Springboot+mybatis+jsp实现简单的增删改查（详细步骤）

一、环境搭建

1.创建一个springboot项目(勾选web)

2.导入依赖

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        

        <!--数据库连接池-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.12</version>
        </dependency>

        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-api</artifactId>
            <version>RELEASE</version>
        </dependency>

        <dependency>
            <groupId>jstl</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <dependency>
            <groupId>org.apache.tomcat.embed</groupId>
            <artifactId>tomcat-embed-jasper</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
        </dependency>

3.创建数据库表并插入数据

二、代码编写

1.全局配置文件编写，application.yml配置信息

#配数据源信息
spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/spring-mybatis?serverTimezone=Asia/Shanghai
    username: root
    password: 625814
  mvc: #配置jsp映射路径 return "index" /index.jsp
    view:
      prefix: /
      suffix: .jsp
  main:
    allow-circular-references: true

mybatis:
  type-aliases-package: com.zyl.pojo   #别名
  mapper-locations:  classpath:/mapper/*Mapper.xml 

2.全查功能实现

(1). 封装实体类

package com.zyl.pojo;

public class Student {

    private Integer id;
    private String name;
    private Integer age;
    private String gender;

    public Student() {
    }

    public Student(Integer id, String name, Integer age, String gender) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.gender = gender;
    }

    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;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", gender='" + gender + '\'' +
                '}';
    }
}

(2). 书写dao层

package com.zyl.dao;

import com.zyl.pojo.Student;
import org.apache.ibatis.annotations.Mapper;

import java.util.List;

@Mapper
public interface StudentDao {

    //全部查询
    public List<Student>  queryAll();
}

(3). mapper映射文件

<?xml version="1.0" encoding="UTF8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.zyl.dao.StudentDao">
        <select id="queryAll" resultType="student">
            select * from student
        </select>
</mapper>

(4). service接口

package com.zyl.service;

import com.zyl.pojo.Student;

import java.util.List;

public interface StudentService {

    //全部查询
    public List<Student> queryAll();
}

(5). service接口实现

package com.zyl.service;

import com.zyl.dao.StudentDao;
import com.zyl.pojo.Student;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class StudentServiceImpl implements StudentService{
    @Autowired
    private StudentDao studentDao;

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

(6). controller

package com.zyl.controller;

import com.zyl.pojo.Student;
import com.zyl.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;

import java.util.List;

@Controller
@RequestMapping("/student")
public class StudentController {
    @Autowired
    private StudentService studentService;

    @RequestMapping("/queryAll")
    public String queryAll(Model model){
        List<Student> list = studentService.queryAll();
        model.addAttribute("list",list);
        return "showAll";
    }
}

(7). jsp编写

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<center>
    <h3>学生信息展示页面</h3>
    <table border="1" width="600px">
        <tr>
            <td>学生编号</td>
            <td>学生姓名</td>
            <td>学生性别</td>
            <td>学生年龄</td>
            <td>学生操作</td>
        </tr>
        <c:forEach items="${list}" var="a">
            <tr>
                <td>${a.id}</td>
                <td>${a.name}</td>
                <td>${a.gender}</td>
                <td>${a.age}</td>
             
            </tr>
        </c:forEach>
    </table>
</center>
</body>
</html>

3. 根据ID删除

(1). dao接口

    //根据id删除学生信息
    public void deleteById(Integer id);

(2). mapper映射文件

    <delete id="deleteById" parameterType="Integer">
        delete  from student where id=#{id}
    </delete>

(3). service接口

    //根据id删除学生信息
    public void deleteById(Integer id);

(4). service接口实现

 @Override
    public void deleteById(Integer id) {
        try{
            studentDao.deleteById(id);
        }catch (Exception e){
            throw new RuntimeException("根据id删除有异常");
        }

    }

(5). controller

    @RequestMapping("/deleteById")
    public String deleteById(Integer id){
        try{
            studentService.deleteById(id);
            return "redirect:/student/queryAll";
        }catch (Exception e){
            return "error";
        }
    }

(6). jsp代码

<td>
     <a href="${pageContext.request.contextPath}/student/deleteById?id=${a.id}">删除</a>
</td>

4、添加学生信息

(1). dao层

 //添加学生信息
    public void insertStudent(Student student);

(2). mapper映射文件

 <insert id="insertStudent" parameterType="student">
        INSERT INTO student(name,age,gender) values(#{name},#{age},#{gender})
    </insert>

(3). service接口

  //添加学生信息
    public void insertStudent(Student student);

(4).service接口实现

    @Override
    public void insertStudent(Student student) {
        try{
            studentDao.insertStudent(student);
        }catch (Exception e){
            throw new RuntimeException("添加有异常");
        }
    }

(5). controller

 @RequestMapping("/add")
    public String add(){
        return "add";
    }

    @RequestMapping("/addStudent")
    public String addStudent(Student student){
        try{
            studentService.insertStudent(student);
            return "redirect:/student/queryAll";
        }catch (Exception e){
            return "error";
        }
    }

(6). jsp代码

<%--
  Created by IntelliJ IDEA.
  User: lenovo
  Date: 2022/5/15
  Time: 23:39
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>添加</title>
</head>
<body>
    <h3>学生信息添加</h3>
    <form action="${pageContext.request.contextPath}/student/addStudent">
        学生姓名:<input type="text" name="name">
        学生年龄:<input type="text" name="age">
        学生性别:<input type="radio" name="gender" value="男" checked="checked">男<br>
                 <input type="radio" name="gender" value="女">女
       <br>
        <input type="submit" value="提交">
    </form>
</body>
</html>

在showAll.jsp加上（其实此处不要写成这样 controller中add可以去掉 这里直接href跳转到add页面）

  <a href="${pageContext.request.contextPath}/student/add">添加</a>

5、修改学生信息

(1). 思路

(2). 数据回显

A. dao接口

  //根据ID查询学生信息
    public Student selectById(Integer id);

B.mapper映射文件

   <!--根据ID查询-->
    <select id="selectById" parameterType="Integer" resultType="student">
        select * from student where id=#{id}
    </select>

C.service接口

    //根据ID查询学生信息
    public Student queryById(Integer id);

D.service接口实现

    @Override
    public Student queryById(Integer id) {
        return studentDao.selectById(id);
    }

E.controller

   //根据ID查询学生信息
    @RequestMapping("/queryById")
    public String queryById(Integer id, ModelMap mm){
        Student student = studentService.queryById(id);
        mm.addAttribute("student",student);
        //跳转到修改页面，进行数据回显
        return "update";
    }

F.jsp代码

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>添加</title>
</head>
<body>
<center>
    <h3>学生信息修改页面</h3>
    <form action="${pageContext.request.contextPath}/student/changeStudent">
        <input type="hidden" name="id" value="${student.id}">
        学生姓名:<input type="text" name="name" value="${student.name}"><br>
        学生年龄:<input type="text" name="age" value="${student.age}"><br>
        学生性别:<input type="radio" name="gender" value="男"
                    <c:if test="${student.gender=='男'}">checked="checked"</c:if>
    >男
        <input type="radio" name="gender" value="女"
               <c:if test="${student.gender=='女'}">checked="checked"
        </c:if>
        >女
        <br>
        <input type="submit" value="修改">
    </form>
</center>
</body>
</html>

(3).数据修改

A. dao层

 //修改学生
    public void updateStudent(Student student);

B. mapper映射文件

    <update id="updateStudent" parameterType="student">
        update student set name=#{name},age=#{age},gender=#{gender} where id=#{id}
    </update>

C. service接口

//修改学生
    public void updateStudent(Student student);

D. service接口实现

 @Override
    public void updateStudent(Student student) {
        try{
            studentDao.updateStudent(student);
        }catch (Exception e){
            throw new RuntimeException("修改数据异常");
        }
    }

E. controller

  //修改数据
    @RequestMapping("/changeStudent")
    public String changeStudent(Student student){
        try{
            studentService.updateStudent(student);
            return "redirect:/student/queryAll";
        }catch (Exception e){
            return "error";
        }
    }

F. jsp页面同回显页面

注意事项：

在多模块开发下可能会碰到页面404的情况 打开 Edit Configrations 修改下面箭头标记处 这样表示当前目录

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