一、前言
项目刚刚开发的时候,并没有做好充足的准备。开发到一定程度的时候才会想到还有一些问题没有解决。就比如今天我要说的一个问题:异常的处理。写程序的时候一般都会通过try...catch...finally对异常进行处理,但是我们真的能在写程序的时候处理掉所有可能发生的异常吗? 以及发生异常的时候执行什么逻辑,返回什么提示信息,跳转到什么页面,这些都是要考虑到的。
二、基于@ControllerAdvice(加强的控制器)的异常处理
@ControllerAdvice注解内部使用@ExceptionHandler、@InitBinder、@ModelAttribute注解的方法应用到所有的 @RequestMapping注解的方法。本例子中使用ExceptionHandler应用到所有@RequestMapping注解的方法,处理发生的异常。
示例代码:
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import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.http.HttpHeaders; import org.springframework.http.HttpStatus; import org.springframework.http.ResponseEntity; import org.springframework.util.StringUtils; import org.springframework.web.bind.annotation.ControllerAdvice; import org.springframework.web.bind.annotation.ExceptionHandler; import org.springframework.web.bind.annotation.ResponseBody; import com.hjz.exception.ServiceException; import com.hjz.exception.utils.ExceptionUtils; @ResponseBody public class ExceptionAdvice { private static final Logger LOGGER = LoggerFactory.getLogger(ExceptionAdvice. class ); /** * 拦截web层异常,记录异常日志,并返回友好信息到前端 * 目前只拦截Exception,是否要拦截Error需再做考虑 * * @param e 异常对象 * @return 异常提示 */ @ExceptionHandler (Exception. class ) public ResponseEntity<String> handleException(Exception e) { //不需要再记录ServiceException,因为在service异常切面中已经记录过 if (!(e instanceof ServiceException)) { LOGGER.error(ExceptionUtils.getExcTrace(e)); } HttpHeaders headers = new HttpHeaders(); headers.set( "Content-type" , "text/plain;charset=UTF-8" ); headers.add( "icop-content-type" , "exception" ); String message = StringUtils.isEmpty(e.getMessage()) ? "系统异常!!" : e.getMessage(); return new ResponseEntity<>(message, headers, HttpStatus.OK); } } |
如果不起作用,请检查 spring-mvc的配置文件,是否有ControllerAdvice的如下配置
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< context:component-scan base-package = "com.sishuok.es" use-default-filters = "false" > < context:include-filter type = "annotation" expression = "org.springframework.stereotype.Controller" /> < context:include-filter type = "annotation" expression = "org.springframework.web.bind.annotation.ControllerAdvice" /> </ context:component-scan > |
三、基于AOP的异常处理
1.处理controller层的异常 WebExceptionAspect.java
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import org.aspectj.lang.annotation.AfterThrowing; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Pointcut; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.stereotype.Component; import org.springframework.util.StringUtils; import org.springframework.web.context.request.RequestContextHolder; import org.springframework.web.context.request.ServletRequestAttributes; import com.hjz.exception.ServiceException; import com.hjz.exception.utils.ExceptionUtils; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.io.PrintWriter; /** * web异常切面 * 默认spring aop不会拦截controller层,使用该类需要在spring公共配置文件中注入改bean, * 另外需要配置<aop:aspectj-autoproxy proxy-target-class="true"/> */ @Aspect public class WebExceptionAspect { private static final Logger LOGGER = LoggerFactory.getLogger(WebExceptionAspect. class ); @Pointcut ( "@annotation(org.springframework.web.bind.annotation.RequestMapping)" ) private void webPointcut() {} /** * 拦截web层异常,记录异常日志,并返回友好信息到前端 * 目前只拦截Exception,是否要拦截Error需再做考虑 * * @param e 异常对象 */ @AfterThrowing (pointcut = "webPointcut()" , throwing = "e" ) public void handleThrowing(Exception e) { //不需要再记录ServiceException,因为在service异常切面中已经记录过 if (!(e instanceof ServiceException)) { LOGGER.error(ExceptionUtils.getExcTrace(e)); } String errorMsg = StringUtils.isEmpty(e.getMessage()) ? "系统异常" : e.getMessage(); writeContent(errorMsg); } /** * 将内容输出到浏览器 * * @param content 输出内容 */ private void writeContent(String content) { HttpServletResponse response = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getResponse(); response.reset(); response.setCharacterEncoding( "UTF-8" ); response.setHeader( "Content-Type" , "text/plain;charset=UTF-8" ); response.setHeader( "icop-content-type" , "exception" ); PrintWriter writer = null ; try { writer = response.getWriter(); } catch (IOException e) { e.printStackTrace(); } writer.print(content); writer.flush(); writer.close(); } } |
2.处理service层的异常ServiceExceptionAspect .java
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import org.aspectj.lang.JoinPoint; import org.aspectj.lang.annotation.AfterThrowing; import org.aspectj.lang.annotation.Aspect; import org.aspectj.lang.annotation.Pointcut; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.stereotype.Component; import org.springframework.util.StringUtils; import com.hjz.exception.ServiceException; import com.hjz.exception.utils.ExceptionUtils; @Aspect public class ServiceExceptionAspect { private static final Logger LOGGER = LoggerFactory.getLogger(ServiceExceptionAspect. class ); /** * @within(org.springframework.stereotype.Service),拦截带有 @Service 注解的类的所有方法 * @annotation(org.springframework.web.bind.annotation.RequestMapping),拦截带有@RquestMapping的注解方法 */ @Pointcut ( "@within(org.springframework.stereotype.Service) && execution(public * *(..))" ) private void servicePointcut() {} /** * 拦截service层异常,记录异常日志,并设置对应的异常信息 * 目前只拦截Exception,是否要拦截Error需再做考虑 * * @param e 异常对象 */ @AfterThrowing (pointcut = "servicePointcut()" , throwing = "e" ) public void handle(JoinPoint point, Exception e) { LOGGER.error(ExceptionUtils.getExcTrace(e)); String signature = point.getSignature().toString(); String errorMsg = getMessage(signature) == null ? (StringUtils.isEmpty(e.getMessage()) ? "服务异常" : e.getMessage()) : getMessage(signature); throw new ServiceException(errorMsg, e); } /** * 获取方法签名对应的提示消息 * * @param signature 方法签名 * @return 提示消息 */ private String getMessage(String signature) { return null ; } } |
3.使用方式,在spring的公共配置文件中加入如下配置:
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< aop:aspectj-autoproxy proxy-target-class = "true" /> < bean class = "com.hjz.exception.aspect.ServiceExceptionAspect" /> < bean class = "com.hjz.exception.aspect.WebExceptionAspect" /> |
或者 自定义一个 注册类,ServiceExceptionAspect.java和WebExceptionAspect.java都加入@Component注解
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import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Configuration; import org.springframework.context.annotation.EnableAspectJAutoProxy; /** * 异常相关bean注册类 */ @Configuration @EnableAspectJAutoProxy @ComponentScan ( "com.hjz.exception.aspect" ) public class ExceptionConfig { } |
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@Aspect @Component public class WebExceptionAspect { .......... } @Aspect @Component public class ServiceExceptionAspect { ......... } |
四、疑惑
@within(org.springframework.stereotype.Service),拦截带有 @Service 注解的类的所有方法
@annotation(org.springframework.web.bind.annotation.RequestMapping),拦截带有@RquestMapping的注解方法
五、测试
分别编写controller层和service层的异常测试类。这个很简单,在方法里简单的抛一下异常就可以了。最后验证一下,异常发生的时候有没有 执行 @AfterThrowing对应的方法就好了。具体还是看我写的demo吧,嘿嘿嘿!!!
完整项目下载地址:Spring-AOP.rar
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。
原文链接:http://www.cnblogs.com/hujunzheng/p/6255463.html