【略相关】亿能的JavaWeb高手们

【略相关】求助亿能的JavaWeb高手们
警告: StandardWrapperValve[jsp]: PWC1406: Servlet.service() for servlet jsp threw exception
可是我实在是不知道我的问题出在哪，我用工厂建的类，我觉得应该是建类没建成功？
这是我的config.properties
mlpUserDao=com.hxy.mlp.dao.MlpUserDao
mlpHomeDao=com.hxy.mlp.dao.MlpHomeDao
mlpCategoryDao=com.hxy.mlp.dao.MlpCategoryDao
mlpArticleDao=com.hxy.mlp.dao.MlpArticleDao
mlpReviewDao=com.hxy.mlp.dao.MlpReviewDao
mlpPictureDao=com.hxy.mlp.dao.MlpPictureDao
mlpMsgDao=com.hxy.mlp.dao.MlpMsgDao
mlpUserService=com.hxy.mlp.service.MlpUserService
mlpHomeService=com.hxy.mlp.service.MlpHomeService
mlpCategoryService=com.hxy.mlp.service.MlpCategoryService
mlpArticleService=com.hxy.mlp.service.MlpArticleService
mlpReviewService=com.hxy.mlp.service.MlpReviewService
mlpPictureService=com.hxy.mlp.service.MlpPictureService
mlpMsgService=com.hxy.mlp.service.MlpMsgService

StartServlet

Java code

/* * To change this template, choose Tools | Templates * and open the template in the editor. */package com.hxy.mlp.common;import java.io.FileInputStream;import java.io.InputStream;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;/** * * @author Arondight */public class StartServlet extends HttpServlet {    @Override    public void init() throws ServletException {        try {            String path = this.getServletContext().getRealPath("/WEB-INF/config.properties");            InputStream in = new FileInputStream(path);            Config.prop.load(in);        } catch (Exception ex) {            throw new ServletException(ex.getMessage());        }    }}

工厂类

Java code

/* * To change this template, choose Tools | Templates * and open the template in the editor. */package com.hxy.mlp.common;import com.hxy.mlp.idao.*;import com.hxy.mlp.iservice.*;/** * * @author Arondight */public class MyFactory {    private static Object getObject(String name) {        try {            String className = Config.prop.getProperty(name);            Object obj = Class.forName(className).newInstance();            return obj;        } catch (Exception ex) {            ex.printStackTrace();            return null;        }    }    public static IMlpUserDao createMlpUserDao() {        return (IMlpUserDao) getObject("mlpUserDao");    }    public static IMlpHomeDao createMlpHomeDao() {        return (IMlpHomeDao) getObject("mlpHomeDao");    }    public static IMlpCategoryDao createMlpCategoryDao() {        return (IMlpCategoryDao) getObject("mlpCategoryDao");    }    public static IMlpArticleDao createMlpArticleDao() {        return (IMlpArticleDao) getObject("mlpArticleDao");    }    public static IMlpReviewDao createMlpReviewDao() {        return (IMlpReviewDao) getObject("mlpReviewDao");    }    public static IMlpPictureDao createMlpPictureDao() {        return (IMlpPictureDao) getObject("mlpPictureDao");    }    public static IMlpMsgDao createMlpMsgDao() {        return (IMlpMsgDao) getObject("mlpMsgDao");    }    public static IMlpUserService createMlpUserService() {        return (IMlpUserService) getObject("mlpUserService");    }    public static IMlpHomeService createMlpHomeService() {        return (IMlpHomeService) getObject("mlpHomeService");    }    public static IMlpCategoryService createMlpCategoryService() {        return (IMlpCategoryService) getObject("mlpCategoryService");    }    public static IMlpArticleService createMlpArticleService() {        return (IMlpArticleService) getObject("mlpArticleService");    }    public static IMlpReviewService createMlpReviewService() {        return (IMlpReviewService) getObject("mlpReviewService");    }    public static IMlpPictureService createMlpPictureService() {        return (IMlpPictureService) getObject("mlpPictureService");    }    public static IMlpMsgService createMlpMsgService() {        return (IMlpMsgService) getObject("mlpMsgService");    }} 
 

XML code

<?xml version="1.0" encoding="UTF-8"?><!--To change this template, choose Tools | Templatesand open the template in the editor.--><!DOCTYPE web-appPUBLIC "-//Sun Microsystems,Inc.//DTD Web Application 2.3//EN""http://java.sun.com/dtd/web-app_2_3.dtd"><web-app>    <servlet>        <servlet-name>StartServlet</servlet-name>        <servlet-class>com.hxy.mlp.common.StartServlet</servlet-class>        <load-on-startup>0</load-on-startup>    </servlet>    <servlet-mapping>        <servlet-name>StartServlet</servlet-name>        <url-pattern>/StartServlet</url-pattern>    </servlet-mapping></web-app>

总是出空指针异常，也就是说工厂建对象失败了？为什么啊，困然了我好几天的问题，求高手解决。

[解决办法]
因為你的getObject發生錯誤時回傳null，所以之後就是NullPointException
想辦法取的getObject的錯誤訊息，就知道怎麼處理了。

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