会servlet的帮看下

[zkmhywgsym]

pro.findAll()是对数据库的查找
main方法能运行出想要的结果 service会报如下错误,求助,今天下午在线等,可加QQ:413219099

package service;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class Main extends HttpServlet {

protected void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {req.setCharacterEncoding("utf-8");
resp.setContentType("text/html");
ProductDaoImp pro=new ProductDaoImp();
System.out.println(pro.findAll());
}

public static void main(String[] args) {
ProductDaoImp pro=new ProductDaoImp();
System.out.println(pro.findAll());

}

}


2013-3-16 13:23:56 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet mainServlet threw exception
java.lang.NullPointerException
at service.ProductDaoImp.findAll(ProductDaoImp.java:50)
at service.Main.service(Main.java:18)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:619)

java.io.FileNotFoundException: src\service\pro.properties (系统找不到指定的路径。)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(FileInputStream.java:106)
at java.io.FileInputStream.<init>(FileInputStream.java:66)
at service.ReadPro.readPrapertiesByName(ReadPro.java:17)
at service.DBM.getConnect(DBM.java:11)
at service.ProductDaoImp.<init>(ProductDaoImp.java:10)
at service.Main.service(Main.java:17)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:619)

java.lang.ClassNotFoundException:
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:169)
at service.DBM.getConnect(DBM.java:12)
at service.ProductDaoImp.<init>(ProductDaoImp.java:10)
at service.Main.service(Main.java:17)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:619)


at service.ReadPro.readPrapertiesByName(ReadPro.java:17) 这行错内容如下:
in = new InputStreamReader(new FileInputStream("src/service/pro.properties"));

[分不分布式]

java.lang.NullPointerException at service.ProductDaoImp.findAll(ProductDaoImp.java:50) ProductDaoImp.findAll这里面出现了空指针异常了 所以你应该从这里面检查

[shixitong]

java.io.FileNotFoundException: src\service\pro.properties (系统找不到指定的路径。)

[huangxiaofei]

异常栈里已经写得挺清楚的了：java.io.FileNotFoundException: src\service\pro.properties (系统找不到指定的路径。) 看看你的pro.poperties是不是没放在指定的位置，或者文件名字有没有什么问题

[zkmhywgsym]

谢谢楼上的回答，我大概知道问题出在哪，但不知道为什么会出，是本地的和网络访问有什么不同吗？用main方法能访问，但用servet就不行

[zkmhywgsym]

引用 1 楼 sunlei198906 的回复:

java.lang.NullPointerException at service.ProductDaoImp.findAll(ProductDaoImp.java:50) ProductDaoImp.findAll这里面出现了空指针异常了 所以你应该从这里面检查

我也看到这个了，但是为什么用main方法能访问了，就是这不懂