应用场景:当浏览器向浏览器发送申请,而服务器解决申请呈现了异样的状况,如果间接把错误信息给浏览器展现进去是很不好的,因为用户就能看到具体的代码错误信息。所以当出现异常状况时,服务器能够给用户一个本次申请异样的页面,让用户晓得以后服务器有点问题,请稍后再试。
实现流程
- 1)自定义异样类
public class MyException extends RuntimeException{
private String message;
public MyException(){}
public MyException(String message){this.message = message;}
public void setMessage(String message) {this.message = message;}
@Override
public String getMessage() {return message;}
}
-
2)自定义异样解决类,解决咱们抛出的异样
- 对于异样的解决,我是把它转发到一个 error 页面,这里大家能够本人创立一个
@Component
public class ExceptionResolver implements HandlerExceptionResolver {
@Override
public ModelAndView resolveException(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) {if (e instanceof MyException){ModelAndView mv = new ModelAndView();
mv.addObject("errorMessage", e.getMessage());
mv.setViewName("error.jsp");
return mv;
}
return null;
}
}
- Controller 类:这里是捕捉了一个空指针异样,而后抛出了咱们自定义的异样
@Controller
public class UserController {@RequestMapping("testException.do")
public String testException(){
try {
String str = null;
str.length();}catch (NullPointerException e){e.printStackTrace();
throw new MyException("服务器忙碌,请稍后再试!!!");
}
return "testException.jsp";
}
}
- ApplicationContext.xml(Spring 外围配置文件)配置信息如下:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/aop https://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/mvc https://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!-- 开启 spring 注解驱动 -->
<context:component-scan base-package="com.cjh"/>
<!-- 开启 mvc 注解驱动 -->
<mvc:annotation-driven></mvc:annotation-driven>
</beans>