springBoot如何自定义异常响应

1 自定义异常返回json数据、

//不要忘记添加 @ControllerAdvice

@ControllerAdvice

public class myExceptionHandler {

//浏览器和客户端返回的都是json

// @ResponseBody

@ExceptionHandler(UserNotExist.class)

public Map<String ,Object> handlerException(Exception e){

   Map<String,Object> map = new HashMap<>();
   
   map.put("code","user.notexist");
   
   map.put("message",e.getMessage());
   
   return map;

} }

2 转发到/error下，进行自适应响应 @ControllerAdvice public class myExceptionHandler {

//浏览器和客户端返回的都是json

@ExceptionHandler(UserNotExist.class)

public String handlerException(Exception e, HttpServletRequest request){

    Map<String,Object> map = new HashMap<>();
	
    request.setAttribute("javax.servlet.error.status_code",500);
	
    map.put("code","user.notexist");
	
    map.put("message",e.getMessage());
	
    request.setAttribute("ext",map);
	
    return "forward:/error";
	
}

}

3 将定制的错误携带出去 @Component

public class myErrorAtrributes extends DefaultErrorAttributes {

//WebRequest webRequest,注意1.x.x版本的写法与2.1.0写法不一样，个人是2.1.0

public Map<String, Object> getErrorAttributes(WebRequest webRequest, boolean includeStackTrace) {

    Map<String, Object> errorAttributes = super.getErrorAttributes(webRequest,includeStackTrace);
	
    errorAttributes.put("com", "maodong");
	
    Map<String,Object> ext= (Map<String, Object>) webRequest.getAttribute("ext",0);
	
    errorAttributes.put("ext",ext);
	
    return errorAttributes;
	
}

}

//为啥这么写：父类DefaultErrorAttributes类中的方法

public Map<String, Object> getErrorAttributes(WebRequest webRequest, boolean includeStackTrace) {

Map<String, Object> errorAttributes = new LinkedHashMap();
	
    errorAttributes.put("timestamp", new Date());
	
    this.addStatus(errorAttributes, webRequest);
	
    this.addErrorDetails(errorAttributes, webRequest, includeStackTrace);
	
    this.addPath(errorAttributes, webRequest);
	
    return errorAttributes;
}

//为啥WebRequest webRequest能获得与低版本RequestAttrributes相同的结果

public interface WebRequest extends RequestAttributes {
@Nullable
String getHeader(String var1);

@Nullable
String[] getHeaderValues(String var1);

Iterator<String> getHeaderNames();
------
}

//为啥  Map<String,Object> ext= (Map<String, Object>) webRequest.getAttribute("ext",0);能得到ext

public interface RequestAttributes {
int SCOPE_REQUEST = 0;
int SCOPE_SESSION = 1;
String REFERENCE_REQUEST = "request";
String REFERENCE_SESSION = "session";

@Nullable
Object getAttribute(String var1, int var2);

void setAttribute(String var1, Object var2, int var3);

void removeAttribute(String var1, int var2);