SSM（springmvc + spring + MyBatis）整合开发

1、SSM编程的基本介绍

SSM 编程，即 springmvc + spring + MyBatis 整合，是当前最为流行的 javaEE 开发技术架构。

• springmvc：视图层、界面层，负责接收请求，返回处理结果
• spring：业务层，管理 service、dao、工具类对象
• MyBatis：持久层，负责操作数据库

2、SSM整合示例

首先，先在 idea 中通过 maven 创建一个 web 项目，手动添加 src/main/java 和 src/main/resources 目录。初始目录结构如下：

2.1、建表语句

下面会用到student表，建表语句如下：

DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(80) DEFAULT NULL,
  `age` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

2.2、pom.xml 文件配置

在 pom.xml 配置文件中添加依赖，并且配置一些 build 选项：

<?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/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.example</groupId>
  <artifactId>mybatis_spring</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>mybatis_spring Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>

    <!--servlet-->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <scope>provided</scope>
    </dependency>

    <!--jsp-->
    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>javax.servlet.jsp-api</artifactId>
      <version>2.3.1</version>
      <scope>provided</scope>
    </dependency>

    <!--springmvc-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.2.5.RELEASE</version>
    </dependency>

    <!--事务相关-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
      <version>5.2.5.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>5.2.5.RELEASE</version>
    </dependency>

    <!--jackson-->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>2.9.0</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.9.0</version>
    </dependency>

    <!--mybatis-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.6</version>
    </dependency>
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.3.1</version>
    </dependency>

    <!-- mysql -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.9</version>
    </dependency>

    <!-- druid -->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.1.12</version>
    </dependency>

  </dependencies>

  <build>
    <!--将src下以及resources目录下的properties、xml文件编译后写出到target目录-->
    <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>
</project>

2.3、web.xml 文件配置

在 web.xml 文件中配置 springmvc 和 spring：

<?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">

  <!-- SpringMVC的前端控制器 -->
  <servlet>
    <servlet-name>springmvcTest</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

    <!-- 自定义springmvc的配置文件的位置-->
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:conf/dispatcherServlet.xml</param-value>  <!--指定配置文件的位置-->
    </init-param>

    <!-- 指定该servlet对象在tomcat启动时即创建-->
    <load-on-startup>1</load-on-startup>
  </servlet>

  <servlet-mapping>
    <servlet-name>springmvcTest</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>

  <!--注册spring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>

  <!--注册字符集过滤器 强制utf-8编码-->
  <filter>
    <filter-name>characterEncodingFilter</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>
    <init-param>
      <param-name>forceRequestEncoding</param-name>
      <param-value>true</param-value>
    </init-param>
    <init-param>
      <param-name>forceResponseEncoding</param-name>
      <param-value>true</param-value>
    </init-param>
  </filter>
  <filter-mapping>
    <filter-name>characterEncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>

2.4、新建包、目录、配置文件

在 src/main/resouces 目录下新建文件夹 conf，用来存放一系列的配置文件。如在上面 web.xml 配置中所指定的 springmvc 的配置文件 dispatcherServlet.xml、spring 的配置文件 applicationContext.xml、jdbc.properties 和 mybatis.xml 。

在 src/main/java 目录下新建包如 mypackage，在该包新建一系列包，如 service、dao、domain、controller。

最后目录结构如下：

2.5、spring 的配置文件 applicationContext.xml

主要是配置service和dao

<?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的配置文件：声明service、dao、工具类等对象-->


    <!--获取数据库连接信息-->
    <context:property-placeholder location="classpath:conf/jdbc.properties" />
    <!--使用druid数据源-->
    <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>

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

    <!--声明 service的注解@Service所在包的位置-->
    <context:component-scan base-package="mypackage.service" />

    <!--事务配置（注解或aspectj）-->
</beans>

2.6、springmvc 的配置文件 dispatcherServlet.xml

配置spirngMVC，主要是组件controller、视图view的配置

<?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">

<!--    springmvc的配置文件，声明controller和其它web相关的对象-->

    <!--组件扫描器-->
    <context:component-scan base-package="mypackage.domain,mypackage.dao,mypackage.service,mypackage.controller" />
    <!--视图解析器-->
    <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-->
    <mvc:annotation-driven />
</beans>

 2.7、数据库配置文件 jdbc.properties

数据库配置文件配置数据库连接的基本信息，示例：

jdbc.url=jdbc:mysql://localhost:3306/userDB
jdbc.username=root
jdbc.password=123456

上面的 userDB 为数据库名称。 

2.8、mybatis 的配置文件mybatis.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>
    <!--开启mybatis日志-->
    <settings>
        <setting name="logImpl" value="STDOUT_LOGGING"/>
    </settings>

    <!--配置别名-->
    <typeAliases>
        <!-- 实体类所在的包名-->
        <package name="mypackage.domain"/>
    </typeAliases>

    <!--sql mapper文件的位置-->
    <mappers>
        <package name="mypackage.dao"/>
    </mappers>

</configuration>

2.9、编写java代码

最终的 java 代码目录结构如下：

2.9.1、先建立实体类（domain）

Student 类：

package mypackage.domain;

public class Student {
    private Integer id;
    private String name;
    private Integer age;

    public Integer getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public Integer getAge() {
        return age;
    }

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

2.9.2、controller 层

StudentController 类：

package mypackage.controller;

import mypackage.domain.Student;
import mypackage.service.StudentService;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.servlet.ModelAndView;

import javax.annotation.Resource;
import java.util.List;

@Controller
@RequestMapping("/student")
public class StudentController {
    @Resource
    private StudentService service;

    //添加学生
    @RequestMapping("/addStudent.do")
    public ModelAndView addStudent(Student student){
        ModelAndView mv =new ModelAndView();
        String tips = "注册失败";
        //调用service处理
        int nums = service.addStudent(student);
        if(nums > 0){
            tips = "学生【"+student.getName()+"】注册成功";
        }
        //添加数据
        mv.addObject("tips", tips);
        //指定结果页面(逻辑名称)
        mv.setViewName("result");
        return mv;
    }

    //查询 返回json
    @RequestMapping("/queryStudent.do")
    @ResponseBody
    public List<Student> queryStudent(Student student){
        //省略参数检查以及数据处理
        List<Student> students = service.findStudents();
        return students;
    }
}

2.9.3、service 层

StudentService 接口：

package mypackage.service;

import mypackage.domain.Student;

import java.util.List;

public interface StudentService {
    int addStudent(Student student);
    List<Student> findStudents();
}

实现类 StudentServiceImpl ：

package mypackage.service.impl;

import mypackage.dao.StudentDao;
import mypackage.domain.Student;
import mypackage.service.StudentService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.List;

@Service
public class StudentServiceImpl implements StudentService {
    @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();
    }
}

2.9.4、dao 层

StudentDao 接口：

package mypackage.dao;


import mypackage.domain.Student;

import java.util.List;

public interface StudentDao {
    int insertStudent(Student student);
    List<Student> selectStudents();
}

mybatis 对应的SQL 文件，文件名跟上面的 dao 类一样，即名为：StudentDao.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="mypackage.dao.StudentDao">
    <select id="selectStudents" resultType="Student">
        select id,name,age from student order by id desc
    </select>

    <insert id="insertStudent">
        insert into student(name,age) values(#{name},#{age})
    </insert>
</mapper>

 2.10、编写 jsp 验证

jsp 文件最终目录结构如下：

index.jsp ：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%
    String basePath = request.getScheme()+"://" +
            request.getServerName() + ":" + request.getServerPort() +
            request.getContextPath() + "/";
%>
<html>
<head>
    <title>Title</title>
    <base href="<%=basePath%>">

</head>
<body>
<table align="center">
    <tr>
        <td><a href="addStudent.jsp">注册学生</a></td>
    </tr>
    <tr>
        <td><a href="listStudent.jsp">浏览学生</a></td>
    </tr>
</table>
</body>
</html>

listStudent.jsp ：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%
    String basePath = request.getScheme()+"://" +
            request.getServerName() + ":" + request.getServerPort() +
            request.getContextPath() + "/";
%>
<html>
<head>
    <title>查询学生 使用ajax</title>
    <base href="<%=basePath%>">
    <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
    <script type="text/javascript">
        $(function(){
            $.ajax({
                url:"student/queryStudent.do",
                dataType:"json",
                success:function(data){
                    $.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>
<table align="center">
    <thead>
    <tr>
        <td>学号</td>
        <td>姓名</td>
        <td>年龄</td>
    </tr>
    </thead>
    <tbody id="info">

    </tbody>

</table>
</body>
</html>

addStudent.jsp ：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%
    String basePath = request.getScheme()+"://" +
            request.getServerName() + ":" + request.getServerPort() +
            request.getContextPath() + "/";
%>
<html>
<head>
    <title>Title</title>
    <base href="<%=basePath%>">
</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;&nbsp;</td>
                    <td><input type="submit" value="提交"></td>
                </tr>
            </table>
        </form>
    </div>
</body>
</html>

jsp/result.jsp ：

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    结果：${tips}
</body>
</html>