Spring Boot 统一数据返回格式 分析 和 处理

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.ControllerAdvice;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;
 
@ControllerAdvice
public class GlobalResponseHandler implements ResponseBodyAdvice<Object> {
 
    @Override
    public boolean supports(MethodParameter returnType, Class converterType) {
        return true;
    }
 
    @Override
    public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType,
                                  Class selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {
        // 判断是否为跨域请求及构建统一返回格式
        if (RequestContextHolder.getRequestAttributes() != null) {
            ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
            String origin = attributes.getRequest().getHeader("Origin");
            if (origin != null) {
                response.getHeaders().set("Access-Control-Allow-Origin", origin);
                response.getHeaders().set("Access-Control-Allow-Credentials", "true");
            }
        }
 
        // 构建统一的返回格式
        Result result = new Result();
        if (body instanceof Result) {
            result = (Result) body;
        } else {
            result.setData(body);
        }
        return result;
    }
}
 
class Result<T> {
    private int code;
    private String message;
    private T data;
 
    // 省略getter和setter方法...
}

这个代码实例展示了如何在Spring Boot应用中使用@ControllerAdvice和ResponseBodyAdvice来实现全局的响应处理，统一输出格式。在beforeBodyWrite方法中，我们首先判断是否为跨域请求，并对响应头进行设置，然后构建统一的返回结果格式。这样，每个响应体都会被处理，并且添加了统一的格式，方便客户端处理。