框架整合——SSM（SpringMVC+Spring+MyBatis）CRUD（增删改查）Demo

一、SSM框架中各层级间的作用及关系

表现层（springMVC）：Controller层（Handler层）
负责具体的业务模块流程的控制
Controller层通过要调用Service层的接口来控制业务流程，控制的
配置也在Spring配置文件里面。

业务层（Spring）：Service层
Service层：负责业务模块的逻辑应用设计。
首先设计其接口，然后再实现他的实现类。
通过对Spring配置文件中配置其实现的关联，完成此步工作，我们
就可以通过调用Service的接口来进行业务处理。
最后通过调用DAO层已定义的接口，去实现Service具体的 实现类。

持久层（Mybatis）：Dao层（Mapper层）
Dao层：负责与数据库进行交互设计，用来处理数据的持久化工作。
DAO层的设计首先是设计DAO的接口，
然后在Spring的配置文件中定义此接口的实现类，就可在其他模块中
调用此接口来进行数据业务的处理，而不用关心接口的具体实现类是
哪个类，这里用到的就是反射机制， DAO层的数据源配置，以及有
关数据库连接的参数都在Spring的配置文件中进行配置。

视图层：View层
负责前台jsp页面的展示。
此层需要与Controller层结合起来开发。

各层间的联系：
本来Controller层与View层是可以放在.jsp文件里一起开发的，但是为了降低代码的复杂度，提高其可维护性，将其分为了这两层，这也体现了MVC框架的特性，即结构清晰，耦合度低。

Service层是建立在DAO层之上的，建立了DAO层后才可以建立Service层，而Service层又是在Controller层之下的，因而Service层应该既调用DAO层的接口，又要提供接口给Controller层的类来进行调用，它刚好处于一个中间层的位置。每个模型都有一个Service接口，每个接口分别封装各自的业务处理方法。

二、三层架构运行流程

三、SSM整合-CRUD（增删改查） Demo

1、功能点

• 分页
• 数据校验（jquery前端校验+JSR303后端校验）（最好加上数据库约束）
• ajax
• Rest风格的URL；使用HTTP协议请求方式的动词，来表示对资源的操作（GET（查询），POST（新增），PUT（修改），DELETE（删除））

2、技术点

• 基础框架-SSM（SpringMVC+Spring+MyBatis）
• 数据库-MySQL
• 前端框架-bootstrap快速搭建简洁美观的界面
• 项目的依赖管理-Maven
• 分页-pagehelper
• 逆向工程-MyBatis Generator

3、基础环境搭建

3.1、创建一个maven webapp工程

3.2、引入项目依赖的jar包

• spirng
• springmvc
• mybatis
• 数据库连接池，驱动
• 其他（jstl，servlet-api，junit）

pom.xml

<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>4.0.0modelVersion>

    <groupId>com.saogroupId>
    <artifactId>MySSMDemoartifactId>
    <version>1.0-SNAPSHOTversion>

    <dependencies>
        
        <dependency>
            <groupId>junitgroupId>
            <artifactId>junitartifactId>
            <version>4.12version>
        dependency>
        
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-webmvcartifactId>
            <version>4.3.7.RELEASEversion>
        dependency>
        
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-jdbcartifactId>
            <version>4.3.7.RELEASEversion>
        dependency>
        
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-testartifactId>
            <version>4.3.7.RELEASEversion>
        dependency>
        
        <dependency>
            <groupId>org.springframeworkgroupId>
            <artifactId>spring-aspectsartifactId>
            <version>4.3.7.RELEASEversion>
        dependency>
        
        <dependency>
            <groupId>org.mybatisgroupId>
            <artifactId>mybatisartifactId>
            <version>3.4.2version>
        dependency>
        
        <dependency>
            <groupId>org.mybatisgroupId>
            <artifactId>mybatis-springartifactId>
            <version>1.3.1version>
        dependency>
        
        <dependency>
            <groupId>c3p0groupId>
            <artifactId>c3p0artifactId>
            <version>0.9.1version>
        dependency>
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <version>5.1.41version>
        dependency>
        
        <dependency>
            <groupId>jstlgroupId>
            <artifactId>jstlartifactId>
            <version>1.2version>
        dependency>
        <dependency>
            <groupId>javax.servletgroupId>
            <artifactId>javax.servlet-apiartifactId>
            <version>3.0.1version>
            <scope>providedscope>
        dependency>
        <dependency>
            <groupId>javax.servletgroupId>
            <artifactId>jsp-apiartifactId>
            <version>2.0version>
            <scope>providedscope>
        dependency>
        
        <dependency>
            <groupId>com.github.pagehelpergroupId>
            <artifactId>pagehelperartifactId>
            <version>5.0.0version>
        dependency>
        
        <dependency>
            <groupId>com.fasterxml.jackson.coregroupId>
            <artifactId>jackson-databindartifactId>
            <version>2.8.8version>
        dependency>
    dependencies>

project>

3.3、引入bootstrap前端框架

bootstrap官网下载

将下载的包解压放入项目，以及添加jquery-3.3.1.min.js

4、编写SSM整合的关键配置文件

4.1、目录结构

4.2、web.xml

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://java.sun.com/xml/ns/javaee"
         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">

    
    
    <context-param>
        <param-name>contextConfigLocationparam-name>
        <param-value>classpath:applicationContext.xmlparam-value>
    context-param>

    
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListenerlistener-class>
    listener>

    
    
    <servlet>
        <servlet-name>dispatcherServletservlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
        <load-on-startup>1load-on-startup>
    servlet>

    
    <servlet-mapping>
        <servlet-name>dispatcherServletservlet-name>
        <url-pattern>/url-pattern>
    servlet-mapping>

    
    <filter>
        <filter-name>CharacterEncodingFilterfilter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilterfilter-class>
        <init-param>
            <param-name>encodingparam-name>
            <param-value>utf-8param-value>
        init-param>
        <init-param>
            <param-name>forceRequestEncodingparam-name>
            <param-value>trueparam-value>
        init-param>
        <init-param>
            <param-name>forceResponseEncodingparam-name>
            <param-value>trueparam-value>
        init-param>
    filter>
    <filter-mapping>
        <filter-name>CharacterEncodingFilterfilter-name>
        <url-pattern>/*url-pattern>
    filter-mapping>

    
    <filter>
        <filter-name>HiddenHttpMethodFilterfilter-name>
        <filter-class>org.springframework.web.filter.HiddenHttpMethodFilterfilter-class>
    filter>
    <filter-mapping>
        <filter-name>HiddenHttpMethodFilterfilter-name>
        <url-pattern>/*url-pattern>
    filter-mapping>
    <filter>
        <filter-name>HttpPutFormContentFilterfilter-name>
        <filter-class>org.springframework.web.filter.HttpPutFormContentFilterfilter-class>
    filter>
    <filter-mapping>
        <filter-name>HttpPutFormContentFilterfilter-name>
        <url-pattern>/*url-pattern>
    filter-mapping>


web-app>

4.3、dispatcherServlet-servlet.xml

<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/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">

    
    <context:component-scan base-package="com.sao" use-default-filters="false">
        
        <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
    context:component-scan>

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

    
    
    <mvc:default-servlet-handler/>
    
    <mvc:annotation-driven/>

beans>

4.4、applicationContext.xml

<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:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">

    <context:component-scan base-package="com.sao">
        <context:exclude-filter type="annotation"
                                expression="org.springframework.stereotype.Controller" />
    context:component-scan>

    
    
    <context:property-placeholder location="classpath:jdbc.properties" />
    <bean id="pooledDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="jdbcUrl" value="${jdbc.url}">property>
        <property name="driverClass" value="${jdbc.driverClass}">property>
        <property name="user" value="${jdbc.username}">property>
        <property name="password" value="${jdbc.password}">property>
    bean>

    
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        
        <property name="configLocation" value="classpath:mybatis-config.xml">property>
        <property name="dataSource" ref="pooledDataSource">property>
        
        <property name="mapperLocations" value="classpath:mapper/*.xml">property>
    bean>

    
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        
        <property name="basePackage" value="com.sao.dao">property>
    bean>

    
    <bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
        <constructor-arg name="sqlSessionFactory" ref="sqlSessionFactory">constructor-arg>
        <constructor-arg name="executorType" value="BATCH">constructor-arg>
    bean>
    

    
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        
        <property name="dataSource" ref="pooledDataSource">property>
    bean>
    
    <aop:config>
        
        <aop:pointcut expression="execution(* com.sao.service..*(..))" id="txPoint"/>
        
        <aop:advisor advice-ref="txAdvice" pointcut-ref="txPoint"/>
    aop:config>

    
    <tx:advice id="txAdvice" transaction-manager="transactionManager">
        <tx:attributes>
            
            <tx:method name="*"/>
            
            <tx:method name="get*" read-only="true"/>
        tx:attributes>
    tx:advice>

    

beans>

4.5、jdbc.properties

jdbc.url=jdbc:mysql://localhost:3306/ssm?useSSL=true&characterEncoding=UTF-8
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.username=root
jdbc.password=123456

4.6、mybatis-config.xml

<configuration>
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    settings>

    <typeAliases>
        <package name="com.sao.entity"/>
    typeAliases>

    <plugins>
        <plugin interceptor="com.github.pagehelper.PageInterceptor">
            
            <property name="reasonable" value="true"/>
        plugin>
    plugins>

configuration>

5、使用Mybatis-generator插件快速生成代码

Mysql数据库表

t_dept

t_emp

5.1、在pom.xml添加如下代码：

<build>
        <plugins>
            <plugin>
                
                <groupId>org.mybatis.generatorgroupId>
                <artifactId>mybatis-generator-maven-pluginartifactId>
                <version>1.3.2version>
                <configuration>
                    
                    <configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xmlconfigurationFile>
                    <verbose>trueverbose>
                    <overwrite>trueoverwrite>
                configuration>
            plugin>
        plugins>
    build>

5.2、在resources下的generator创建generatorConfig.xml

<generatorConfiguration>
    
    <classPathEntry    location="mysql-connector-java-5.1.46-bin.jar"/>
    <context id="testTables" targetRuntime="MyBatis3">
        <commentGenerator>
            
            <property name="suppressAllComments" value="true" />
        commentGenerator>
        
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://localhost:3306/ssm"
                        userId="root"
                        password="123456">
        jdbcConnection>
        
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false" />
        javaTypeResolver>

        
        <javaModelGenerator targetPackage="com.sao.entity"
                            targetProject="src/main/java">
            
            <property name="enableSubPackages" value="false" />
            
            <property name="trimStrings" value="true" />
        javaModelGenerator>
        
        <sqlMapGenerator targetPackage="mapper"
                         targetProject="src/main/resources">
            
            <property name="enableSubPackages" value="false" />
        sqlMapGenerator>
        
        <javaClientGenerator type="XMLMAPPER"
                             targetPackage="com.sao.dao"
                             targetProject="src/main/java">
            
            <property name="enableSubPackages" value="false" />
        javaClientGenerator>
        
        <table tableName="t_emp" domainObjectName="Employee">table>
        <table tableName="t_dept" domainObjectName="Department">table>
    context>
generatorConfiguration>

注意：将mysql-connector-java-5.1.46-bin.jar包放入项目

5.3、在plugins中找到mybatis-generator plugin，运行

附上工程目录结构及自动生成的文件

6、根据需求修改mapper文件

6.1、在EmployeeMapper.java添加：

/*自己定义查询，带上部门信息*/
List selectByExampleWithDept(EmployeeExample example);
/*自己定义查询，带上部门信息*/
Employee selectByPrimaryKeyWithDept(Integer id);

6.2、在Employee.java添加：

//希望查询员工信息的同时也可以查询部门信息
    private Department department;

    public Department getDepartment() {
        return department;
    }

    public void setDepartment(Department department) {
        this.department = department;
    }

6.3、在EmployeeMapper.xml中添加：

 
  <resultMap id="WithDeptResultMap" type="com.sao.entity.Employee">
    <id column="id" property="id" jdbcType="INTEGER" />
    <result column="name" property="name" jdbcType="VARCHAR" />
    <result column="gender" property="gender" jdbcType="CHAR" />
    <result column="email" property="email" jdbcType="VARCHAR" />
    <result column="d_id" property="dId" jdbcType="INTEGER" />
    <association property="department" javaType="com.sao.entity.Department">
      <id column="did" property="id" jdbcType="INTEGER" />
      <result column="dname" property="name" jdbcType="VARCHAR" />
    association>
  resultMap>


  <sql id="WithDept_Column_List">
    e.id, e.name, e.gender, e.email, e.d_id, d.id did, d.name dname
  sql>

 
  <select id="selectByExampleWithDept" resultMap="WithDeptResultMap">
    select
    <if test="distinct" >
      distinct
    if>
    <include refid="WithDept_Column_List" />
    from t_emp e
    left join t_dept d on e.d_id= d.id
    <if test="_parameter != null" >
      <include refid="Example_Where_Clause" />
    if>
    <if test="orderByClause != null" >
      order by ${orderByClause}
    if>
  select>
  <select id="selectByPrimaryKeyWithDept" resultMap="WithDeptResultMap">
    select
    <include refid="WithDept_Column_List" />
    from t_emp e
    left join t_dept d on e.d_id= d.id
    where e.id = #{id,jdbcType=INTEGER}
  select>

6、Jsp
index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<jsp:forward page="/emps">jsp:forward>

views下的list.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
         pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>员工列表title>
    <%
        pageContext.setAttribute("APP_PATH", request.getContextPath());
    %>
    
    <script type="text/javascript"
            src="${APP_PATH }/static/js/jquery-3.3.1.min.js">script>
    <link
            href="${APP_PATH }/static/bootstrap-3.3.7-dist/css/bootstrap.min.css"
            rel="stylesheet">
    <script
            src="${APP_PATH }/static/bootstrap-3.3.7-dist/js/bootstrap.min.js">script>
head>
<body>

<div class="container">
    
    <div class="row">
        <div class="col-md-12">
            <h1>SSM-CRUDh1>
        div>
    div>
    
    <div class="row">
        <div class="col-md-4 col-md-offset-8">
            <button class="btn btn-primary">新增button>
            <button class="btn btn-danger">删除button>
        div>
    div>
    
    <div class="row">
        <div class="col-md-12">
            <table class="table table-hover">
                <tr>
                    <th>#th>
                    <th>empNameth>
                    <th>genderth>
                    <th>emailth>
                    <th>deptNameth>
                    <th>操作th>
                tr>
                <c:forEach items="${pageInfo.list }" var="emp">
                    <tr>
                        <th>${emp.id }th>
                        <th>${emp.name }th>
                        <th>${emp.gender=="M"?"男":"女" }th>
                        <th>${emp.email }th>
                        <th>${emp.department.name }th>
                        <th>
                            <button class="btn btn-primary btn-sm">
                                <span class="glyphicon glyphicon-pencil" aria-hidden="true">span>
                                编辑
                            button>
                            <button class="btn btn-danger btn-sm">
                                <span class="glyphicon glyphicon-trash" aria-hidden="true">span>
                                删除
                            button>
                        th>
                    tr>
                c:forEach>
            table>
        div>
    div>

    
    <div class="row">
        
        <div class="col-md-6">当前 ${pageInfo.pageNum }页,总${pageInfo.pages }
            页,总 ${pageInfo.total } 条记录div>
        
        <div class="col-md-6">
            <nav aria-label="Page navigation">
                <ul class="pagination">
                    <li><a href="${APP_PATH }/emps?pn=1">首页a>li>
                    <c:if test="${pageInfo.hasPreviousPage }">
                        <li><a href="${APP_PATH }/emps?pn=${pageInfo.pageNum-1}"
                               aria-label="Previous"> <span aria-hidden="true">«span>
                        a>li>
                    c:if>


                    <c:forEach items="${pageInfo.navigatepageNums }" var="page_Num">
                        <c:if test="${page_Num == pageInfo.pageNum }">
                            <li class="active"><a href="#">${page_Num }a>li>
                        c:if>
                        <c:if test="${page_Num != pageInfo.pageNum }">
                            <li><a href="${APP_PATH }/emps?pn=${page_Num }">${page_Num }a>li>
                        c:if>

                    c:forEach>
                    <c:if test="${pageInfo.hasNextPage }">
                        <li><a href="${APP_PATH }/emps?pn=${pageInfo.pageNum+1 }"
                               aria-label="Next"> <span aria-hidden="true">»span>
                        a>li>
                    c:if>
                    <li><a href="${APP_PATH }/emps?pn=${pageInfo.pages}">末页a>li>
                ul>
            nav>
        div>
    div>

div>
body>
html>

8、Service

EmployeeService .java

public interface EmployeeService {
    public List getAll();
}

EmployeeServiceImpl.java

package com.sao.service.impl;

import com.sao.dao.EmployeeMapper;
import com.sao.entity.Employee;
import com.sao.service.EmployeeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class EmployeeServiceImpl implements EmployeeService {
    @Autowired
    EmployeeMapper employeeMapper;

    /**
     * 查询所有员工
     * @return
     */
    public List getAll() {
        return employeeMapper.selectByExampleWithDept(null);
    }
}

9、Controller

EmployeeController .java

package com.sao.controller;

import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import com.sao.entity.Employee;
import com.sao.service.EmployeeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;

import java.util.List;

/**
 * 处理员工CRUD请求
 */
@Controller
public class EmployeeController {
    @Autowired
    EmployeeService employeeService;

    /**
     * 查询员工数据（分页查询）
     * @return
     */
    @RequestMapping("/emps")
    public String getEmps(@RequestParam(value = "pn", defaultValue = "1")Integer pn, Model model){
        // 引入PageHelper分页插件（导包，配置文件配置）
        // 在查询之前只需要调用，传入页码，以及每页的大小
        PageHelper.startPage(pn, 5);
        // startPage后面紧跟的这个查询就是一个分页查询
        List emps = employeeService.getAll();
        // 使用pageInfo包装查询后的结果，只需要将pageInfo交给页面就行了。
        // 封装了详细的分页信息,包括有我们查询出来的数据，传入连续显示的页数
        PageInfo page = new PageInfo(emps, 5);
        model.addAttribute("pageInfo", page);
        return "list";
    }
}

10、访问jsp

访问http://localhost:8080/index.jsp将跳转到views下的list.jsp显示列表信息

四、最后

目前已经实现对信息的分页查询，由于篇幅过长，后续CRUD代码就不再博文中写出；

另外：现在的写法（转发页面）只适用于浏览器与后台交互的模型，如果在安卓，ios端则解析的话比较费劲，所以推荐使用ajax+json的形式向前台传递数据；

JSON(JavaScript Object Notation, JS 对象标记) 是一种轻量级的数据交换格式。可以方便的实现数据的跨平台交换。

分页查询-ajax：
1、index.jsp页面直接发送ajax请求进行员工分页数据的查询
2、服务器将查出的数据，以json字符串的形式返回给浏览器
3、浏览器收到js字符串，可以使用js对json进行解析，使用js通过dom增删改改变页面
4、返回json。实现客户端的无关系

EmployeeController .java

@RequestMapping("/emps")
    @ResponseBody
    public PageInfo getEmpsWithJson(@RequestParam(value = "pn",defaultValue = "1")Integer pn){
        // 引入PageHelper分页插件
        // 在查询之前只需要调用，传入页码，以及每页的大小
        PageHelper.startPage(pn,5);
        // startPage后面紧跟的这个查询就是一个分页查询
        List employees=employeeService.getAll();
        // 使用pageInfo包装查询后的结果，只需要将pageInfo交给页面就行了。
        // 封装了详细的分页信息,包括有我们查询出来的数据，传入连续显示的页数
        PageInfo pageInfo=new PageInfo(employees,5);
        return pageInfo;
    }

使用@ResponseBody返回json形式的数据
注意：使用@ResponseBody需要导jar包