springboot与mybatis连接数据库操作

一导入依赖：

<?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>2.5.2</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.yang</groupId>
    <artifactId>spingboot-demo-04</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>spingboot-demo-04</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-data-jdbc</artifactId>
        </dependency>

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

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>6.0.6</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </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>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

2 数据库配置：

spring:
datasource:
username: root
password: mysql
#url: jdbc:mysql://locahost:3306/mybatis?useUnicode=true&chracterEncoding=utf-8&useSSL=false&serverTimezone=GMT
url: jdbc:mysql://localhost:3306/mybatis?useUnicode=true&chracterEncoding=utf-8
driver-class-name: com.mysql.cj.jdbc.Driver

##下面这两个配置，可以在每次连接的时候判断一些连接是否有效
#spring.datasource.druid.test-on-borrow=true
#spring.datasource.druid.test-while-idle=true

3 打印一下信息：

package com.yang.spingbootdemo04;

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;

@SpringBootTest
class SpingbootDemo04ApplicationTests {
    
    

    @Autowired
    DataSource dataSource;

    @Test
    void contextLoads() throws SQLException {
    
    
        //查看一下默认的数据源
        System.out.println(dataSource.getClass());


        //获取连接
        Connection connection = dataSource.getConnection();
        System.out.println(connection);

        //关闭数据源
        connection.close();
    }

}

4 写一个简单的controller

package com.yang.spingbootdemo04.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.List;
import java.util.Map;

@RestController
public class JDBCController {
    
    
    @Autowired
    JdbcTemplate jdbcTemplate;

    //查询数据库的所以信息
    //现在没有实体类
@GetMapping("/userList")
    public List<Map<String,Object>> userList(){
    
    
        String sql = "select * from user";
    System.out.println("=============================");
        List<Map<String, Object>> maps = jdbcTemplate.queryForList(sql);
        return  maps;
    }

    @GetMapping("/addUser")
    public String addUser(){
    
    
    String sql = "insert into user(id,name,pwd) values(101,'yang','xxxxxxxxxxx')";
        jdbcTemplate.update(sql);
        String s = "update-ok";
        return s;
    }

    @GetMapping("/updateUser/{id}")
    public String updateUser(@PathVariable("id") int id){
    
    
        String sql = "update user set name = ?, pwd=? where id= "+id;
//封装
        Object[] objects = new Object[2];
        objects[0] = "小明2";
        objects[1] = "zxxxxxxxxxxxx";

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

    @GetMapping("/deleteUser/{id}")
    public String deleteUser(@PathVariable("id") int id){
    
    
        //String sql = "insert into user(id,name,pwd) values()";
        String sql = "delete from user where id = 1";
        jdbcTemplate.update(sql);
        String s = "deleteUser-ok";
        return s;
    }

}

package com.yang.spingbootdemo04.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.List;
import java.util.Map;

@RestController
public class JDBCController {
@Autowired
JdbcTemplate jdbcTemplate;

//查询数据库的所以信息
//现在没有实体类

@GetMapping("/userList")
public List<Map<String,Object>> userList(){
String sql = “select * from user”;
System.out.println("=============================");
List<Map<String, Object>> maps = jdbcTemplate.queryForList(sql);
return maps;
}

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@GetMapping("/addUser")
public String addUser(){
String sql = "insert into user(id,name,pwd) values(101,'yang','xxxxxxxxxxx')";
    jdbcTemplate.update(sql);
    String s = "update-ok";
    return s;
}

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

//封装
Object[] objects = new Object[2];
objects[0] = “小明2”;
objects[1] = “zxxxxxxxxxxxx”;

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

@GetMapping("/deleteUser/{id}")
public String deleteUser(@PathVariable("id") int id){
    //String sql = "insert into user(id,name,pwd) values()";
    String sql = "delete from user where id = 1";
    jdbcTemplate.update(sql);
    String s = "deleteUser-ok";
    return s;
}

}

5 结果：
查询

删除：