教你用springboot连接mysql并实现增删改查

create database mybatis;

use mybatis;
create table user2(
id integer not null primary key,
name varchar(20) not null,
pwd varchar(10) not null,
perms varchar(100) null)

package com.kuang.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.WEB.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import java.util.Map;
import java.util.List;
import java.lang.*;
import java.util.Scanner;


@RestController
public class JDBCController {

    @Autowired
    JdbcTemplate jdbcTemplate;

    //查询数据库的所有信息
    //没有实体类，数据库里的东西，怎么获取？ Map

    //查
    @GetMapping("/userList")
    public List<Map<String,Object> > userList(){
        String sql="select * from mybatis.user2";
        List<Map<String,Object>> list_maps=jdbcTemplate.queryForList(sql);
        return list_maps;
    }


    //增
    @GetMapping("/addUser")
    public String addUser(){
        String sql="insert into mybatis.user2(id,name,pwd,perms) values(3,'xiaoming','123456','NULL')";
        jdbcTemplate.update(sql);
        return "add-ok";
    }

    //改
    @GetMapping("updateUser/{id}/{name}/{pwd}")
    public String updateUser(@PathVariable("id") int id,@PathVariable("name") String name,@PathVariable("pwd") String pwd){
        String sql="update mybatis.user2 set  name=?,pwd=?  where  id="+id;

        //封装Object
        Object[] objects = new Object[2];
        objects[0]=name;
        objects[1]=pwd;

        jdbcTemplate.update(sql,objects);
        return "update-ok";
    }

    //删
    @GetMapping("/deleteUser/{id}")
    public String deleteUser(@PathVariable("id") int id){
        String sql="delete from mybatis.user2 where id=?";
        jdbcTemplate.update(sql,id);
        return "delete-ok";
    }
}

spring:
  datasource:
    username: root
    passWord: liding
    url: jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.jdbc.Driver

package com.kuang;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class Springboot04DataApplication {

    public static void main(String[] args) {
        SpringApplication.run(Springboot04DataApplication.class, args);
    }

}

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.5</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.kuang</groupId>
    <artifactId>springboot-04-data</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot-04-data</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- JDBC-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <!-- MySQL-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.4.5</version>
            </plugin>
        </plugins>
    </build>
</project>

1）<plugin> </plugin>之间的语句爆红

2）建立项目时勾选以下模块
spring web
JDBC api
mysql Driver