController类
    @Controller
@RequestMapping("/student")
public class StudentController {

    @Resource
    private StudentService service;

    // 注册学生
    @RequestMapping("/addStudent.do")
    public ModelAndView addStudent(Student student) {
        ModelAndView mv = new ModelAndView();
        String tips = "注册失败";
        // 调用service处理student
        int nums = service.addStudent(student);
        if (nums>0){
            // 注册成功
            tips = "学生：" + student.getName() + "注册成功";
        }
        mv.addObject("tips",tips);
        mv.setViewName("result");
        return mv;
    }
}
  5. service接口及实现类
    public interface StudentService {

    int addStudent(Student student);
    List<Student> findStudents();
}
    @Service
public class StudentServiceImpl implements StudentService {

    // 引用类型自动注入@Autowired，@Resource
    @Resource
    private StudentDao studentDao;

    @Override
    public int addStudent(Student student) {
        int nums = studentDao.insertStudent(student);
        return nums;
    }

    @Override
    public List<Student> findStudents() {
        return studentDao.selectStudents();
    }
}

3.3.3 页面文件

  1. index.jsp

    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>首页</title>
</head>
<body>
    <div align="center">
        <p>SSM整合的案例</p>
        <img src="img/horse.png" height="200"/>
        <table>
            <tr>
                <td><a href="addStudent.jsp">注册学生</a></td>
            </tr>
            <tr>
                <td>浏览学生</td>
            </tr>
        </table>
    </div>
</body>
</html>

  2. addStudent.jsp

    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>注册学生</title>
</head>
<body>
    <div align="center">
        <form action="student/addStudent.do" method="post">
            <table>
                <tr>
                    <td>姓名：</td>
                    <td><input type="text" name="name"></td>
                </tr>
                <tr>
                    <td>年龄：</td>
                    <td><input type="text" name="age"></td>
                </tr>
                <tr>
                    <td>&nbsp;&nbsp;&nbsp;</td>
                    <td><input type="submit" name="注册"></td>
                </tr>
            </table>
        </form>
    </div>
</body>
</html>

  3. result.jsp

    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>result</title>
</head>
<body>
result.jsp 结果页面：注册结果： ${tips}
</body>
</html>

3.3.4 补充说明

  1. 项目目前结构

    +--- pom.xml
+--- src
|   +--- main
|   |   +--- java
|   |   |   +--- com
|   |   |   |   +--- powernode
|   |   |   |   |   +--- controller
|   |   |   |   |   |   +--- StudentController.java
|   |   |   |   |   +--- dao
|   |   |   |   |   |   +--- StudentDao.java
|   |   |   |   |   |   +--- StudentDao.xml
|   |   |   |   |   +--- domain
|   |   |   |   |   |   +--- Student.java
|   |   |   |   |   +--- service
|   |   |   |   |   |   +--- impl
|   |   |   |   |   |   |   +--- StudentServiceImpl.java
|   |   |   |   |   |   +--- StudentService.java
|   |   +--- resources
|   |   |   +--- conf
|   |   |   |   +--- applicationContext.xml
|   |   |   |   +--- dispatcherServlet.xml
|   |   |   |   +--- jdbc.properties
|   |   |   |   +--- mybatis.xml
|   |   +--- webapp
|   |   |   +--- addStudent.jsp
|   |   |   +--- img
|   |   |   |   +--- horse.png
|   |   |   +--- index.jsp
|   |   |   +--- WEB-INF
|   |   |   |   +--- applicationContext.xml
|   |   |   |   +--- jsp
|   |   |   |   |   +--- result.jsp
|   |   |   |   +--- log4j.xml
|   |   |   |   +--- web.xml

  2. 报错

    • 错误
      Client does not support authentication protocol requested by server
    • 解决:在mysql控制台执行命令
      alter user 'root'@'localhost' identified with mysql_native_password by 'hjp356908';

3.3.5 添加其他功能

  1. 添加查询功能，通过ajax请求完成

  2. 页面

    • index.jsp

      <tr>
    <td><a href="listStudent.jsp">浏览学生</a></td>
</tr>

    • listStudent.jsp

      <head>
    <title>查找学生ajax</title>
    <script type="text/javascript" src="js/jquery-3.4.1.js"></script>
    <script type="text/javascript">
        $(function (){
            //当前页面dom对象加载后，执行loadStudentData（）
            loadStudentData();
            $("#btnLoader").click(function (){
                loadStudentData();
            })
        })
        function loadStudentData(){
            $.ajax({
                url:"student/queryStudent.do",
                type:"get",
                dataType:"json",
                success:function (data){
                    // alert("data="+data);
                    // 清除旧数据
                    $("#info").html("");
                    //显示数据
                    $.each(data,function(i,n){
                        $("#info").append("<tr>")
                            .append("<td>"+n.id+"<td>")
                            .append("<td>"+n.name+"<td>")
                            .append("<td>"+n.age+"<td>")
                            .append("<tr>")
                    })
                }
            })
        }
    </script>
</head>
<body>
    <div align="center">
        <table>
            <thead>
            <tr>
                <td>学号</td>
                <td>姓名</td>
                <td>年龄</td>
            </tr>
            </thead>
            <tbody id="info">

            </tbody>
        </table>
        <input type="button" id="btnLoader" value="查询数据">
    </div>
</body>

  3. Controller

    // 处理查询，相应ajax
@RequestMapping("/queryStudent.do")
@ResponseBody
public List<Student> queryStudent() {
    // 参数检查，简单处理数据
    System.out.println("调用查询");
    List<Student> students = service.findStudents();
    System.out.println(students);
    return students;
}