今天在整理之前的项目的时候想着有的action层没有做异常处理，于是想着自定义拦截器处理一下未拦截的异常。
代码:
package cn.xm.exam.action.safeHat;import java.util.HashMap;
import java.util.Map;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Controller;import com.opensymphony.xwork2.ActionSupport;@Controller
@Scope("prototype")
public class SafeHatAction extends ActionSupport {
private static final Logger log = LoggerFactory.getLogger(SafeHatAction.class);
private Map<String, Object> response; public SafeHatAction() {
log.info("SafeHatAction init.........");
} public String test1() {
response = new HashMap();
response.put("ttt", "tttttt");
return SUCCESS;
} public String test2() {
response = new HashMap();
response.put("ttt", "tttttt");
int i = 1/0;
return SUCCESS;
} public Map<String, Object> getResponse() {
return response;
} public void setResponse(Map<String, Object> response) {
this.response = response;
}}
1.异常在Action层未做处理的情况:
由于在web.xml中定义了500错误的页面，因此跳转到500页面，如下:
<!-- 500页面 -->
<error-page>
<error-code>500</error-code>
<location>/500.jsp</location>
</error-page>
可是上面终究不够友好。
2.自定义拦截器处理全局异常
(1)自定义拦截器
package cn.xm.exam.interceptor;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.Interceptor;public class ExceptionInterception implements Interceptor {
private static final Logger log = LoggerFactory.getLogger(ExceptionInterception.class);
/**
*
*/
private static final long serialVersionUID = 2268867259828199826L; @Override
public void destroy() { } @Override
public void init() { } @Override
public String intercept(ActionInvocation arg0) throws Exception {
log.info("enter ExceptionInterception intercept ... ");
String result = "";
try {
result = arg0.invoke();
log.info("result -> {}", result);
} catch (Throwable e) {
log.error("未处理的异常在拦截器被拦截,class:{}", arg0.getAction().getClass(), e);
throw new Exception(e);
}
log.debug("exit ExceptionInterception intercept ... ");
return result;
}}
arg0.invoke();是调用我们的action的方法，其返回值就是action的返回值,相当于放行;捕捉到异常之后进行一个简单的异常记录之后再次抛出异常，再次抛出异常是为了跳到500页面;如果有需要可以自己再写一个页面提示错误已经被记录等信息，捕捉到异常之后返回到此页面。
(2)struts.xml中定义拦截器
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd"><struts>
<constant name="struts.i18n.encoding" value="utf-8"></constant>
<constant name="devMode" value="true"></constant>
<constant name="struts.enable.DynamicMethodInvocation" value="true" />
<!-- 配置拦截的后缀 -->
<constant name="struts.action.extension" value="action,do" />
<!-- 与spring整合 -->
<constant name="struts.objectFactory" value="spring"></constant> <package name="interceptPackage" extends="json-default"> <!-- 拦截器 -->
<interceptors>
<!-- 定义刚才的拦截器 -->
<interceptor name="exceptionInterceptor"
class="cn.xm.exam.interceptor.ExceptionInterception"></interceptor>
<!-- 定义拦截器栈 -->
<interceptor-stack name="myStack">
<!-- 拦截器栈里面可以引用另外一个拦截器，也可以引用另外一个拦截器栈 -->
<interceptor-ref name="defaultStack"></interceptor-ref>
<interceptor-ref name="exceptionInterceptor"></interceptor-ref>
</interceptor-stack>
</interceptors>
<!-- 这句是设置所有Action自动调用的拦截器堆栈 -->
<default-interceptor-ref name="myStack" />
</package> <!-- 2018-11-11引入的二开action -->
<include file="struts/safeHat.xml"></include></struts>
自定义的package继承上面的package(package具有多重继承的特性，safeHalt会继承其所有父类)，例如:safeHat.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd"><struts>
<package name="safeHalt" namespace="/" extends="interceptPackage">
<!-- 全局结果集，将response转换为json传到前台 -->
<global-results>
<result name="success" type="json">
<param name="root">response</param>
</result>
</global-results> <action name="safeHat_*" class="safeHatAction" method="{1}"></action>
</package>
</struts>
(3)继续访问上面的错误action进行测试:
查看记录的错误日志:
2018-11-01 23:09:30 [cn.xm.exam.interceptor.ExceptionInterception]-[ERROR] 未处理的异常在拦截器被拦截,class:class cn.xm.exam.action.safeHat.SafeHatAction
java.lang.ArithmeticException: / by zero
at cn.xm.exam.action.safeHat.SafeHatAction.test2(SafeHatAction.java:32)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:871)
at ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1294)
at ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68)
at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:117)
at com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:108)
at ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1370)
at ognl.ASTMethod.getValueBody(ASTMethod.java:91)
........
至此实现了简单的全局异常处理。
3.补充:根据ajax请求与普通请求回传不同数据 (捕捉到异常之后进行提示)
3.1首先明白ajax请求与普通请求的不同:
AJAX请求头会多一个x-requested-with参数，值为XMLHttpRequest
String requestType = request.getHeader("X-Requested-With");
3.2修改上面的拦截器
package cn.xm.exam.interceptor;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;import com.opensymphony.xwork2.ActionInvocation;
import com.opensymphony.xwork2.interceptor.Interceptor;public class ExceptionInterception implements Interceptor {
private static final Logger log = LoggerFactory.getLogger(ExceptionInterception.class);
/**
*
*/
private static final long serialVersionUID = 2268867259828199826L; @Override
public void destroy() { } @Override
public void init() { } @Override
public String intercept(ActionInvocation arg0) throws Exception {
log.info("enter ExceptionInterception intercept ... ");
String result = "";
try {
result = arg0.invoke();
log.info("result -> {}", result);
} catch (Throwable e) {
log.error("未处理的异常在拦截器被拦截,class:{}", arg0.getAction().getClass(), e);
return "interceptorError";
}
log.debug("exit ExceptionInterception intercept ... ");
return result;
}}
struts全局结果集:
<package name="interceptPackage" extends="json-default">
<!-- 拦截器 -->
<interceptors>
<!-- 定义刚才的拦截器 -->
<interceptor name="exceptionInterceptor"
class="cn.xm.exam.interceptor.ExceptionInterception"></interceptor>
<!-- 定义拦截器栈 -->
<interceptor-stack name="myStack">
<!-- 拦截器栈里面可以引用另外一个拦截器，也可以引用另外一个拦截器栈 -->
<interceptor-ref name="defaultStack"></interceptor-ref>
<interceptor-ref name="exceptionInterceptor"></interceptor-ref>
</interceptor-stack>
</interceptors>
<!-- 这句是设置所有Action自动调用的拦截器堆栈 -->
<default-interceptor-ref name="myStack" /> <!-- 拦截器拦截的全局异常 -->
<global-results>
<result name="interceptorError">/interceptorError.jsp</result>
</global-results>
</package>
错误JSP:interceptorError.jsp
<%@ page contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%
if (request.getHeader("X-Requested-With") != null
&& "XMLHttpRequest".equals(request.getHeader("X-Requested-With"))) {
response.setContentType("application/javascript;charset=utf-8");
out.write("错误提醒:系统发生错误,系统已经记录错误日志");
} else {
response.setContentType("text/html;charset=\"utf-8\"");
out.write(
"<html><head><meta charset=\"utf-8\" /><title>错误提醒</title></head><body><br /><span style=\"font-weight: bold;font-size: 20px;margin: 20px;\">系统发生错误!日志已经记录!</span> <br /></body></html>");
}
%>
测试:
(1)普通页面访问:
(2)ajax请求测试:
js代码:
<script>
+function(){
$.post("/Exam/safeHat_test2.do",function(response){
alert(response);
},"text");
}();
</script>
结果:
拦截器的使用参考我另一篇博客:https://www.cnblogs.com/qlqwjy/p/7190784.html
