jsp – 如何修复javax.naming.NamingException：查找失败

2023年11月5日 207次阅读

我试图通过一个简单的jsp表单来持久保存实体,但它不起作用.出现的异常是：
javax.naming.NamingException：’java：global / jee-projet-web’的查找失败.

我正在使用glasfish作为服务器.

这是我的表格代码：

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Add admin</title>
</head>
<body>
    <p id="info">
        ${info}
    </p>
    <form action="/jee-projet-web/AddAdmin" method="post">
    <fieldset>
        <label>Nom:</label>
        <input type="text" name="lastName" value="Entrez votre nom">
        <label>Prenom</label>
        <input type="text" name="name" value="Entrez votre prnom">
    </fieldset>
        <button type="submit">Ajouter</button>
    </form>
</body>
</html>

我的servlet AddAdmin：

package servlet.add;

import java.io.IOException;
import java.util.logging.Logger;

import javax.ejb.EJB;
import javax.ejb.LocalBean;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import model.Admin;
import model.databaseManager.AdminManager;
import model.databaseManager.Database;

@WebServlet(urlPatterns = {"/AdminAdd"})
@SuppressWarnings("serial")
public class AddAdmin extends HttpServlet{

    private AdminManager adminManager;

    @Override
    public void init() {
        Context context;
        try {
            context = new InitialContext();
            AdminManager adminManager = (AdminManager)context.lookup("java:global/jee-projet-web");
        } catch (NamingException e) {
            Logger.getLogger(this.getClass().getName()).warning("Erreur de contexte : Dans le nom");
            e.printStackTrace();
        }
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) 
            throws ServletException, IOException {
        response.setContentType("text/html; charset=iso-8859-15");

        String lName = request.getParameter("lastName");
        String name = request.getParameter("name");
        if(lName.equals("") || name.equals("")) {
            request.setAttribute("info", "Erreur: Un champ n'a pas été rempli");
            RequestDispatcher dispatcher =
                    getServletContext().getRequestDispatcher("/jsp/add/add.jsp");
            dispatcher.include(request, response);return;
        }

        Admin a = new Admin(lName, name);
        adminManager.addAdmin(a);
        request.setAttribute("info", "Admin ajouté");
        RequestDispatcher dispatcher =
                getServletContext().getRequestDispatcher("/jsp/add/add.jsp");
        dispatcher.include(request, response);return;
    }
}

我的实体bean Admin.java：

package model;

import java.io.Serializable;
import javax.persistence.*;


/**
 * The persistent class for the admin database table.
 * 
 */
@SuppressWarnings("serial")
@Entity
@Table(name="admin")
public class Admin implements Serializable {

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private int id;

    private String lastName;

    private String firstName;

    public Admin() {
    }

    public Admin(String lName, String fName) {
        this.firstName = fName;
        this.lastName = lName;
    }

    public int getId() {
        return this.id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getLastName() {
        return this.lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getFirstName() {
        return this.firstName;
    }

    public void setFirstName(String name) {
        this.firstName = name;
    }

}

我的managedBean：AdminManager

package model.databaseManager;

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.EntityTransaction;
import javax.persistence.Query;

import model.Admin;

public class AdminManager {
    private EntityManager entityManager = null;
    private EntityTransaction entityTransaction = null;

    @SuppressWarnings("static-access")
    public AdminManager(Database database) {
        entityManager = database.ENTITY_MANAGER;
        entityTransaction = database.ENTITY_TRANSACTION;
    }

    public void addAdmin(Admin admin) {
        entityTransaction.begin();
        entityManager.persist(admin);
        entityTransaction.commit();
    }

    public List<Admin> findAll() {
        Query query =
        entityManager.createQuery("select a from Admin a ");
        @SuppressWarnings("unchecked")
        List<Admin> liste = (List<Admin>)query.getResultList();     

        return liste;
    }

    public Admin findAdmin(int id) {
        Query query =
        entityManager.createQuery("select a from Admin a where a.id = :id");
        query.setParameter("id", id);       

        return (Admin) query.getSingleResult();
    }

    public boolean updateAdmin(Admin admin) {
        entityTransaction.begin();
        Query query =
        entityManager.createQuery("select a from Admin a where a.id = :id");
        query.setParameter("id", admin.getId());    
        if(query.getSingleResult()!=null) {
            entityManager.merge(admin);
            entityTransaction.commit();
            return true;
        }
        else return false;
    }

    public boolean deleteAdmin(int id) {
        entityTransaction.begin();
        Admin a = entityManager.find(Admin.class, id);
        if (a != null) {
            entityManager.remove(a);
            entityTransaction.commit();
            return true;
        }
        else return false;
    }

}

我的文件web.xml：

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">  

    <!-- Configuration jstl -->
    <context-param>
        <param-name>javax.servlet.jsp.jstl.sql.dataSource</param-name>
        <param-value>jdbc/data</param-value>
    </context-param>

    <!-- AddAdmin mapping -->
    <servlet>
        <servlet-name>AddAdmin</servlet-name>
        <servlet-class>servlet.add.AddAdmin</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>AddAdmin</servlet-name>
        <url-pattern>/AddAdmin</url-pattern>
    </servlet-mapping>  
 </web-app>

我的文件glassfish-web.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE glassfish-web-app PUBLIC "-//GlassFish.org//DTD GlassFish Application Server 3.1 Servlet 3.0//EN" "http://glassfish.org/dtds/glassfish-web-app_3_0-1.dtd">
<glassfish-web-app>
  <context-root>/jee-projet-web</context-root>
  <class-loader delegate="true"/>
  <jsp-config>
    <property name="keepgenerated" value="true">
      <description>Conserve une copie du code des servlets auto-générées.</description>
    </property>
  </jsp-config>
</glassfish-web-app>

我的文件persistence.xml

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
    <persistence-unit name="jee-projet" transaction-type="RESOURCE_LOCAL">
        <provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
        <class>model.Account</class>
        <class>model.Action</class>
        <class>model.Admin</class>
        <class>model.Client</class>
        <class>model.Transaction</class>
        <class>model.Wallet</class>
        <class>model.Company</class>
        <class>model.Bourse</class>
        <class>model.Participation</class>

    <properties>
    <property name="javax.persistence.jdbc.url" 
        value="jdbc:mysql://localhost:3306/jee"/>
    <property name="javax.persistence.jdbc.user" value="root"/>
    <property name="javax.persistence.jdbc.driver" 
        value="com.mysql.jdbc.Driver"/>
    <property name="javax.persistence.jdbc.password" value="root"/>
    <property name="eclipselink.ddl-generation" 
        value="drop-and-create-tables"/>
    <property name="eclipselink.logging.level" 
      value="FINEST"/>
  </properties>
    </persistence-unit>
</persistence>

我确信所有3个最后的文件都放在了正确位置.现在在这里运行我的程序是控制台中的错误：

2013-12-27T14:01:02.847+0100|Grave: javax.naming.NamingException: Lookup failed for 'java:global/jee-projet-web' in SerialContext[myEnv={java.naming.factory.initial=com.sun.enterprise.naming.impl.SerialInitContextFactory, java.naming.factory.state=com.sun.corba.ee.impl.presentation.rmi.JNDIStateFactoryImpl, java.naming.factory.url.pkgs=com.sun.enterprise.naming} [Root exception is javax.naming.NameNotFoundException: jee-projet-web not found]
    at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:491)
    at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:438)
    at javax.naming.InitialContext.lookup(InitialContext.java:411)
    at javax.naming.InitialContext.lookup(InitialContext.java:411)
    at servlet.add.AddAdmin.init(AddAdmin.java:33)
    at javax.servlet.GenericServlet.init(GenericServlet.java:244)
    at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1583)
    at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:1212)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:237)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:357)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:260)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:188)
    at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:191)
    at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:168)
    at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:189)
    at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:288)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:206)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:136)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:114)
    at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
    at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:838)
    at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:113)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:115)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:55)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:135)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:564)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:544)
    at java.lang.Thread.run(Thread.java:744)
Caused by: javax.naming.NameNotFoundException: jee-projet-web not found
    at com.sun.enterprise.naming.impl.TransientContext.doLookup(TransientContext.java:237)
    at com.sun.enterprise.naming.impl.TransientContext.lookup(TransientContext.java:204)
    at com.sun.enterprise.naming.impl.TransientContext.lookup(TransientContext.java:208)
    at com.sun.enterprise.naming.impl.SerialContextProviderImpl.lookup(SerialContextProviderImpl.java:66)
    at com.sun.enterprise.naming.impl.LocalSerialContextProviderImpl.lookup(LocalSerialContextProviderImpl.java:114)
    at com.sun.enterprise.naming.impl.SerialContext.lookup(SerialContext.java:478)
    ... 33 more
2013-12-27T14:01:02.872+0100|Avertissement: StandardWrapperValve[AddAdmin]: Servlet.service() for servlet AddAdmin threw exception
java.lang.NullPointerException
    at servlet.add.AddAdmin.doPost(AddAdmin.java:55)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:357)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:260)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:188)
    at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:191)
    at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:168)
    at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:189)
    at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:288)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:206)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:136)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:114)
    at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
    at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:838)
    at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:113)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:115)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:55)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:135)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:564)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:544)
    at java.lang.Thread.run(Thread.java:744)

感谢您的帮助.

最佳答案 在您已声明的AddAdmin servlet中

private AdminManager adminManager;

作为实例变量.在init()方法中,您再次使用同名创建问题来声明局部变量

更改

AdminManager adminManager = (AdminManager)context.lookup("java:global/jee-projet-web");

至

adminManager = (AdminManager)context.lookup("java:global/jee-projet-web");

现在,此行将值分配给adminManager

根本原因是

java.lang.NullPointerException
at servlet.add.AddAdmin.doPost(AddAdmin.java:55)

我想第55行是

adminManager.addAdmin(a);   //variable adminManager is not initialized

adminManager为null所以,调用null上的任何方法都会抛出NPE

更新

Root exception is javax.naming.NameNotFoundException: jee-projet-web not found

当名称的组件由于未绑定而无法解析时,将抛出This exception.

请确保名称jee-projet-web已经绑定.

我猜这是在jee-projet-web中丢失c的错字错误.它应该是jee-project-web.

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