SpringBoot连接PostgreSQL+MybatisPlus入门案例

项目结构

一、Java代码

pom.xml

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>jdservice</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>2.0.3.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
            <version>2.0.3.RELEASE</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.postgresql/postgresql -->
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>42.6.0</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.12</version>
        </dependency>
        <!--mybatis‐plus的springboot支持-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.1.0</version>
        </dependency>


    </dependencies>
</project>

controller层

package org.example.jd.controller;

import org.example.jd.pojo.TUser;
import org.example.jd.service.TUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@CrossOrigin(origins = "http://localhost:8080")
@RestController
public class UserController {

    @Autowired
    private TUserService tUserService;

    @PostMapping("/api/userLogin")
    public String login(@RequestBody TUser tUser) {
        // 实际业务逻辑处理
        String username = tUser.getUsername();
        String password = tUser.getPassword();

        // 这里可以进行用户名密码验证等操作
        System.out.println("========Login successful=====");
        System.out.println(username + "," + password);
        return "Login successful"; // 返回登录成功信息或者其他响应
    }

    @GetMapping("/api/getUserList")
    public List<TUser> getUserList() {
        List<TUser> tUserList = tUserService.getUserList();
        return tUserList;
    }


}

mapper层

package org.example.jd.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.example.jd.pojo.TUser;

public interface TUserMapper extends BaseMapper<TUser> { //参数为实体类

}

pojo层

package org.example.jd.pojo;

import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.time.LocalDate;

@Data
@AllArgsConstructor
@NoArgsConstructor
@TableName("tuser")   //指定数据库表
public class TUser {
    @TableId(value = "uid") //指定主键
    private int uid;
    private String username;
    private String password;
    private int age;
    private String gender;
    private LocalDate birthday;
    private String address;
}

service层

TUserService 

package org.example.jd.service;

import org.example.jd.pojo.TUser;

import java.util.List;

public interface TUserService {
    List<TUser> getUserList();
}

TUserServiceImp 

package org.example.jd.service;

import org.example.jd.mapper.TUserMapper;
import org.example.jd.pojo.TUser;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class TUserServiceImp implements TUserService {

    @Autowired
    private TUserMapper tUserMapper;
    @Override
    public List<TUser> getUserList() {
        return tUserMapper.selectList(null);
    }
}

Application启动类

package org.example.jd;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan("org.example.jd.mapper") //扫描mapper层
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

TUserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<!--namespace是mapper层对应的接口名-->
<mapper namespace="org.example.jd.mapper.TUserMapper">

    <!--id是mapper层对应的接口名中对应的方法名-->
<!--    <select id="myFindUserById" resultType="User">-->
<!--        select *-->
<!--        from tb_user-->
<!--        where id = #{id}-->
<!--    </select>-->
</mapper>

mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!--设置驼峰匹配，MybatisPlus默认开启驼峰匹配-->
    <!--    <settings>-->
    <!--        <setting name="mapUnderscoreToCamelCase" value="true"/>-->
    <!--    </settings>-->

</configuration>

application.yml配置文件

server:
  port: 8090
spring:
  datasource:
    url: jdbc:postgresql://localhost:5432/myjd
    username: postgres
    password: 123456
    driver-class-name: org.postgresql.Driver


#设置mybatis-plus
mybatis-plus:
  config-location: classpath:mybatis/mybatis-config.xml  #配置文件
  mapper-locations: classpath:mybatis/mapper/*.xml  #设置mapper层对应的接口对应的mapper.xml的路径
  type-aliases-package: org.example.jd.pojo  #设置别名，mapper.xml中resultType="org.example.jd.pojo.TUser"可省去包，即resultType="TUser"
  #开启自动驼峰映射，注意：配置configuration.map-underscore-to-camel-case则不能配置config-location，可写到mybatis-config.xml中
#  configuration:
#    map-underscore-to-camel-case: true

二、SQL

/*
 Navicat Premium Data Transfer

 Source Server         : myPgSQL
 Source Server Type    : PostgreSQL
 Source Server Version : 160003 (160003)
 Source Host           : localhost:5432
 Source Catalog        : myjd
 Source Schema         : public

 Target Server Type    : PostgreSQL
 Target Server Version : 160003 (160003)
 File Encoding         : 65001

 Date: 19/07/2024 22:15:18
*/


-- ----------------------------
-- Table structure for tuser
-- ----------------------------
DROP TABLE IF EXISTS "public"."tuser";
CREATE TABLE "public"."tuser" (
  "uid" int4 NOT NULL,
  "username" varchar(255) COLLATE "pg_catalog"."default",
  "age" int4,
  "gender" varchar(1) COLLATE "pg_catalog"."default",
  "birthday" date,
  "address" varchar(255) COLLATE "pg_catalog"."default",
  "password" varchar(255) COLLATE "pg_catalog"."default"
)
;

-- ----------------------------
-- Records of tuser
-- ----------------------------
INSERT INTO "public"."tuser" VALUES (1, 'jack', 24, '男', '2021-10-19', '深圳', '123');

-- ----------------------------
-- Primary Key structure for table tuser
-- ----------------------------
ALTER TABLE "public"."tuser" ADD CONSTRAINT "user_pkey" PRIMARY KEY ("uid");

三、运行

浏览器或者postman请求地址。

注意：浏览器只能测试get请求，如果有put、post、delete请使用postman测试。

http://localhost:8090/api/getUserList