如何简单地实现一些接口SpringBoot 实现一些接口

（非正式，青春学习版）

你需要做哪些工作？

1、下载IDEA

2、配置好java的环境

3、配置到meavn环境，并把meavn的数据库改成国内镜像的数据库,如：阿里云等

4、新建一个project

4.1、Spring Initializr数据库

5、配置application.properties

目的是为了配置与数据库的连接和与mybatis的包配置等

代码：

#端口、路径、数据库端口、数据库名、数据库角色名、密码需要手动更改
server.port=8080
server.servlet.context-path=/
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/student?useUnicode=true&characterEncoding=UTF8&serverTimezone=PRC
spring.datasource.username=root
spring.datasource.password=admin

#根据自身情况需要改一下路径
#放sql语句的包和xml文件
mybatis.mapper-locations= classpath:mapping/*Mapper.xml
#放实体类的包
mybatis.type-aliases-package=com.example.test4_23_2.entity

6、向pom.xml中添加包

1. 在target包中点开pom.xml,在标签内加入要引入的包
2. mybait包
3. swagger包
4. 分页pagehelper包

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.4</version>
        </dependency>


        <!-- https://mvnrepository.com/artifact/io.springfox/springfox-swagger-ui -->
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger-ui</artifactId>
            <version>2.9.1</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/io.springfox/springfox-swagger-ui -->
        <dependency>
            <groupId>io.springfox</groupId>
            <artifactId>springfox-swagger2</artifactId>
            <version>2.9.1</version>
        </dependency>

        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.2.3</version>
        </dependency>

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

7、建一些必要的包
common为了建立一个公共类
config用户配置一些组件
controller用于实现接口
service用于被controller中调用实现服务
service中的serviceImpl继承service，用于实现service中的方法
service需要调用dao
dao需要调用mapping中的*mapper.xml
具体如图：

以其中一个为例代码如下：

1. common:Result:

package com.example.test4_23_2.common;

public class Result {
    private int code;
    private String msg;
    private Object data;

    public Result() {
    }

    public Result(int code, String msg, Object data) {
        this.code = code;
        this.msg = msg;
        this.data = data;
    }

    public Result(int code, String msg) {
        this.code = code;
        this.msg = msg;
    }

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public Object getData() {
        return data;
    }

    public void setData(Object data) {
        this.data = data;
    }
}

2. config:corsConfig:

package com.example.test4_23_2.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class CorsConfig implements WebMvcConfigurer {
    final String ORIGINS[]={"GET","POST","PUT","DELETE"};
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**").allowedOrigins("*").allowCredentials(false).allowedMethods(ORIGINS).maxAge(3600).allowedHeaders("*");
    }
}

swaggerConfig:

package com.example.test4_23_2.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.ApiInfoBuilder;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2;

@Configuration
@EnableSwagger2
public class SwaggerConfig {



        @Bean
        public Docket petApi() {
            return new Docket(DocumentationType.SWAGGER_2)
                    .apiInfo(apiInfo())
                    .select()
                    .apis(RequestHandlerSelectors.basePackage("com.example.test4_23_2.controller")) //指定提供接口所在的基包
                    .paths(PathSelectors.any())
                    .build();
        }

        /**
         * 该套 API 说明，包含作者、简介、版本、host、服务URL
         * @return
         */
        private ApiInfo apiInfo() {
            return new ApiInfoBuilder()
                    .title("demo api 说明")
                    .version("0.1")
                    .termsOfServiceUrl("localhost:8080/demo1/")
                    .description("demo api")
                    .build();
        }

    }

之上是类似于全局的，以下是为了实现某个具体功能的：
自下而上
mapping:
RoleMapper.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">
<mapper namespace="com.example.test4_23_2.dao.RoleDao">
    <resultMap id ="RoleResultMap" type="com.example.test4_23_2.entity.Role">
        <id property="id" jdbcType="INTEGER" column="role_id"></id>
        <result property="name" column="role_name" jdbcType="VARCHAR"></result>
        <result property="create_time" column="role_create_time" jdbcType="TIMESTAMP"></result>
        <result property="status" column="role_status" jdbcType="VARCHAR"></result>
        <result property="father_role" column="role_father_role" jdbcType="INTEGER"></result>
        <result property="describe" column="role_describe" jdbcType="VARCHAR"></result>
        <!--        一对多-->
        <collection property="privs" ofType="com.example.test4_23_2.entity.Priv">
            <id property="id" jdbcType="INTEGER" column="priv_id"></id>
            <result property="priv_name" column="priv_name" jdbcType="VARCHAR"></result>
            <result property="status" column="priv_status" jdbcType="VARCHAR"></result>
            <result property="priv_father_id" column="priv_father_id" jdbcType="INTEGER"></result>
            <result property="priv_describe" column="priv_describe" jdbcType="VARCHAR"></result>
            <result property="priv_href" column="priv_href" jdbcType="VARCHAR"></result>
            <result property="priv_sort" column="priv_sort" jdbcType="INTEGER"></result>
            <result property="priv_sign" column="priv_sign" jdbcType="INTEGER"></result>
        </collection>

    </resultMap>

    <!--    根据角色查询权限-->
    <select id="selectPrivByRoleName" parameterType="String" resultMap="RoleResultMap">
        SELECT
            r.*,p.priv_name,p.priv_href,p.priv_sign,p.priv_describe,p.priv_sort,p.`status` as priv_status
        FROM role r
                 LEFT JOIN priv_role pr on r.id=pr.priv_id
                 LEFT JOIN priv p on pr.priv_id=p.id
        WHERE r.`name`=#{rolename}
    </select>

    <select id="selectAllRole" resultMap="RoleResultMap">
        SELECT
            NAME AS role_name,
            role.create_time AS role_create_time,
            role.`describe` AS role_describe,
            STATUS AS role_status
        FROM
            role
    </select>

</mapper>

dao包：RoleDao:

package com.example.test4_23_2.dao;
import com.example.test4_23_2.entity.Role;
import org.apache.ibatis.annotations.Mapper;

import java.util.List;

@Mapper
public interface RoleDao {
    public Role selectPrivByRoleName(String rolename);
   List<Role>  selectAllRole();
}

service包
RoleService:

package com.example.test4_23_2.service;

import com.example.test4_23_2.entity.Role;

import java.util.List;

public interface RoleService {
    public Role selectPrivByRoleName(String rolename);
    List<Role> selectAllRole();
}

service.impl:
roleserviceimpl:

package com.example.test4_23_2.service.impl;


import com.example.test4_23_2.dao.RoleDao;
import com.example.test4_23_2.entity.Role;
import com.example.test4_23_2.service.RoleService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class RoleServiceimpl implements RoleService {
    @Autowired
    RoleDao roleDao;

    @Override
    public Role selectPrivByRoleName(String rolename) {
        return roleDao.selectPrivByRoleName(rolename);
    }

    @Override
    public List<Role> selectAllRole() {
        return roleDao.selectAllRole();
    }
}

controller:
RoleController:

package com.example.test4_23_2.controller;

import com.example.test4_23_2.common.Result;
import com.example.test4_23_2.entity.Role;
import com.example.test4_23_2.entity.User;
import com.example.test4_23_2.service.RoleService;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;


@Api(value = "角色管理")
@RestController
@RequestMapping("/role")
public class RoleController {
    @Autowired
    RoleService roleService;

    @ApiOperation(value = "通过角色名查找该角色名下的权限")
    @RequestMapping(value = "/findPrivByRoleName",method = RequestMethod.GET)
    public Result findPrivByRoleName(String rolename){
        Result result;
        try {
            Role role=roleService.selectPrivByRoleName(rolename);
            result=new Result(200,"成功",role);
        }catch (Exception ex){
            ex.printStackTrace();
            result=new Result(500,"错误");
        }
        return result;
    }

    @ApiOperation(value = "查找所有角色",httpMethod = "GET")
    @RequestMapping(value = "/selectAllRole",method = RequestMethod.GET)
    public  Result selectAllRole(){
        Result result;
        try {
            List<Role> list= roleService.selectAllRole();
            result=new Result(200,"成功",list);
        }catch (Exception e){
            e.printStackTrace();
            result=new Result(500,"失败");
        }
        return result;
    }

}

嗯，就没了吧大概
总之我可以运行。