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StandardWrapperValve[jsp]: PWC1406: Servlet.service() for servlet jsp threw exception java.lang.NullPointerException

几天前我在这里问过同样的问题。克里斯为我指出了一些事情,但是在更改之后仍然出现错误,

还有什么我可以尝试的吗?

我已经上传了我的新代码。

我的第一个 JSP 页面加载正常,当我点击提交时出现错误。

“我不断收到这个警告,在一个非常简单的 JSP/Bean 页面上,我正在练习考试,但我无法通过这个。

有人能指出我的愚蠢吗?”

<html>
    <head>

        <title>JSP Page</title>
    </head>
    <h1>Enter Details!</h1>
    <body>
        <form action="Display.jsp" method="post">

            <center>
                Enter Name :<input type="text" name="Name"/><br/>
                Etv :<input type="radio" name="Channel" value="Etv" /><br/>
                Mnet :<input type="radio" name="Channel" value="Mnet" /><br/>
                Mtv :<input type="radio" name="Channel" value="Mtv" /><br/>
                FTV :<input type="radio" name="Channel" value="FTV" /><br/>
                Blue :<input type="checkbox" name="Blue" value="1" /><br/>
                Yellow :<input type="checkbox" name="Yellow" value="1" /><br/>
                Green :<input type="checkbox" name="Green" value="1" /><br/>
                Red :<input type="checkbox" name="Red" value="1" /><br/>
                <br/>
                <br/>

                <input type="submit" value="Submit" />
            </center>
        </form>

    </body>
</html>

我的Javabean:

package bean;

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

import java.beans.*;
import java.io.Serializable;

/**
 *
 * @author Ross
 */
public class NewBean implements Serializable {

    private String name;
    private String Channel;
    private int Blue;
    private int Yellow;
    private int Green;
    private int Red ;

    public NewBean() {

    }

     public NewBean(String tName,String tChannel,int tBlue,int tYellow,int tGreen,int tRed) {

    name=tName;
    Channel=tChannel;
    Blue=tBlue;
    Yellow=tYellow;
    Green=tGreen;
    Red=tRed;
    }

    public String getName(){
      return this.name;
    }
    public String getChannel(){
      return this.Channel;
    }
    public int getBlue(){
      return this.Blue;
    }
    public int getYellow(){
      return this.Yellow;
    }
    public int getGreen(){
      return this.Green;
    }
    public int getRed(){
      return this.Red;
    }
    public void setName(String tName){
      this.name = tName;
    }
    public void setChannel(String tChannel){
      this.Channel = tChannel;
    }
    public void setBlue(int tBlue){
      this.Blue = tBlue;
    }
    public void setYellow(int tYellow){
      this.Yellow = tYellow;
    }
    public void setGreen(int tGreen){
      this.Green = tGreen;
    }
    public void setRed(int tRed){
      this.Red = tRed;
    }
}

我的 JSP 显示 javabean:

<html>
    <head>

        <title>Display</title>
    </head>
    <body>
        <h1>Result</h1>
        <center>
            <jsp:useBean id="NewBean"class="bean.NewBean">

                <jsp:setProperty name="index" property="name" param="Name"/>
                <jsp:setProperty name="index" property="Channel" param="Channel"/>
                <jsp:setProperty name="index" property="Blue" param="Blue"/>
                <jsp:setProperty name="index" property="Yellow" param="Yellow"/>
                <jsp:setProperty name="index" property="Green" param="Green"/>
                <jsp:setProperty name="index" property="Red" param="Red"/>
            </jsp:useBean>
            <b>Displayed.</b>
             <jsp:getProperty name="index" property="Name"/>
             <jsp:getProperty name="index" property="Channel"/>
             <jsp:getProperty name="index" property="Blue"/>
             <jsp:getProperty name="index" property="Yellow"/>
             <jsp:getProperty name="index" property="Green"/>
             <jsp:getProperty name="index" property="Red"/>
        </center>

    </body>
</html>

Glassfish 3 服务器输出

19 Nov 2012 9:51:05 AM com.sun.enterprise.glassfish.bootstrap.ASMain main
INFO: Launching GlassFish on Felix platform
Welcome to Felix
================
INFO: Perform lazy SSL initialization for the listener 'http-listener-2'
INFO: Starting Grizzly Framework 1.9.18-o - Mon Nov 19 09:51:10 CAT 2012
INFO: Starting Grizzly Framework 1.9.18-o - Mon Nov 19 09:51:10 CAT 2012
INFO: Grizzly Framework 1.9.18-o started in: 140ms listening on port 7676
INFO: Grizzly Framework 1.9.18-o started in: 210ms listening on port 8080
INFO: Grizzly Framework 1.9.18-o started in: 170ms listening on port 4848
INFO: Grizzly Framework 1.9.18-o started in: 160ms listening on port 3700
INFO: Grizzly Framework 1.9.18-o started in: 180ms listening on port 8181
INFO: Using com.sun.enterprise.transaction.jts.JavaEETransactionManagerJTSDelegate as the delegate
INFO: SEC1002: Security Manager is OFF.
INFO: Security startup service called
INFO: SEC1143: Loading policy provider com.sun.enterprise.security.provider.PolicyWrapper.
INFO: Realm admin-realm of classtype com.sun.enterprise.security.auth.realm.file.FileRealm successfully created.
INFO: Realm file of classtype com.sun.enterprise.security.auth.realm.file.FileRealm successfully created.
INFO: Realm certificate of classtype com.sun.enterprise.security.auth.realm.certificate.CertificateRealm successfully created.
INFO: Security service(s) started successfully....
INFO: Created HTTP listener http-listener-1 on port 8080
INFO: Created HTTP listener http-listener-2 on port 8181
INFO: Created HTTP listener admin-listener on port 4848
INFO: Created virtual server server
INFO: Created virtual server __asadmin
INFO: Virtual server server loaded system default web module
INFO: Loading application InputAndDisplay at /InputAndDisplay
INFO: Loading InputAndDisplay Application done is 4951 ms
INFO: GlassFish Server Open Source Edition 3.0.1 (22) startup time : Felix(4501ms) startup services(6362ms) total(10863ms)
INFO: Binding RMI port to *:8686
INFO: Hibernate Validator bean-validator-3.0-JBoss-4.0.2
INFO: Instantiated an instance of org.hibernate.validator.engine.resolver.JPATraversableResolver.
INFO: JMXStartupService: Started JMXConnector, JMXService URL = service:jmx:rmi://192.168.2.11:8686/jndi/rmi://192.168.2.11:8686/jmxrmi
INFO: Created HTTP listener http-listener-1 on port 8080
INFO: Grizzly Framework 1.9.18-o started in: 10ms listening on port 8080
INFO: [Thread[GlassFish Kernel Main Thread,5,main]] started
INFO: {felix.fileinstall.poll (ms) = 5000, felix.fileinstall.dir = C:\glassfishv3\glassfish\domains\domain1\autodeploy\bundles, felix.fileinstall.debug = 1, felix.fileinstall.bundles.new.start = true, felix.fileinstall.tmpdir = C:\Users\Ross\AppData\Local\Temp\fileinstall--1537292188207799339, felix.fileinstall.filter = null}
INFO: {felix.fileinstall.poll (ms) = 5000, felix.fileinstall.dir = C:\glassfishv3\glassfish\modules\autostart, felix.fileinstall.debug = 1, felix.fileinstall.bundles.new.start = true, felix.fileinstall.tmpdir = C:\Users\Ross\AppData\Local\Temp\fileinstall--8697136160454616714, felix.fileinstall.filter = null}
INFO: Perform lazy SSL initialization for the listener 'http-listener-2'
INFO: Created HTTP listener http-listener-2 on port 8181
INFO: Grizzly Framework 1.9.18-o started in: 0ms listening on port 8181
INFO: Updating configuration from org.apache.felix.fileinstall-autodeploy-bundles.cfg
INFO: Installed C:\glassfishv3\glassfish\modules\autostart\org.apache.felix.fileinstall-autodeploy-bundles.cfg
INFO: {felix.fileinstall.poll (ms) = 5000, felix.fileinstall.dir = C:\glassfishv3\glassfish\domains\domain1\autodeploy\bundles, felix.fileinstall.debug = 1, felix.fileinstall.bundles.new.start = true, felix.fileinstall.tmpdir = C:\Users\Ross\AppData\Local\Temp\fileinstall--8665764141947736823, felix.fileinstall.filter = null}
WARNING: StandardWrapperValve[jsp]: PWC1406: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
        at org.apache.jasper.runtime.JspRuntimeLibrary.internalIntrospecthelper(JspRuntimeLibrary.java:363)
        at org.apache.jasper.runtime.JspRuntimeLibrary.introspecthelper(JspRuntimeLibrary.java:349)
        at org.apache.jsp.Display_jsp._jspService(Display_jsp.java from :63)
        at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:109)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
        at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:406)
        at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:483)
        at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:373)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
        at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188)
        at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641)
        at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97)
        at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185)
        at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226)
        at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165)
        at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
        at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
        at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
        at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
        at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
        at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
        at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
        at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
        at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
        at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
        at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
        at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
        at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
        at java.lang.Thread.run(Thread.java:662)

INFO: Total number of available updates : 49
INFO: Number of available updates since Fri Nov 16 09:47:00 CAT 2012 : 0
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1 回答 1

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java.lang.NullPointerException看来你还没有初始化NewBean。让我们

NewBean bean = new NewBean();
bean.setName(tname);//that *tname* is string from input box with ID = NAME
.....
于 2012-11-19T08:25:25.020 回答