SpringBoot全局处理统一返回类型方式

{
	"code": 200,   //响应状态
	"cost": 0,     //请求耗时，在本文章不做演示
	"data": "test",//返回数据
	"msg": "成功"   //响应描述
}

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.9</version>
        </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>
    </dependencies>

package com.gml.springboot2.entity;
import com.gml.springboot2.enums.ResultEnum;
import lombok.Data;
import java.io.Serializable;
/**
 * @author gml
 * @description  全局统一返回类型
 * @date 2019/11/29
 */
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Result<T> implements Serializable {
    /**
     * 成功数据
     */
    private T data;
    /**
     * 响应编码200为成功
     */
    private Integer code;
    /**
     * 请求消耗时间
     */
    private long cost;
    /**
     * 描述
     */
    private String msg;
    /**
     * 请求id
     */
    private String requestId;
    public Result(Integer code, String msg) {
        this.code = code;
        this.msg = msg;
    }
    public static Result create(Integer code, String msg){
        Result result = new Result(code, msg);
        return result;
    }
    /**
     * 无数据返回成功
     * @return
     */
    public static Result createSuccess() {
        return create(ResultEnum.SUCCESS.getCode(), ResultEnum.SUCCESS.getMsg());
    }
    /**
     * 有数据返回成功
     * @param data
     * @param <T>
     * @return
     */
    public static <T> Result<T> createSuccess(T data) {
        return createSuccess().setData(data);
    }
    /**
     * 无描述返回失败
     * @return
     */
    public static Result createFail() {
        return create(ResultEnum.Fail.getCode(), ResultEnum.Fail.getMsg());
    }
    /**
     * 自定义返回失败描述
     * @param code
     * @param msg
     * @return
     */
    public static Result createFail(Integer code, String msg) {
        return create(code, msg);
    }
    public Result setData(T data){
        this.data = data;
        return this;
    }
}

package com.gml.springboot2.config;
import com.alibaba.fastjson.JSONObject;
import com.gml.springboot2.entity.Result;
import org.springframework.core.MethodParameter;
import org.springframework.http.MediaType;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;
import java.util.Objects;
/**
 * @author gml
 * @description
 * @date 2019/11/29
 */
@RestControllerAdvice
public class CommonResponseAdvice implements ResponseBodyAdvice {
    @Override
    public boolean supports(MethodParameter methodParameter, Class aClass) {
        return filter(methodParameter);
    }
    /**
     * 根据返回类型来判断是否需要进行后续操作
     * @param methodParameter
     * @return
     */
    private boolean filter(MethodParameter methodParameter) {
        return true;
    }
    /**
     *
     * @param returnValue           返回值
     * @param methodParameter       Controller方法返回类型
     * @param mediaType
     * @param aClass
     * @param serverHttpRequest
     * @param serverHttpResponse
     * @return
     */
    @Override
    public Object beforeBodyWrite(Object returnValue, MethodParameter returnType, MediaType selectedContentType, Class selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {
        Result result;
        //获取返回值类型
        String returnClassType = returnType.getParameterType().getSimpleName();
        //如果返回值类型为void，则默认返回成功
        if("void".equals(returnClassType)){
            result = Result.createSuccess();
        }else if ("Result".equals(returnClassType)){
            result = (Result) returnValue;
        }else if ("String".equals(returnClassType)){
            //json的转换会出问题
            result = Result.createSuccess(returnValue);
            result.setCost(cost);
            return JSON.toJSONString(result);
        }else {
            if (Objects.isNull(returnValue)){
                result = Result.createSuccess();
            }else {
                result = Result.createSuccess(returnValue);
            }
        }
        //一定要转换为String，否则会报错
        return result;
    }
}

package com.gml.springboot2.controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
/**
 * @author gml
 * @description
 * @date 2019/11/29
 */
@RestController
public class TestController {
    @RequestMapping("/test")
    public String test(){
        return "返回数据";
    }
}