Java项目实战-查询用户列表接口服务搭建

概述

这里通过设计一个对用户进行增删改查的接口服务，来练习java项目工程化、Spring框架、Mybatis框架的实际应用

本项目目录

上一节初始化项目，已经controller层了，下方新建包：pojo、mapper、service

pojo:所有的实体类都放这里

mapper:所有的mapper接口都放这里(可以理解为数据访问层)

service:具体的业务逻辑处理写这里(curd)

创建实体类

package com.mxf.monkey.pojo;
import lombok.Data;
import lombok.AllArgsConstructor;
import lombok.NoArgsConstructor;
 
 
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
/*
* 定义了一个用户实体类
* 包含getter、setter等构造方法
* */
    private int user_id;
    private String user_name;
    private String user_sex;
}

根据实体类创建和初始化数据

定义一个查询用户列表的mapper接口

package com.mxf.monkey.mapper;
 
import com.mxf.monkey.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
 
 
import java.util.List;
 
 
@Repository
@Mapper
public interface UserMapper {
    //定义了一个查询用户列表的方法，返回list类型
    ListqueryUserList();
 
}

写mapper接口对应的mapper映射文件

"1.0" encoding="UTF-8" ?>
mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.mxf.monkey.mapper.UserMapper">
    <select id="queryUserList" resultType="User">
        select * from monkey.monkey_user
    select>
mapper>

pom文件中更新mybatis依赖

其他的依赖如sping、mysql等在初始化项目时已经建了

<?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>2.7.16</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.mxf</groupId>
	<artifactId>monkey</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>monkey</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-thymeleaf</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
 
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-devtools</artifactId>
			<scope>runtime</scope>
			<optional>true</optional>
		</dependency>
		<!--MyBatis-Spring依赖-->
		<dependency>
			<groupId>org.mybatis.spring.boot</groupId>
			<artifactId>mybatis-spring-boot-starter</artifactId>
			<version>2.1.1</version>
		</dependency>
		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis</artifactId>
			<version>3.5.7</version>
		</dependency>
		<!--数据库连接依赖-->
		<dependency>
			<groupId>com.mysql</groupId>
			<artifactId>mysql-connector-j</artifactId>
			<scope>runtime</scope>
		</dependency>
		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
        <dependency>
            <groupId>org.xmlunit</groupId>
            <artifactId>xmlunit-core</artifactId>
        </dependency>
 
    </dependencies>
 
	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>
 
</project>

mybatis映射配置及Spring数据库配置

上边定义了mapper接口和mapper映射文件，那么怎么把2个联系起来，就需要通过在application.yml中进行配置

server:
  port: 8080
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/你的表名?characterEncoding=utf-8&serverTimezone=Asia/Shanghai
    username: 数据库账号
    password: 数据库密码
    driver-class-name: com.mysql.cj.jdbc.Driver
mybatis:
  type-aliases-package: com.mxf.monkey.pojo
  mapper-locations: classpath:mybatis/mapper/*.xml

创建service服务

package com.mxf.monkey.service;
 
import com.mxf.monkey.mapper.UserMapper;
import com.mxf.monkey.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
 
import java.util.List;
 
@Service
public class UserService {
    @Autowired
    UserMapper userMapper;
    public List queryUserList(){
        //导入UserMapper中的queryUserList方法，并调用
        return userMapper.queryUserList();
    }
 
}

创建controller对应接口

package com.mxf.monkey.controller;
 
import com.mxf.monkey.pojo.User;
import com.mxf.monkey.service.UserService;
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
    UserService userService;
 
    @GetMapping("/queryUserList")
    public List queryUserList() {
        return userService.queryUserList();
    }
}

运行服务

测试接口