Springboot整合mybatis试连接数据库
Web02成功案例分析
Springboot整合mybatis从而使用数据库试验，为员工管理系统配置数据库做准备，狂神B站有教程
2021-10-27
IDEA2021.2
java 8
mysql 8
项目步骤
这波是自己回来看都看不懂，先看一遍流程，然后照做
一、建立一个空的springboot项目，依赖不选也无所谓
二、闭着眼睛导依赖，pom.xml文件中dependencies标签包括的东西拿来把自己的替换掉
三、添加数据库，写配置文件application.properties，建表不急
四、往test目录下的Test类加代码，代码简陋有爆红应该无所谓，强迫症可自行加上（try,catch）的环绕，主要是测试能否与数据库建立连接，若连接成功会执行那两个打印的操作，慢慢来很难出错吧
如果报错就是没连上，根据报错检查配置文件，这步测试通不过就不用往后做了
五、正式开始写代码，看看项目结构（没有按照正常的mvc开发），照贴代码ing
六、启动，测试，结束
代码结构
数据库结构
测试连接
Web02ApplicationTests.java
package com.xie;
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 Web02ApplicationTests {
//DI注入数据源
@Autowired
DataSource dataSource;
@Test
public void contextLoads() throws SQLException {
//看一下默认数据源
System.out.println(dataSource.getClass());
//获得连接
Connection connection = dataSource.getConnection();
System.out.println(connection);
//关闭连接
connection.close();
}
}
Test强迫症版本
void contextLoads() {
System.out.println(dataSource.getClass());
Connection connection = null;
try {
connection = dataSource.getConnection();
} catch (SQLException e) {
e.printStackTrace();
}
System.out.println(connection);
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
测试结果
输出默认数据源，且获得连接，顺便打印该连接
CURD测试
一般springboot启动成功后，访问localhost:8080看到404就是可以继续了
localhost:8080/queryUserList
localhost:8080/addUser #以下操作均返回“ok”
localhost:8080/updateUser
localhost:8080/deleteUser
依赖文件
pom.xml
<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>4.0.0modelVersion>
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>2.6.7version>
<relativePath/>
parent>
<groupId>comgroupId>
<artifactId>vote01artifactId>
<version>0.0.1-SNAPSHOTversion>
<name>vote01name>
<description>vote01description>
<properties>
<java.version>1.8java.version>
properties>
<dependencies>
<dependency>
<groupId>org.mybatis.spring.bootgroupId>
<artifactId>mybatis-spring-boot-starterartifactId>
<version>2.1.1version>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-jdbcartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<scope>runtimescope>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<optional>trueoptional>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
plugin>
plugins>
build>
project>
配置文件
application.properties
(个人配置文件)
spring.datasource.username=root
spring.datasource.password=111111
spring.datasource.url=jdbc:mysql://localhost:3306/springboot?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
mybatis.type-aliases-package=com.xie.pojo
mybatis.mapper-locations=classpath:mybatis/mapper/*.xml
代码详情
User.java
package com.xie.pojo;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
private int id;
private String name;
private String pwd;
}
UserMapper.java
package com.xie.mapper;
import com.xie.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
import java.util.List;
@Mapper
@Repository
public interface UserMapper {
List<User> queryUserList();
int addUser (User user);
int updateUser(User user);
int deleteUser(int id);
}
UserController.java
package com.xie.controller;
import com.xie.mapper.UserMapper;
import com.xie.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;
@RestController
public class UserController {
@Autowired
private UserMapper userMapper;
@GetMapping("/queryUserList")
public List<User> queryUserList(){
List<User> userList = userMapper.queryUserList();
for (User user : userList){
System.out.println(user);
}
return userList;
}
@GetMapping("addUser")
public String addUser(){
userMapper.addUser(new User(106,"amao","123456"));
return "ok";
}
@GetMapping("updateUser")
public String updateUser(){
userMapper.updateUser(new User(106,"amao","000456"));
return "ok";
}
@GetMapping("deleteUser")
public String deleteUser(){
userMapper.deleteUser(106);
return "ok";
}
}
Web02Application.java
保持默认，不可更改
UserMapper.xml
DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.xie.mapper.UserMapper">
<select id="queryUserList" resultType="com.xie.pojo.User">
select * from user ;
select>
<insert id="addUser" parameterType="com.xie.pojo.User">
insert into user (id,name ,pwd) values (#{id},#{name},#{pwd})
insert>
<update id="updateUser" parameterType="com.xie.pojo.User">
update user set name = #{name},pwd=#{pwd} where id = #{id}
update>
<delete id="deleteUser" parameterType="int">
delete from user where id = #{id}
delete>
mapper>
mapper文件之间的相互对应，应该是因为namespace联系上的
数据库
use testdb;
create table user
(
id int not null
primary key,
name varchar(30) null,
pwd varchar(30) null
);
INSERT INTO exp_4.user (id, name, pwd) VALUES (102, 'b', '123456');
INSERT INTO exp_4.user (id, name, pwd) VALUES (103, 'b', '3456');
INSERT INTO exp_4.user (id, name, pwd) VALUES (104, 'c', '1256');
INSERT INTO exp_4.user (id, name, pwd) VALUES (105, 's', '123456');
INSERT INTO exp_4.user (id, name, pwd) VALUES (106, 'r', '1256');
INSERT INTO exp_4.user (id, name, pwd) VALUES (107, 'y', '123456');