暑期实训第三天

最新推荐文章于 2021-07-30 21:13:01 发布

CrazyShanShan

最新推荐文章于 2021-07-30 21:13:01 发布

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分类专栏：暑期实训

本文链接：https://blog.youkuaiyun.com/qq_38687678/article/details/95629191

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本文介绍了SSM（Spring+SpringMVC+MyBatis）框架，它是数据源较简单的web项目常用框架。Spring核心是IoC，MyBatis封装了jdbc。还详细阐述了搭建SSM框架的一般步骤，包括开发环境搭建、项目创建、文件夹目录建立、Maven引入jar包、框架整合及前端实现等。

什么是ssm框架

SSM（Spring+SpringMVC+MyBatis）框架集由Spring、MyBatis两个开源框架整合而成（SpringMVC是Spring中的部分内容）。常作为数据源较简单的web项目的框架。
Spring:　Spring就像是整个项目中装配bean的大工厂，在配置文件中可以指定使用特定的参数去调用实体类的构造方法来实例化对象。也可以称之为项目中的粘合剂。
　　Spring的核心思想是IoC（控制反转），即不再需要程序员去显式地new一个对象，而是让Spring框架帮你来完成这一切。
mybatis
　　mybatis是对jdbc的封装，它让数据库底层操作变的透明。mybatis的操作都是围绕一个sqlSessionFactory实例展开的。mybatis通过配置文件关联到各实体类的Mapper文件，Mapper文件中配置了每个类对数据库所需进行的sql语句映射。在每次与数据库交互时，通过sqlSessionFactory拿到一个sqlSession，再执行sql命令。

搭建ssm框架的一般步骤

1.开发环境搭建

见前一个博客：暑期实训第一天—ssm环境的环境搭建
关于jcbd的内容：暑期实训第二天——jdbc的初识

2.创建项目

创建项目
nexet
org代表非盈利项目，zbz随意，我写的个人姓名
next
填好自己的maven位置，和生成的properties所在的位置，不然后续会报错。

2.建立文件夹目录

参考暑期实训第二天的博客，建立好文件夹目录

其中：
bean存放实体类其和数据库对应
dao持久层其中写数据库的增删改查接口
service业务层
controller控制层
jsp存放前端页面
mapper存放数据库的sql操作
applicationContext.xml与数据库的连接相关
db.properties存放你的数据库的信息
log4j为日志配置文件
spring-mvc.xml为springmvc配置文件

3.Maven引入需要的jar包

pom.xml 实现自动导包，注意建立项目的时候选好仓库

<?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>com.whut</groupId>
  <artifactId>ssm1</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>ssm1 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>
    <!-- spring版本号 -->
    <spring.version>5.0.2.RELEASE</spring.version>
    <!-- mybatis版本号 -->
    <mybatis.version>3.2.6</mybatis.version>
    <!-- log4j日志文件管理包版本 -->
    <slf4j.version>1.7.7</slf4j.version>
    <log4j.version>1.2.17</log4j.version>
    <c3p0.version>0.9.5.2</c3p0.version>
    <taglibs.version>1.1.2</taglibs.version>
  </properties>

  <dependencies>
  <!-- spring核心包 -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>${spring.version}</version>
  </dependency>

  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
    <version>${spring.version}</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-oxm</artifactId>
    <version>${spring.version}</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-tx</artifactId>
    <version>${spring.version}</version>
  </dependency>

  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-jdbc</artifactId>
    <version>${spring.version}</version>
  </dependency>

  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>${spring.version}</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aop</artifactId>
    <version>${spring.version}</version>
  </dependency>

  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context-support</artifactId>
    <version>${spring.version}</version>
  </dependency>

  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-test</artifactId>
    <version>${spring.version}</version>
  </dependency>
  <!-- mybatis核心包 -->
  <dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis</artifactId>
    <version>${mybatis.version}</version>
  </dependency>
  <!-- mybatis/spring包 -->
  <dependency>
    <groupId>org.mybatis</groupId>
    <artifactId>mybatis-spring</artifactId>
    <version>1.2.2</version>
  </dependency>
  <!-- 导入java ee jar 包 -->
  <dependency>
    <groupId>javax</groupId>
    <artifactId>javaee-api</artifactId>
    <version>7.0</version>
  </dependency>

  <!-- 导入Mysql数据库链接jar包 -->
  <dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.30</version>
  </dependency>
  <!-- 导入dbcp的jar包，用来在applicationContext.xml中配置数据库 -->
  <dependency>
    <groupId>commons-dbcp</groupId>
    <artifactId>commons-dbcp</artifactId>
    <version>1.2.2</version>
  </dependency>
  <!-- JSTL标签类 -->
  <dependency>
    <groupId>jstl</groupId>
    <artifactId>jstl</artifactId>
    <version>1.2</version>
  </dependency>
  <!-- 日志文件管理包 -->
  <!-- log start -->
  <dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>${log4j.version}</version>
  </dependency>


  <!-- 数据连接池 -->
  <dependency>
    <groupId>com.mchange</groupId>
    <artifactId>c3p0</artifactId>
    <version>${c3p0.version}</version>
  </dependency>

  <dependency>
    <groupId>taglibs</groupId>
    <artifactId>standard</artifactId>
    <version>${taglibs.version}</version>
  </dependency>

  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId>
    <version>${slf4j.version}</version>
  </dependency>
  <dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-log4j12</artifactId>
    <version>${slf4j.version}</version>
  </dependency>

  <!-- 导入servlet-api/jsp -->
  <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>2.3.1</version>
    <scope>provided</scope>
  </dependency>


  </dependencies>


  <build>
    <finalName>ssm1</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

4.Spring与MyBatis整合

其最终目录结构如下：

1.建立jdbc的属性文件

db.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/user
jdbc.username=zbz
jdbc.password=646509whutzbz

2.建立配置数据库的.xml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"
       xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
		http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
		http://www.springframework.org/schema/context
		http://www.springframework.org/schema/context/spring-context-4.3.xsd
		http://www.springframework.org/schema/aop
		http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
		http://www.springframework.org/schema/tx
		http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">
    <!-- 1.配置数据库相关参数properties的属性：${url} -->
    <context:property-placeholder location="classpath:db.properties"/>

    <!-- 2.配置数据源 -->
    <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}"/>
        <property name="maxPoolSize" value="30"/>
        <property name="minPoolSize" value="2"/>
    </bean>

    <!-- 3.配置SqlSessionFactory对象 -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!-- 注入数据库连接池 -->
        <property name="dataSource" ref="dataSource"/>
        <!-- 扫描bean包 使用别名 -->
        <property name="typeAliasesPackage" value="com.whut.bean"></property>

        <!--配置加载映射文件 UserMapper.xml-->
        <property name="mapperLocations" value="classpath:mapper/*.xml"/>

    </bean>

    <!-- 自动生成dao,mapper-->
    <!-- 4.配置扫描Dao接口包，动态实现Dao接口，注入到spring容器中 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!-- 给出需要扫描Dao接口包 -->
        <property name="basePackage" value="com.whut.dao"/>
        <!-- 注入sqlSessionFactory -->
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    </bean>



    <!--自动扫描-->
    <context:component-scan base-package="com.whut"/>


    <!-- 配置事务-->
    <!-- 5.配置事务管理器 -->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>
    <!-- 6.开启事务注解-->
    <tx:annotation-driven></tx:annotation-driven>

</beans>

3.Log4j属性文件配置

log4j.properties

log4j.rootLogger=DEBUG, stdout

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

4.创建测试表

创建的还是昨天的那张表

DDL信息

5.创建对应的实体类

 UserInfo.java 采用getterAndsetter方法自动生成

package com.whut.bean;

/**
 * ClassName: UserInfo <br/>
 * Description: <br/>
 * date: 2019/7/12 9:40<br/>
 *
 * @author a8243<br />
 * @since JDK 1.8
 */
public class UserInfo {


    private int id;
    private String username;
    private  String password;

    public UserInfo(){

    }
    public int getId() {
        return id;
    }

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

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "UserInfo{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

6.创建dao接口

	IUserInfoDao:该类存放对数据库操作接口

package com.whut.dao;


import com.whut.bean.UserInfo;

import java.util.List;

/**
 * ClassName: IUserInfoDao <br/>
 * Description: <br/>
 * date: 2019/7/12 9:42<br/>
 *
 * @author a8243<br />
 * @since JDK 1.8
 */
public interface IUserInfoDao {
    List<UserInfo> findAll();
    void save(UserInfo userInfo);
    void delete(int id);
    void update(UserInfo userInfo);
}

7.创建服务接口和实现类

package com.whut.service;

import com.whut.bean.UserInfo;

import java.util.List;

/**
 * ClassName: IUserInfoService <br/>
 * Description: <br/>
 * date: 2019/7/12 10:19<br/>
 *
 * @author a8243<br />
 * @since JDK 1.8
 */
public interface IUserInfoService {
     List<UserInfo> findAll();
     void save(UserInfo userInfo);
     void delete(int id);
     void update(UserInfo userInfo);
}

package com.whut.service.impl;

import com.whut.bean.UserInfo;
import com.whut.dao.IUserInfoDao;
import com.whut.service.IUserInfoService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * ClassName: UserInfoServiceImpl <br/>
 * Description: <br/>
 * date: 2019/7/12 10:21<br/>
 *
 * @author a8243<br />
 * @since JDK 1.8
 */

@Service("UserInfoService")
public class UserInfoServiceImpl implements IUserInfoService {

    @Autowired
    IUserInfoDao userInfoDao;

    @Override
    public List<UserInfo> findAll() {
        return userInfoDao.findAll();

    }

    @Override
    public void save(UserInfo userInfo) {
          userInfoDao.save(userInfo);
    }

    @Override
    public void delete(int id) {
         userInfoDao.delete(id);
    }

    @Override
    public void update(UserInfo userInfo) {
        userInfoDao.update(userInfo);
    }
}

8.创建mapper中的.xml文件完成增删改查

UserInfoMapper.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="com.whut.dao.IUserInfoDao" >
    <select id="findAll" resultType="com.whut.bean.UserInfo">
        select * from userinfo
    </select>

    <insert id="save" parameterType="com.whut.bean.UserInfo">
        insert into userinfo (id,username,password) values(#{id},#{username},#{password})
    </insert>

    <update id="update" parameterType="com.whut.bean.UserInfo">
        update userinfo set username=#{username},password=#{password} where id = #{id}
    </update>

    <delete id="delete" parameterType="_int">
        delete from userinfo where id = #{id}
    </delete>
</mapper>

4.Spring-mvc整合

#####1.配置spring-mvc.xml文件

<?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:mvc="http://www.springframework.org/schema/mvc"
       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/beans
      http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
      http://www.springframework.org/schema/mvc
      http://www.springframework.org/schema/mvc/spring-mvc-4.3.xsd
      http://www.springframework.org/schema/context
      http://www.springframework.org/schema/context/spring-context-4.3.xsd
      http://www.springframework.org/schema/aop
      http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
      http://www.springframework.org/schema/tx
      http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">

    <!-- 1.注解扫描位置-->
    <context:component-scan base-package="com.whut.controller" />

    <!-- 2.配置映射处理和适配器-->
    <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping"/>
    <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"/>

    <!-- 3.视图的解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/jsp/" />
        <property name="suffix" value=".jsp" />
    </bean>
</beans>

2.配置web.xml文件

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">

  <!-- 配置加载类路径的配置文件 -->
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath*:applicationContext.xml</param-value>
  </context-param>

  <!-- 配置监听器 -->
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
  <listener>
    <listener-class>org.springframework.web.context.request.RequestContextListener</listener-class>
  </listener>

  <!-- 解决中文乱码过滤器 -->
  <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>
  </filter>
  <filter-mapping>
    <filter-name>characterEncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

  <!-- 前端控制器（加载classpath:spring-mvc.xml 服务器启动创建servlet） -->
  <servlet>
    <servlet-name>dispatcherServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <!-- 配置初始化参数，创建完DispatcherServlet对象，加载springmvc.xml配置文件 -->
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:spring-mvc.xml</param-value>
    </init-param>
    <!-- 服务器启动的时候，让DispatcherServlet对象创建 -->
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>dispatcherServlet</servlet-name>
    <url-pattern>*.do</url-pattern>
  </servlet-mapping>

</web-app>

5.前端实现

1.建立jsp页面

allUser.jsp

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

<html>
<head>
    <title>user列表</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- 引入 Bootstrap -->
    <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
<div class="container">
    <div class="row clearfix">
        <div class="col-md-12 column">
            <div class="page-header">
                <h1>
                    基于SSM框架的管理系统：简单实现增、删、改、查。
                </h1>
            </div>
        </div>
    </div>

    <div class="row clearfix">
        <div class="col-md-12 column">
            <div class="page-header">
                <h1>
                    <small>用户列表 —— 显示所有用户</small>
                </h1>
            </div>
        </div>
    </div>
    <div class="row">
        <div class="col-md-4 column">
            <a class="btn btn-primary" href="${pageContext.request.contextPath}/user/toAddUser.do">新增</a>
        </div>
    </div>
    <div class="row clearfix">
        <div class="col-md-12 column">
            <table class="table table-hover table-striped">
                <thead>
                <tr>
                    <th>id</th>
                    <th>用户名</th>
                    <th>密码</th>
                    <th>操作</th>
                </tr>
                </thead>
                <tbody>
                <c:forEach items="${users}" var="userInfo">
                    <tr>
                        <td>${userInfo.id}</td>
                        <td>${userInfo.username}</td>
                        <td>${userInfo.password}</td>
                        <td>
                            <a href="${pageContext.request.contextPath}/user/toUpdate.do?id=${userInfo.id}&username=${userInfo.username}&password=${userInfo.password}">更改</a> |
                            <a href="${pageContext.request.contextPath}/user/delete.do?id=${userInfo.id}">删除</a>
                        </td>
                    </tr>
                </c:forEach>
                </tbody>
            </table>
        </div>
    </div>
</div>

addUser.jsp

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

<html>
<head>
    <title>新增用户</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- 引入 Bootstrap -->
    <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
<div class="container">
    <div class="row clearfix">
        <div class="col-md-12 column">
            <div class="page-header">
                <h1>
                    基于SSM框架的管理系统：简单实现增、删、改、查。
                </h1>
            </div>
        </div>
    </div>

    <div class="row clearfix">
        <div class="col-md-12 column">
            <div class="page-header">
                <h1>
                    <small>新增用户</small>
                </h1>
            </div>
        </div>
    </div>
    <form action="${pageContext.request.contextPath}/user/save.do"
              method="post">
        用&nbsp;&nbsp;户&nbsp;&nbsp;id：<input type="text" name="id"><br><br><br>
        用户姓名：<input type="text" name="username"><br><br><br>
        用户密码：<input type="text" name="password"><br><br><br>
        <input type="submit" value="添加" >
    </form>

</div>

updateUser.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
         pageEncoding="UTF-8" isELIgnored="false"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>修改论文</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- 引入 Bootstrap -->
    <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
<div class="container">
    <div class="row clearfix">
        <div class="col-md-12 column">
            <div class="page-header">
                <h1>
                    基于SSM框架的管理系统：简单实现增、删、改、查。
                </h1>
            </div>
        </div>
    </div>

    <div class="row clearfix">
        <div class="col-md-12 column">
            <div class="page-header">
                <h1>
                    <small>修改用户</small>
                </h1>
            </div>
        </div>
    </div>

    <form action="${pageContext.request.contextPath}/user/update.do"
          method="post">
        <input type="hidden" name="id" value="${id}"/>
        用户姓名：<input type="text" name="username" value="${username}"/>
        用户密码：<input type="text" name="password" value="${password}"/>
        <input type="submit" value="提交" />
    </form>
</div>

2.建立controller类

UserInfoController.java

package com.whut.controller;

import com.whut.bean.UserInfo;
import com.whut.service.IUserInfoService;
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.servlet.ModelAndView;

import java.util.List;

/**
 * ClassName: UserInfoController <br/>
 * Description: <br/>
 * date: 2019/7/12 15:12<br/>
 *
 * @author a8243<br />
 * @since JDK 1.8
 */

@Controller
@RequestMapping("user")
public class UserInfoController {

    @Autowired
    IUserInfoService userInfoService;

    @RequestMapping("findAll.do")
    public ModelAndView findAll(){
        List<UserInfo> users = userInfoService.findAll();
        ModelAndView mv = new ModelAndView();
        mv.addObject("users",users);
        mv.setViewName("allUser");
        return mv;
    }


    /**
    * @Description: 跳转到addUser界面
     * @Param:  * @param null
     * @return:
     * @Author: Mr.Zhu
     * @Date: 2019/7/12
     */
    @RequestMapping("toAddUser.do")
    public ModelAndView toAddUser(){
        ModelAndView mv = new ModelAndView();
        mv.setViewName("addUser");
        return mv;
    }


    /**
    * @Description: 跳转到更新页面
     * @Param:  * @param null
     * @return:
     * @Author: Mr.Zhu
     * @Date: 2019/7/12
     */
    @RequestMapping("toUpdate.do")
    public  ModelAndView toUpdate(@RequestParam("id") int id, @RequestParam("username") String username, @RequestParam("password") String password){


        ModelAndView mv = new ModelAndView();
        mv.addObject("id",id);
        mv.addObject("username",username);
        mv.addObject("password",password);
        mv.setViewName("updateUser");
        return mv;
    }


    /**
    * @Description: 新增数据
     * @Param:  * @param null
     * @return:
     * @Author: Mr.Zhu
     * @Date: 2019/7/12
     */
    @RequestMapping("save.do")
    public  ModelAndView save(@RequestParam("id") int id,@RequestParam("username") String username, @RequestParam("password") String password){
      UserInfo userInfo = new UserInfo();
      userInfo.setId(id);
      userInfo.setUsername(username);
      userInfo.setPassword(password);
      userInfoService.save(userInfo);
      return new ModelAndView("redirect:/user/findAll.do");
    }


    /**
    * @Description: 更新数据
     * @Param:  * @param null
     * @return:
     * @Author: Mr.Zhu
     * @Date: 2019/7/12
     */
    @RequestMapping("update.do")
    public  ModelAndView update(int id, String username, String password){
        UserInfo userInfo = new UserInfo();
        userInfo.setId(id);
        userInfo.setUsername(username);
        userInfo.setPassword(password);
        userInfoService.update(userInfo);
        return new ModelAndView("redirect:/user/findAll.do");
    }



    /**
    * @Description: 删除数据
     * @Param:  * @param null
     * @return:
     * @Author: Mr.Zhu
     * @Date: 2019/7/12
     */
    @RequestMapping("delete.do")
    public ModelAndView  delete(@RequestParam("id") int id){
        userInfoService.delete(id);
        return new ModelAndView("redirect:/user/findAll.do");
    }
}