一、统一返回数据格式

项目中我们会将响应封装成json返回，一般我们会将所有接口的数据格式统一， 使前端(iOS Android, Web)对数据的操作更一致、轻松。

一般情况下，统一返回数据格式没有固定的格式，只要能描述清楚返回的数据状态以及要返回的具体数据就可以。但是一般会包含状态码、返回消息、数据这几部分内容

例如，我们的系统要求返回的基本数据格式如下：

列表：

{
  "success": true,
  "code": 20000,
  "message": "成功",
  "data": {
    "items": [
      {
        "id": "1",
        "name": "刘德华",
        "intro": "毕业于师范大学数学系，热爱教育事业，执教数学思维6年有余"
      }
    ]
  }
}

分页：

{
  "success": true,
  "code": 20000,
  "message": "成功",
  "data": {
    "total": 17,
    "rows": [
      {
        "id": "1",
        "name": "刘德华",
        "intro": "毕业于师范大学数学系，热爱教育事业，执教数学思维6年有余"
      }
    ]
  }
}

没有返回数据：

{
  "success": true,
  "code": 20000,
  "message": "成功",
  "data": {}
}

失败：

{
  "success": false,
  "code": 20001,
  "message": "失败",
  "data": {}
}

因此，我们定义统一结果

{
  "success": 布尔, //响应是否成功
  "code": 数字, //响应码
  "message": 字符串, //返回消息
  "data": HashMap //返回数据，放在键值对中
}

二、创建模块guli-framework-common

1、创建模块

创建一个普通maven模块

Parent：guli-framework-parent

Artifact：guli-framework-common

2、配置 pom.xml

<dependencies>

    <!--swagger-->
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger2</artifactId>
    </dependency>
    <dependency>
        <groupId>io.springfox</groupId>
        <artifactId>springfox-swagger-ui</artifactId>
    </dependency>

    <!--lombok用来简化实体类：需要安装lombok插件-->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>

</dependencies>

3、创建返回码定义枚举类

创建包com.guli.common.constants，创建枚举类 ResultCodeEnum.java

package com.guli.common.constants;
import lombok.Getter;

@Getter
public enum ResultCodeEnum {

    SUCCESS(true, 20000,"成功"),
    UNKNOWN_REASON(false, 20001, "未知错误");

    private Boolean success;

    private Integer code;

    private String message;

    private ResultCodeEnum(Boolean success, Integer code, String message) {
        this.success = success;
        this.code = code;
        this.message = message;
    }
}

4、创建结果类

创建包com.guli.common.vo，创建类 R.java

vo：View Object

package com.guli.common.vo;

@Data
@ApiModel(value = "全局统一返回结果")
public class R {

    @ApiModelProperty(value = "是否成功")
    private Boolean success;

    @ApiModelProperty(value = "返回码")
    private Integer code;

    @ApiModelProperty(value = "返回消息")
    private String message;

    @ApiModelProperty(value = "返回数据")
    private Map<String, Object> data = new HashMap<String, Object>();

    private R(){}

    public static R ok(){
        R r = new R();
        r.setSuccess(ResultCodeEnum.SUCCESS.getSuccess());
        r.setCode(ResultCodeEnum.SUCCESS.getCode());
        r.setMessage(ResultCodeEnum.SUCCESS.getMessage());
        return r;
    }

    public static R error(){
        R r = new R();
        r.setSuccess(ResultCodeEnum.UNKNOWN_REASON.getSuccess());
        r.setCode(ResultCodeEnum.UNKNOWN_REASON.getCode());
        r.setMessage(ResultCodeEnum.UNKNOWN_REASON.getMessage());
        return r;
    }

    public static R setResult(ResultCodeEnum resultCodeEnum){
        R r = new R();
        r.setSuccess(resultCodeEnum.getSuccess());
        r.setCode(resultCodeEnum.getCode());
        r.setMessage(resultCodeEnum.getMessage());
        return r;
    }

    public R success(Boolean success){
        this.setSuccess(success);
        return this;
    }

    public R message(String message){
        this.setMessage(message);
        return this;
    }

    public R code(Integer code){
        this.setCode(code);
        return this;
    }

    public R data(String key, Object value){
        this.data.put(key, value);
        return this;
    }

    public R data(Map<String, Object> map){
        this.setData(map);
        return this;
    }
}

二、统一返回结果

1、guli-microservice-edu中添加依赖

添加对 guli-framework-common的依赖

guli-framework-parent中锁定版本

<dependencyManagement>
    <dependencies>

        <dependency>
            <groupId>com.guli</groupId>
            <artifactId>guli-framework-common</artifactId>
            <version>${guli.version}</version>
        </dependency>
        
    </dependencies>
</dependencyManagement>

guli-microservice-edu中添加依赖

<dependency>
    <groupId>com.guli</groupId>
    <artifactId>guli-framework-common</artifactId>
</dependency>

2、修改Controller中的返回结果

列表

@ApiOperation(value = "所有讲师列表")
@GetMapping
public R list(){
    List<Teacher> list = teacherService.list(null);
    return R.ok().data("items", list);
}

删除

@ApiOperation(value = "根据ID删除讲师")
@DeleteMapping("{id}")
public R removeById(
    @ApiParam(name = "id", value = "讲师ID", required = true)
    @PathVariable String id){
    teacherService.removeById(id);
    return R.ok();
}