spring MVC 统一异常处理（webapi和web分开处理）

转载： http://blog.csdn.net/m13321169565/article/details/7641978

http://blog.csdn.net/ethan_fu/article/details/44624171

在使用web开发和API 开发都使用到异常的处理，web 异常后跳到指定的错误页面，那么API或AJAX调用需要返回JSON的错误信息，所以我们需要一个统一的异常处理机制来管理这些异常！

1.定义自己的异常处理类

import java.io.IOException;
import java.lang.reflect.Method;
import java.util.Collections;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.server.ServletServerHttpRequest;
import org.springframework.http.server.ServletServerHttpResponse;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver;

/**
 * 不必在Controller中对异常进行处理，抛出即可，由此异常解析器统一控制。<br>
 * ajax请求（有@ResponseBody的Controller）发生错误，输出JSON。<br>
 * 页面请求（无@ResponseBody的Controller）发生错误，输出错误页面。<br>
 * 需要与AnnotationMethodHandlerAdapter使用同一个messageConverters<br>
 * Controller中需要有专门处理异常的方法。
 *
 * @author dongjian
 *
 * */
public class AnnotationHandlerMethodExceptionResolver extends ExceptionHandlerExceptionResolver {

    private String defaultErrorView;

    public String getDefaultErrorView() {
        return defaultErrorView;
    }

    public void setDefaultErrorView(String defaultErrorView) {
        this.defaultErrorView = defaultErrorView;
    }

    /***
     * 异常后跳转到页面
     */
    protected ModelAndView doResolveHandlerMethodException(HttpServletRequest request, HttpServletResponse response, HandlerMethod handlerMethod, Exception exception) {

        if (handlerMethod == null) {
            return null;
        }

        Method method = handlerMethod.getMethod();

        if (method == null) {
            return null;
        }

        ModelAndView returnValue = super.doResolveHandlerMethodException(request, response, handlerMethod, exception);

        ResponseBody responseBodyAnn = AnnotationUtils.findAnnotation(method, ResponseBody.class);
        if (responseBodyAnn != null) {
            try {
                ResponseStatus responseStatusAnn = AnnotationUtils.findAnnotation(method, ResponseStatus.class);
                if (responseStatusAnn != null) {
                    HttpStatus responseStatus = responseStatusAnn.value();
                    String reason = responseStatusAnn.reason();
                    if (!StringUtils.hasText(reason)) {
                        response.setStatus(responseStatus.value());
                    } else {
                        try {
                            response.sendError(responseStatus.value(), reason);
                        } catch (IOException e) { }
                    }
                }

                return handleResponseBody(returnValue, request, response);
            } catch (Exception e) {
                return null;
            }
        }

        if(returnValue.getViewName() == null){
            returnValue.setViewName(defaultErrorView);
        }

        return returnValue;

    }


    /**
     * 异常后 返回json
     * @param returnValue
     * @param request
     * @param response
     * @return
     * @throws ServletException
     * @throws IOException
     */
    @SuppressWarnings({ "unchecked", "rawtypes" })
    private ModelAndView handleResponseBody(ModelAndView returnValue, HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        Map value = returnValue.getModelMap();
        HttpInputMessage inputMessage = new ServletServerHttpRequest(request);
        List<MediaType> acceptedMediaTypes = inputMessage.getHeaders().getAccept();
        if (acceptedMediaTypes.isEmpty()) {
            acceptedMediaTypes = Collections.singletonList(MediaType.ALL);
        }
        MediaType.sortByQualityValue(acceptedMediaTypes);
        HttpOutputMessage outputMessage = new ServletServerHttpResponse(response);
        Class<?> returnValueType = value.getClass();
        List<HttpMessageConverter<?>> messageConverters = super.getMessageConverters();
        if (messageConverters != null) {
            for (MediaType acceptedMediaType : acceptedMediaTypes) {
                for (HttpMessageConverter messageConverter : messageConverters) {
                    if (messageConverter.canWrite(returnValueType, acceptedMediaType)) {
                        messageConverter.write(value, acceptedMediaType, outputMessage);
                        return new ModelAndView();
                    }
                }
            }
        }
        if (logger.isWarnEnabled()) {
            logger.warn("Could not find HttpMessageConverter that supports return type [" + returnValueType + "] and " + acceptedMediaTypes);
        }
        return null;
    }

}

 2.在spring MVC 配置中添加如下配置

 

    <!--  ResponseBody 的类型 -->
<bean
    id="messageConverters" class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
         <property name="supportedMediaTypes">
             <list>
                 <value>application/json;charset=UTF-8</value>
             </list>
         </property>
 </bean>


<bean id="handlerAdapter"
    class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
    <property name="cacheSeconds" value="0" />
    <property name="messageConverters" ref="messageConverters" />
</bean>

<!-- 设置自定义异常处理 -->
   <bean id="handlerExceptionResolver" class="com.chengkun.base.exception.AnnotationHandlerMethodExceptionResolver">
    <property name="defaultErrorView" value="error.jsp"/><!-- 错误页面 -->
    <property name="messageConverters" ref="messageConverters"/> <!--JSON 处理的messageConverters->
</bean>

 3.修改web.xml 禁止自动注册，让其使用我们自定义的类

<servlet>
        <servlet-name>spring-mvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring/spring-mvc.xml</param-value>
        </init-param>

        <!-- 取消其自动注册的异常解析器 -->
        <init-param>
            <param-name>detectAllHandlerExceptionResolvers</param-name>
            <param-value>false</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

 4.在BaseController 中加入异常控制，所有controller必须继承BaseController

/**
    * 异常控制，可以根据不同的异常类型 在此定义不同的错误消息和操作
    * */
    @ExceptionHandler(Exception.class)
    @ResponseStatus(value=HttpStatus.INTERNAL_SERVER_ERROR)
    public ModelAndView handleException(Exception ex, HttpServletRequest request) {
        return new ModelAndView().addObject(new ResultPojo(500));
    }