javax.naming.NameNotFoundException:名称[comp/env]在此上下文中未绑定.使用Java Scheduler无法找到[comp]错误 [英] javax.naming.NameNotFoundException: Name [comp/env] is not bound in this Context. Unable to find [comp] error with java scheduler

问题描述

我要尝试的是在一段时间后更新数据库.所以我正在使用Java调度程序和连接池.我不知道为什么，但是我的代码只能运行一次.它将打印:

What I'm trying to do is to update my database after a period of time. So I'm using java scheduler and connection pooling. I don't know why but my code only working once. It will print:

init success
success
javax.naming.NameNotFoundException: Name [comp/env] is not bound in this Context. Unable to find [comp].
    at org.apache.naming.NamingContext.lookup(NamingContext.java:820)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:168)
    at org.apache.naming.SelectorContext.lookup(SelectorContext.java:158)
    at javax.naming.InitialContext.lookup(InitialContext.java:411)
    at test.Pool.main(Pool.java:25)  ---> line 25 is Context envContext = (Context)initialContext.lookup("java:/comp/env");

我不知道为什么它只能运行一次.如果没有Java调度程序就没有运行它，我已经对其进行了测试，并且可以正常工作.没有错误.不知道为什么使用调度程序运行此错误.

I don't know why it only works once. I already test it if I didn't running it without java scheduler and it works fine. No error whatsoerver. Don't know why i get this error if I running it using scheduler.

希望有人可以帮助我.

我的连接池代码:

public class Pool {
public DataSource main() {
    try {
        InitialContext initialContext = new InitialContext();
        Context envContext = (Context)initialContext.lookup("java:/comp/env");
        DataSource datasource = new DataSource();   
        datasource = (DataSource)envContext.lookup("jdbc/test");
        return datasource;
    } catch (Exception ex) {
        ex.printStackTrace();
    }
    return null;
}

}

我的web.xml :

<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">
<listener>
    <listener-class> package.test.Pool</listener-class>
</listener>
<resource-ref>
    <description>DB Connection Pooling</description>
    <res-ref-name>jdbc/test</res-ref-name>
    <res-type>javax.sql.DataSource</res-type>
    <res-auth>Container</res-auth>
</resource-ref>

Context.xml:

    <?xml version="1.0" encoding="UTF-8"?>
<Context path="/project" reloadable="true">
  <Resource auth="Container" 
            defaultReadOnly="false" 
            driverClassName="com.mysql.jdbc.Driver" 
            factory="org.apache.tomcat.jdbc.pool.DataSourceFactory" 
            initialSize="0" 
            jdbcInterceptors="org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer" 
            jmxEnabled="true" 
            logAbandoned="true" 
            maxActive="300" maxIdle="50"
            maxWait="10000" 
            minEvictableIdleTimeMillis="300000"
            minIdle="30" 
            name="jdbc/test"
            password="test" 
            removeAbandoned="true"
            removeAbandonedTimeout="60" 
            testOnBorrow="true"
            testOnReturn="false" 
            testWhileIdle="true" 
            timeBetweenEvictionRunsMillis="30000"
            type="javax.sql.DataSource" 
            url="jdbc:mysql://localhost:3306/database?noAccessToProcedureBodies=true" 
            username="root"
            validationInterval="30000" 
            validationQuery="SELECT 1"/>
</Context>

我的Java调度程序

public class Scheduler extends HttpServlet{

public void init() throws ServletException
{
    System.out.println("init success");
    try{
        Scheduling_test test = new Scheduling_test();
        ScheduledExecutorService executor = Executors.newScheduledThreadPool(100);
        ScheduledFuture future = executor.scheduleWithFixedDelay(test, 1, 60 ,TimeUnit.SECONDS);
    }catch(Exception e){
         e.printStackTrace();
    }
}

}

Schedule_test

    public class Scheduling_test extends Thread implements Runnable{
    public void run(){
        Updating updating = new Updating();
        updating.run();
    }
}

更新

public class Updating{

        public void run(){
            ResultSet rs = null;
            PreparedStatement  p = null;
            StringBuilder sb = new StringBuilder();
            Pool pool = new Pool();
            Connection con = null; 
            DataSource datasource = null;
            try{
                datasource = pool.main();
                con=datasource.getConnection();
                sb.append("SELECT * FROM database");
                p = con.prepareStatement(sb.toString());
                rs = p.executeQuery();
                rs.close();
                con.close();
                p.close();
                datasource.close();
                System.out.println("success");
         }catch (Exception e){
                e.printStackTrace();
         }
    }

推荐答案

此错误表明您的 jdbc 资源未注册 ！您将 context.xml 放在哪里?

This error shows that your jdbc resource is not registered! Where did you put your context.xml?

context.xml 文件必须位于war文件的 META-INF 目录中.它不能在 classes目录或 jar 文件中.

The context.xml file must be in the META-INF directory of the war file. It must not be in the classes directory or in a jar file.

将 META-INF 目录与 context.xml 放入包含 webapp root 的目录中>在您的源文件夹树中.

Put the META-INF directory with the context.xml in the directory containing the root of the webapp in your source folder tree.

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