SSM整合版本一之普通的CRUD

项目简介

• （1）项目的经典模块-CRUD功能
• （2）什么是CRUD
  CRUD：Create（ 创 建 ）Retrieve（查询）Update（更新）Delete（删除）
  使用的技术栈：ssm:SpringMVC+Spring+MyBatis
• 本篇为V1：
  V1 : ssm
  V2 : ssm+Ajax
  V3 : ssm+Ajax+bootstrap

SSM环境搭建参考V2版本

• 测试后台代码是否正确

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class TestUserService {
    private static final Logger log = Logger.getLogger(TestUserService.class.getName());
    @Autowired
    UserService userService;
    @Test
    public void test01() {
        List<User> list = userService.findAllUser();
        log.info("list"+list);

    }
}

• User

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

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

• UserServiceImpl（方法已写）

@Service
public class UserServiceImpl implements UserService {
    @Autowired
    UserDao userDao;

    @Override
    public void saveUser(User user) {
        userDao.save(user);
    }

    @Override
    public void deleteUser(int id) {
        userDao.deleteById(id);
    }

    @Override
    public int login(User u) {
        return 0;
    }

    @Override
    public List<User> findAllUser() {
        List<User> list = userDao.finAllUser();
        return list;
    }

    @Override
    public User findByUserId(int id) {
        return userDao.findById(id);

    }

    @Override
    public void updateUserById(User user) {
       userDao.update(user);
    }
}

• UserDao

    List<User> finAllUser();

    void save(User user);

    void deleteById(int id);

    void update(User user);

     User findById(int id);

• UserDao.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">
<!--        User findByName(String username);-->
<mapper namespace="cn.htl.dao.UserDao">
    <select id="finAllUser" resultType="user">
        select * from user order by id asc;
    </select>
    <insert id="save" parameterType="user">
        insert into user (username,password) values (#{username},#{password}) ;
    </insert>
    <delete id="deleteById" parameterType="int">
        delete from user where id =#{id};
    </delete>
    <update id="update" parameterType="user">
        update user set password = #{password} where id = #{id};
    </update>
    <select id="findById" parameterType="int" resultType="user">
        select * from user where id = #{id};
    </select>
</mapper>

Controller层：代码显示

• DepartmentController（方法已写）

@Controller
@RequestMapping("/user")
public class UserController {
    private static final Logger log = LoggerFactory.getLogger(UserController.class);
    @Autowired
    private UserService userService;

    @RequestMapping(path = "/list", method = RequestMethod.GET)
    public String list(Model model) {
        List<User> users = userService.findAllUser();
        log.info("list=" + users);
        model.addAttribute("users", users);
        return "list_user";
    }

    @RequestMapping(path = "/addUser", method = RequestMethod.GET)
    public String AddUser() {
        log.info("AddUser");
        return "add_user";
    }
    @RequestMapping(path = "/addUser", method = RequestMethod.POST)
    public String SaveUser(User user, Model model) {
        if (user.getUsername() != null && !"".equals(user.getUsername())) {
            userService.saveUser(user);
            log.info("AddUser" + user);
            return "redirect:/user/list";
        } else {
            model.addAttribute("error_msg","添加用户不能为空");
            return "forward:/error";
        }
    }

    @RequestMapping(path = "/deleteUser", method = RequestMethod.GET)
    public String DeleteUser(Integer id) {
        log.info("DeleteUser" + id);
        userService.deleteUser(id);
        return "redirect:/user/list";
    }
    @RequestMapping(path = "/updateUser", method = RequestMethod.GET)
    public String Update(Integer id,Model model) {
        log.info("UpdateUser"+id);
        User user = userService.findByUserId(id);
        model.addAttribute("user",user);
        return "update_user";
    }
    @RequestMapping(path = "/update", method = RequestMethod.POST)
    public String UpdateUser(User user) {
        log.info("UpdateUser  user"+user);
        userService.updateUserById(user);

        return "redirect:/user/list";
    }
}

前台页面代码

• add_user.jsp

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<form method="post" action="${pageContext.request.contextPath}/user/addUser">
    <input type="text" name="username"/><br/>
    <input type="text" name="password"/><br/>
    <input type="submit" value="保存"/><br/>
</form>

</body>
</html>

• list_user.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
${users}
<table border="1px" width="100%">
    <tr>
        <td>编号</td>
        <td>用户名</td>
        <td>密码</td>
        <td>操作</td>

    </tr>

    <c:forEach items="${users}" var="user">
        <tr>
            <td>${user.id}</td>
            <td>${user.username}</td>
            <td>${user.password}</td>
            <td><a href="${pageContext.request.contextPath}/user/deleteUser?id=${user.id}">删除</a>
                <a href="${pageContext.request.contextPath}/user/updateUser?id=${user.id}">修改</a></td>
        </tr>
    </c:forEach>
</table>
</body>
</html>

• update_user.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<form method="post" action="${pageContext.request.contextPath}/user/update">
    <input type="hidden" name="id" value="${user.id}" >

    <input type="text"  value="${user.username}" disabled="disabled"/><br/>
    <input type="text"  value="${user.password}" disabled="disabled"/><br/>
    <input type="text" name="password" value="${user.password}"/><br/>
    <input type="submit" value="修改密码"/><br/>
</form>
</body>
</html>

• form表单 不会将 标记为disabled="disabled"作为参数提交到后台
• 所以，必须增加一个type="hidden"的input标签

本文地址：https://blog.csdn.net/weixin_45114005/article/details/109259807