如何全局捕获错误,记录它们并在J2EE应用程序中向用户显示错误页面

Question

我在google上搜索了这个主题并看到了一些最佳实践.但我需要一些具体的建议.我正在开发一个J2EE应用程序,它有来自JSP的servlets/Struts2 /对DAO的调用.所以应用程序是各种搞砸了.大多数数据是通过存储过程获取的,这些存储过程由iBatis ORM/Spring调用.有时当SP端发生错误时,它会向用户显示一条丑陋的消息,如下所示:

javax.servlet.ServletException: org.springframework.jdbc.BadSqlGrammarException: SqlMapClient operation; bad SQL grammar []; nested exception is com.ibatis.common.jdbc.exception.NestedSQLException:   
--- The error occurred in debtowed.xml.  
--- The error occurred while applying a parameter map.  
--- Check the debtowed.getFormerTenantData.  
--- Check the statement (update procedure failed).  
--- Cause: java.sql.SQLException: ORA-06550: line 1, column 11:
PLS-00905: object package.GET_FORMER_ADDRESS is invalid
ORA-06550: line 1, column 7:
PL/SQL: Statement ignored

Caused by: java.sql.SQLException: ORA-06550: line 1, column 11:
PLS-00905: object package.GET_FORMER_ADDRESS is invalid
ORA-06550: line 1, column 7:
PL/SQL: Statement ignored

此时,上述信息显示在浏览器中并记录到server.log.
但是,我想做以下事情:

• 显示自定义错误页面的用户
• 记录myapp.log中的错误而不是server.log(我们在其他地方使用log4j时这样做)

请告诉我这样做的最佳方式是什么？我应该在web.xml中添加一些东西吗？喜欢听众？这将是唯一的变化还是我必须更改现有代码？

代码不进行任何错误检查.它只是调用SP如下

getSqlMapClientTemplate().queryForList("sp.getfmrAddy", paramMap);

Answer 1

我希望Struts已经以某种方式解决了这个问题 - 所以最好检查struts docco.如果我是你,我会编写一个可以包装你的servlet调用的ExceptionFilter:

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Logger;

public class ExceptionFilter implements Filter{

private static final Logger logger = Logger.getLogger(ExceptionFilter.class);
private ExceptionService exceptionService = null;
@Override
public void destroy() {
    exceptionService.shutdown();
}

@Override
public void doFilter(ServletRequest rq, ServletResponse rs, FilterChain chain) throws IOException, ServletException {
    try {
        chain.doFilter(rq, rs); // this calls the servlet which is where your exceptions will bubble up from
    } catch (Throwable t) {
        // deal with exception, then do redirect to custom jsp page
        logger.warn(t);
        exceptionService.dealWithException(t); // you could have a service to track counts of exceptions / log them to DB etc
        HttpServletResponse response = (HttpServletResponse) resp;
        response.sendRedirect("somejsp.jsp");
    }
}

@Override
public void init(FilterConfig arg0) throws ServletException {
    // TODO Auto-generated method stub
    exceptionService = new ExceptionService();
}

}

并将其添加到您的web.xml:

<filter>
  <filter-name>ExceptionFilter</filter-name>
  <filter-class>com.example.ExceptionFilter</filter-class>
</filter>

<filter-mapping>
  <filter-name>ExceptionFilter</filter-name>
  <servlet-name>MyMainServlet</servlet-name>
</filter-mapping>

然后为所有servlet添加过滤器映射.

希望有所帮助.