第十四节:SpringBoot使用JdbcTemplate访问操作数据库基本用法

Spring对数据库的操作在jdbc上面做了深层次的封装，使用spring的注入功能，可以把DataSource注册到JdbcTemplate之中。

JdbcTemplate在Spring-jdbc包下面,还需要Spring-tx包支持,里面包含事务和异常控制.

建一个rumenz_springboot库

• 创建user表

create table user(
  id int primary key auto_increment,
  name varchar(100) not null default '',
  domain varchar(100) not null default ''
)engine=innodb default charset=utf8;

加入pom的依赖

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
	<groupId>mysql</groupId>
	<artifactId>mysql-connector-java</artifactId>
	<scope>runtime</scope>
</dependency>

SpringBoot配置文件

• application.properties

spring.datasource.url=jdbc:mysql://localhost:3306/rumenz_springboot
spring.datasource.username=root
spring.datasource.password=root1234
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

创建User实体类

@Builder
@Data
@AllArgsConstructor
public class User  implements RowMapper {
    private Integer id;
    private String name;
    private String domain;

    @Override
    public Object mapRow(ResultSet rs, int rowNum) throws SQLException {
        User user=new User();
        user.setId(rs.getInt("id"));
        user.setName(rs.getString("name"));
        user.setDomain(rs.getString("domain"));
        return user;
    }
}

Service接口

• UserService.java

package com.rumenz.lession14.controller.service;

import com.rumenz.lession14.controller.entity.User;

import java.util.List;

/**
 * @className: UserService
 * @description: TODO 类描述
 * @author: 入门小站 rumenz.com
 * @date: 2021/12/13
 **/
public interface UserService {
    Integer save(User user);
    List<User> list();
    Integer update(User user);

    Integer batchSave();
}

Service接口实现类

• UserServiceImpl.java

package com.rumenz.lession14.controller.service.Impl;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.json.JsonMapper;
import com.rumenz.lession14.controller.entity.User;
import com.rumenz.lession14.controller.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;

/**
 * @className: UserServiceImpl
 * @description: TODO 类描述
 * @author: 入门小站 rumenz.com
 * @date: 2021/12/13
 **/

@Service
public class UserServiceImpl implements UserService {
    @Autowired
    private JdbcTemplate jdbcTemplate;

    @Override
    public Integer save(User user) {
        int reint = jdbcTemplate.update("insert into user(name,domain) values (?,?)", user.getName(), user.getDomain());
        return reint;
    }

    @Override
    public Integer batchSave() {
        String sql="insert into user(name,domain) values(?,?)";
        List<Object[]> par=new ArrayList<>();
        for (int i = 0; i < 10; i++) {
            String[] s=new String[2];
            s[0]="入门小站"+i;
            s[1]="https://rumenz.com/"+i;
            par.add(s);
        }
        int[] ints = jdbcTemplate.batchUpdate(sql, par);
        System.out.println(ints.toString());
        return 0;
    }

    @Override
    public List<User> list() {
        //User实现RowMapper接口，实现接口里的mapRow方法。
        List<User> list = jdbcTemplate.query("select * from user",new User());
        return list;
    }

    @Override
    public Integer update(User user) {
        Integer reint=jdbcTemplate.update("update user set name=?,domain=? where id=?", user.getName(),user.getDomain(),user.getId());
        //
        return reint;
    }


}

Controller测试

• RumenzController.java

package com.rumenz.lession14.controller;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.rumenz.lession14.controller.entity.User;
import com.rumenz.lession14.controller.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

/**
 * @className: RumenzController
 * @description: TODO 类描述
 * @author: 入门小站 rumenz.com
 * @date: 2021/12/13
 **/
@RestController
@RequestMapping("/rumenz")
public class RumenzController {


    @Autowired
    private UserService userService;


    //添加数据
    @GetMapping("/save")
    public String save(){
        User user=User.builder().name("入门小站").domain("https://rumenz.com").build();
        Integer reint = userService.save(user);
        return reint.toString();
    }

    //批量添加数据
    @GetMapping("/batchSave")
    public String batchSave(){
        Integer reint = userService.batchSave();
        return reint.toString();
    }

    //查询数据
    @GetMapping("/list")
    public String list() throws JsonProcessingException {
        List<User> list = userService.list();
        ObjectMapper objectMapper=new ObjectMapper();
        String val = objectMapper.writeValueAsString(list);
        return val;
    }
    //更新数据
    @GetMapping("/update")
    public String update() throws JsonProcessingException {
        User user=User.builder().id(1).name("入门小站-修改").domain("https://tooltt.com").build();
        Integer reint = userService.update(user);
        return reint.toString();
    }

}

总结

常用CURD操作大致使用以下三个方法:

• 1.execute方法，用于直接执行SQL语句
• 2.update方法，用户新增修改删除操作
• 3.query方法，用于查询方法

本小结源码地址:

• GitHub:https://github.com/mifunc/springboot/tree/main/lession14
• Gitee:https://gitee.com/rumenz/springboot/tree/master/lession14
• https://rumenz.com/rumenbiji/springboot-jdbctemplate.html

介绍

• 我的博客 https://rumenz.com/ ,
• 我的工具箱 https://tooltt.com/