浅谈rest風格的接口开发

简单描述：因为前后端分离，开发完模块之后，接到team leader的指令，我这个渣渣javaer需要给前端人员返回一个接口，具体内容是课程列表json和分类列表json。emmmm，第一次写接口，心理是有点啪啪啪的，手误，怕怕的，完全不知道应该怎么写。不过，程序员从来都不会说做不到，能做到的是想方设法的去搞定他。最终，还是把它搞出来了，哈哈哈哈，experience有增长了一点点。

过程：

创建实体类，并且使用@Table和数据库表相对应，@Getter@Setter都是lombok包下的 @Id@Table@Column是javax.persistence包下的

//实体类Course @Column中的是表字段 要注意的是必须和表完全对应，表里有多少字段，类就有多少属性 
@Getter
@Setter
@Table(name = "table_course")
public class Course {
    @Id
    @Column(name = "course_id")
    private String courseId;
    @Column(name = "course_name")
    private String courseName;
    @Column(name = "course_code")
    private String courseCode;
    @Column(name = "course_type")
    private String courseType;
    @Column(name = "is_del")
    private String isDel;//未删除 1 已删除 0
} 

//实体类Dictionary
import lombok.Getter;
import lombok.Setter;

import javax.persistence.Column;
import javax.persistence.Id;
import javax.persistence.Table;

@Getter
@Setter
@Table(name = "table_dict")
public class Dictionary {
    @Id
    @Column(name = "dict_id")
    private String dictId;
    @Column(name = "dict_name")
    private String dictName;
    @Column(name = "dict_code")
    private String dictCode;
    @Column(name = "sort_no")
    private String sortNo;
    @Column(name = "parent_id")
    private String parentId;
    @Column(name = "description")
    private String description;
} 

Controller层

//controller层 
import xxx.xx.xxxxx.xxxx.xxxxx.ResultDto;
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;
import java.util.Map;
@Api(value = "CourseController",tags = "课程相关查询")
@RestController
@RequestMapping("/course")
public class CourseController extends BaseController {
    @Autowired
    private CourseService courseService;

    @ApiOperation(value = "获取课程列表" notes= "获取课程列表")
    @RequestMapping(value = "/queryList", method = RequestMethod.GET, produces = "application/json;charset=utf-8")
    public ResultDto queryList(){
        List<CourseVo> list = null;
        try {
            list = courseService.queryList();
            if(list != null){
                if(list.size()<1){
                    return ResultDto.success("返回结果无内容");
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
            return ResultDto.error();
        }
        return ResultDto.success(list);
    }

    @ApiOperation(value = "获取课程分类列表",notes = "根据课程编码查询")
    @RequestMapping(value = "/getCourseType",method = RequestMethod.GET, produces = "application/json;charset=utf-8")
    public ResultDto getCourseType(String code){
        List<Map<String,String>> list = null;
        try {
            if (!"".equals(code) && code != null) {
                list = courseService.getCourseType(code);
                if(list != null){
                    if(list.size()<1){
                        return ResultDto.success("返回结果无内容");
                    }
                }
            }else{
                return ResultDto.error("参数错误");
            }
        } catch (Exception e) {
            e.printStackTrace();
            return ResultDto.error();
        }
        return  ResultDto.success(list);
    }
} 

Service层

//service层
import org.springframework.beans.BeanUtils;
import org.springframework.stereotype.Service;
import tk.mybatis.mapper.entity.Example;

import javax.annotation.Resource;

@Service
public class CourseService {
    @Resource
    private CourseMapper courseMapper;
    @Resource
    private DictionaryMapper dictionaryMapper;

    public List<CourseVo> queryList()throws Exception{
        Example example = new Example(Course.class);
        example.createCriteria().andEqualTo("isDel",1);
        List<Course> list = courseMapper.selectByExample(example);
        List<CourseVo> reList = new ArrayList<>();
        if (list !=null){
            for(Course obj:list){
                CourseVo course = new CourseVo();
                BeanUtils.copyProperties(obj,course);
                reList.add(course);
            }
        }
        return reList;
    }

    public List<Map<String,String>> getCourseType(String code) throws Exception{
        Dictionary obj = new Dictionary();
        obj.setDictCode(code);
        Dictionary dict = dictionaryMapper.selectOne(obj);
        Example example = new Example(Dictionary.class);
        example.createCriteria().andEqualTo("parentId",dict.getDictId());
        List<Dictionary> list = DictionaryMapper.selectByExample(example);
        List<Map<String,String>> reList = new ArrayList<>();
        if(list != null){
            for(Dictionary test:list){
                Map<String,String> map = new HashMap<>();
                map.put(test.getDictName(),test.getDictCode());
                reList.add(map);
            }
        }
        return reList;
    }
} 

对应的Mapper接口

//CourseMapper接口
import xxx.xx.xxxxxx.xxxx.util.MyMapper;

public interface CourseMapper extends MyMapper<Course> {
} 

//DictionaryMapper接口
import xxx.xx.xxxxxx.xxxx.util.MyMapper;

public interface DictionaryMapper extends MyMapper<Dictionary>{
}

MyMapper<T>

//MyMapper接口
/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2014-2016 abel533@gmail.com
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package xxx.xx.xxxxxx.xxxxx.util;

import tk.mybatis.mapper.common.Mapper;
import tk.mybatis.mapper.common.MySqlMapper;

/**
 * 继承自己的 MyMapper
 */
public interface MyMapper<T> extends Mapper<T>, MySqlMapper<T> {
    //TODO
    //FIXME 特别注意，该接口不能被扫描到，否则会出错
} 

注意：可以使用google浏览器的postman插件  或者 火狐浏览器的RestClient插件来进行接口的测试工作。输入地址的时候要确保和配置文件里的端口号对应。

总结：第一次开发接口，能顺利的搞出来真的是挺开心的，以前的时候就在好奇，经常听接口开发之类的，也会有疑问 如果自己来开发接口的话能不能开发出来。

相关注解详细参考：https://blog.csdn.net/xiaojin21cen/article/details/78654652