spring mvc捕获异常时,如何判断应该返回json还是跳转错误页面
在异常捕获handler BusinessExceptionHandlerAdvice中
判断控制器的方法是否有ResponseBody注解,如果有,则返回json,
关键问题是:
如何判断控制器的方法是否有ResponseBody注解
我们先看看@ExceptionHandler方法中注入的参数有哪些?
1. ServletResponse.class 2. OutputStream.class 3. Writer.class 4. WebRequest.class 5. ServletRequest.class 6. MultipartRequest.class 7. HttpSession.class 8. Principal.class 9. Locale.class 10. InputStream.class 11. Reader.class
直接获取控制器方法(java.lang.reflect.Method)的计划破灭了,
那么还有没有其他方法呢?
有!通过异常的堆栈 StackTraceElement
那么StackTraceElement有哪些信息呢?
所以我们可以通过反射获取控制器方法,然后判断是否有注解ResponseBody.class
具体实现(直接上代码):
package oa.web.controller.handler;
import com.common.bean.BaseResponseDto;
import com.common.bean.exception.LogicBusinessException;
import com.common.util.ReflectHWUtils;
import com.common.util.SystemHWUtil;
import com.common.util.WebServletUtil;
import com.string.widget.util.ValueWidget;
import org.apache.log4j.Logger;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.lang.reflect.Method;
import java.net.URLEncoder;
/**
* Created by whuanghkl on 3/30/16.
* 注意使用注解@ControllerAdvice作用域是全局Controller范围
* 可应用到所有@RequestMapping类或方法上的@ExceptionHandler、@InitBinder、@ModelAttribute,在这里是@ExceptionHandler<br />
* 用于检测第三方接口,比如bsvc或cia的504,502等异常<br />
* 这些异常均属于非业务异常,与业务毫无关系,所以单独处理<br />
* 注意:StoreBusinessException 不要捕获,否则无法被BusinessExceptionHandlerAdvice 截获<br />
* 注意:传递url中的参数如果可能包含中文一定要URL编码,
*/
@ControllerAdvice
public class BusinessExceptionHandlerAdvice {
public static Logger logger = Logger.getLogger(BusinessExceptionHandlerAdvice.class);
/***
* 判断接口的注解是否是ResponseBody,是,那么返回json,而不是跳转错误页面
* @param stackTraceElement
* @return
*/
public static boolean isControllerAction(StackTraceElement stackTraceElement) {
String className = stackTraceElement.getClassName();
if (className.endsWith("Controller")) {
try {
Class controllerClass = Class.forName(className);
Method actionMethod = ReflectHWUtils.getMethod(controllerClass, stackTraceElement.getMethodName(), ResponseBody.class);
if (null == actionMethod) {
return false;
}
return true;
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
return false;
}
/***
* 判断接口的注解是否是ResponseBody,是,那么返回json,而不是跳转错误页面<br />
* 限制最多循环4次,否则影响性能
* @param stackTraceElements
* @return
*/
public static boolean isControllerAction(StackTraceElement[] stackTraceElements) {
int length = stackTraceElements.length;
if (length > 4) {
length = 4;
}
for (int i = 0; i < length; i++) {
StackTraceElement stackTraceElement = stackTraceElements[i];
if (isControllerAction(stackTraceElement)) {
return true;
}
}
return false;
}
@ExceptionHandler(LogicBusinessException.class)
// @RESPONSE_CONTENTTYPE_JSON_UTFStatus(HttpStatus.BAD_REQUEST)
// @ResponseBody
public String handleBusinessException(LogicBusinessException ex, HttpSession session, HttpServletRequest request, HttpServletResponse response) {
// return ClassUtils.getShortName(ex.getClass()) + ex.getMessage();
logger.error(ex);//{errorCode='1021', errorMessage='用户不在组织的企业客户身份中'}
logger.error("old url:" + request.getRequestURL());
logger.error("query string:" + request.getQueryString());
StackTraceElement[] stackTraceElements = ex.getStackTrace();
if (!ex.isWap()) {
boolean isControllerAction = isControllerAction(stackTraceElements);
System.out.println("isControllerAction :" + isControllerAction);
if (isControllerAction) {
ex.setWap(true);//表示返回json
}
}
if (ex.isWap() || WebServletUtil.getMobileOsInfo(request).isMobile()) {//如果是手机端
PrintWriter out = null;
try {
out = response.getWriter();
} catch (IOException e) {
e.printStackTrace();
}
if (ValueWidget.isNullOrEmpty(ex.getResponseBody())) {
out.print(new BaseResponseDto(ex.getErrorCode(), ex.getErrorMessage()).toJson());
} else {
out.print(ex.getResponseBody());
}
out.flush();
} else {
String redirectUrl = null;
if (ValueWidget.isNullOrEmpty(ex.getRedirectUrl())) {
String message = null;
message = getMessage(ex);
redirectUrl = "/error.html?error=" + ex.getErrorCode() + "&errorMessage=" + message;
} else {
redirectUrl = ex.getRedirectUrl();
}
logger.error("redirect url:" + redirectUrl);
try {
response.sendRedirect(redirectUrl);
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
/***
*
* @param ex
* @param message :中文已经经过url 编码
* @return
*/
private static String getMessage(LogicBusinessException ex) {
String message = null;
if (ValueWidget.isNullOrEmpty(ex.getErrorMessage())) {
message = SystemHWUtil.EMPTY;
} else {
try {
message = URLEncoder.encode(ex.getErrorMessage(), "UTF-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
return message;
}
}
简单说明下:
先判断isWap是否为true,如果为true,说明已经手动指定返回json了,那么就不用判断了.
否则才需要通过StackTraceElement判断