Spring如何定义一个统一返回类呢?

定义统一返回类的实现思路:
    1.定义一个泛型类 用于返回类对象
	2.使用ResponseUtil封装 返回类
    3.使用@RestControllerAdvice拦截返回内容

统一返回类

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.annotation.JSONField;
import com.fasterxml.jackson.annotation.JsonProperty;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
 
@ApiModel(value = "response", description = "响应")
public class Response<T> {
    @JsonProperty("rsp_code")
    @JSONField(name = "rsp_code")
    @ApiModelProperty(value = "响应码(0:成功)", position = 1)
    private int rspCode = 0;
 
    @JsonProperty("rsp_desc")
    @JSONField(name = "rsp_desc")
    @ApiModelProperty(value = "响应码描述 ", position = 2)
    private String rspDesc = "successful";
 
    @ApiModelProperty(value = "数据", position = 5)
    private T data;
 
    public int getRspCode() {
        return rspCode;
    }
 
    public void setRspCode(int rspCode) {
        this.rspCode = rspCode;
    }
 
    public String getRspDesc() {
        return rspDesc;
    }
 
    public void setRspDesc(String rspDesc) {
        this.rspDesc = rspDesc;
    }
 
    public T getData() {
        return data;
    }
 
    public void setData(T data) {
        this.data = data;
    }
 
    @Override
    public String toString() {
        return JSON.toJSONString(this);
    }
}

import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
 
@ApiModel(value = "pagingResponse", description = "分页响应")
public class PagingResponse<T> extends Response<T> {
    @ApiModelProperty(value = "总条数", position = 3)
    private long total;
 
    @ApiModelProperty(value = "总页数", position = 4)
    private int pages;
 
    public long getTotal() {
        return total;
    }
 
    public void setTotal(long total) {
        this.total = total;
    }
 
    public int getPages() {
        return pages;
    }
 
    public void setPages(int pages) {
        this.pages = pages;
    }
}

统一返回工具类

import com.github.pagehelper.PageInfo;
import com.java265.common.DataEntity.Model.Response.Common.PagingResponse;
import com.java265.common.DataEntity.Model.Response.Common.Response;
import org.springframework.data.domain.Page;
 
import java.util.list;
 
public class ResponseUtil {
  
   public static <T> Response<T> out(T t) {
        Response<T> res = new Response<>();
        res.setData(t);
        return res;
    }
 
    public static <T> Response<T> outSuccess() {
        Response<T> res = new Response<>();
 
 
        return res;
    }
 
    public static <T> Response<T> outFail() {
        Response<T> res = new Response<>();
        res.setRspCode(-1);
        res.setRspDesc("操作失败");
 
        return res;
    }
 
 
    public static <T> PagingResponse<T> outNull() {
        PagingResponse<T> res = new PagingResponse<>();
        res.setData(null);
 
        return res;
    }
 
    public static <T> Response<T> outError(String desc) {
        Response<T> res = new Response<>();
        res.setRspCode(-1);
        res.setRspDesc(desc);
        return res;
    }
 
 
    public static <T> PagingResponse<List<T>> out(List<T> t, long total, int pages) {
        PagingResponse<List<T>> res = new PagingResponse<>();
        res.setData(t);
        res.setPages(pages);
        res.setTotal(total);
 
        return res;
    }
 
    public static <T> PagingResponse<List<T>> out(Page<T> page) {
 
        PagingResponse<List<T>> res = new PagingResponse<>();
        if (page == null) {
            return res;
        }
        res.setData(page.getContent());
        res.setPages(page.getTotalPages());
        res.setTotal(page.getTotalElements());
 
        return res;
    }
 
    public static <T> PagingResponse<List<T>> out(PageInfo<T> page) {
 
        PagingResponse<List<T>> res = new PagingResponse<>();
        if (page == null) {
            return res;
        }
        res.setData(page.getList());
        res.setPages(page.getPages());
        res.setTotal(page.getTotal());
 
        return res;
    }
 
    public static <T> PagingResponse<List<T>> outPageError(String desc) {
        PagingResponse<List<T>> res = new PagingResponse<>();
        res.setRspCode(-1);
        res.setRspDesc(desc);
        return res;
    }
}

controller二次封装

import com.github.pagehelper.PageInfo;
import com.java265.common.DataEntity.Model.Response.Common.Response;
import com.java265.core.DataApi.Common.Util.ResponseUtil;
import org.springframework.core.MethodParameter;
import org.springframework.data.domain.Page;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
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;
 
@RestControllerAdvice
public class ResponseHandler implements ResponseBodyAdvice<Object> {
 
    /**
     * 只处理有RestResponse注解的方法，防止处理其他不需要封装的，或者swaggwer等
     *
     * @param returnType
     * @param converterType
     * @return
     */
    @Override
    public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
        //直接返回true就是拦截所有的controller,也会拦截swagger的controller导致swagger不可用
        return returnType.hasMethodAnnotation(RestResponse.class);
    }
 
    @Override
    public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType,
                                  Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest request,
                                  ServerHttpResponse response) {
        Response respVo = null;
        if (body instanceof Response) {
            respVo = (Response) body;
        } else if (body instanceof Page) {
            Page page = (Page) body;
            respVo = ResponseUtil.out(page);
        } else if (body instanceof PageInfo) {
            PageInfo pageInfo = (PageInfo) body;
            respVo = ResponseUtil.out(pageInfo);
        } else {
            respVo = ResponseUtil.out(body);
        }
 
        //如果返回的字符串类型，会先判断HttpMessageConverter能否支持对应的返回类型再使用ResponseBodyAdvice进行封装
        //那么此时在进来就不是String类型，所以会报无法转换成ResponseVO对象,那么这里有两种方法，一种是直接返回json字符串，另一种是
        //一种是自己的WebConfig进行额外的配置
//		if (body instanceof String){
//			return JSONUtil.toJsonStr(respVo);
//		}
        return respVo;
    }
}

package com.java265.core.DataApi.Common.Response;
 
import java.lang.annotation.*;
 
/**
 * 
 * @Desc 忽略统一返回封装的注解
 * @date 2023/2/17 14:45
 */
@Documented
@Inherited
@Target({ElementType.ANNOTATION_TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.Runtime)
public @interface RestResponse {
 
}