java - 名称 [资源] 未在此上下文中绑定(bind)。找不到 [jdbc]

Question

我刚开始使用 JDBC 和 tomcat 连接到 MySQL。我一直在学习出色的教程 here但我很挣扎。我确保我的 EC2 安全组配置为 MYSQL 端口 3306 0.0.0.0/0 和 HTTP 端口 80 0.0.0.0/0。我目前收到错误:名称 [jdbc/bbytesting] 未绑定(bind)在此上下文中。找不到 [jdbc]。

这里是堆栈跟踪:

javax.naming.NameNotFoundException: Name [jdbc/bbytesting] is not bound in this Context. Unable to find [jdbc].
at org.apache.naming.NamingContext.lookup(NamingContext.java:818)
at org.apache.naming.NamingContext.lookup(NamingContext.java:166)
at org.apache.naming.SelectorContext.lookup(SelectorContext.java:157)
at javax.naming.InitialContext.lookup(InitialContext.java:417)
at com.youtube.dao.MySQL308tube.MySQL308tubeConn(MySQL308tube.java:31)
at com.youtube.rest.status.V1_status.returnDatabaseStatus(V1_status.java:61)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:185)
at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:302)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1542)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1473)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1419)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1409)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:409)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:558)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:733)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1526)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1482)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)

以下是我到目前为止执行的步骤:

下载MySQL JDBC Driver并放入lib文件夹

JDBC资源配置

<Context>

<Resource name="jdbc/bbytesting" auth="Container" type="javax.sql.DataSource"
           maxActive="50" maxIdle="30" maxWait="10000"
           username="username" password="password" 
           driverClassName="com.mysql.jdbc.Driver"
           url="jdbc:mysql://awsurl:3306/bbytesting">

 </Context>

返回数据库状态码:

    public String returnDatabaseStatus() throws Exception {

    PreparedStatement query = null;
    String myString = null;
    String returnString = null;
    Connection conn = null;  

    try {

        conn = MySQL308tube.MySQL308tubeConn().getConnection();
        query = conn.prepareStatement("select to_char(sysdate, 'YYYY-MM-DD HH24:MI:SS') DATETIME " + "from sys.dual");
        ResultSet rs = query.executeQuery(); 

        while (rs.next()) {
            myString = rs.getString("DATETIME");
        }

        query.close();

        returnString = "<p>Database Status</p> " 
        + "<Database Date/Time return: " + myString + "</p>";

    }
    catch (Exception e) {
        e.printStackTrace();
    }
    finally {
        if (conn != null) conn.close(); 
    }

    return returnString; 
    }

这里是连接类代码:

public class MySQL308tube {
     private static DataSource MySQL308tube = null;
     private static Context context = null;

     public static DataSource MySQL308tubeConn() throws Exception {

    if(MySQL308tube != null) {
        return MySQL308tube; 
    }

    try {

        if (context == null) {
            context = new InitialContext();
        }

        MySQL308tube = (DataSource) context.lookup("jdbc/bbytesting");

    }
    catch (Exception e) {
        e.printStackTrace();
    }

    return MySQL308tube;
}

}

Answer 1

异常完美地解释了它:这就是为什么你永远不应该有空的 catch block 。

您的 JNDI 数据源查找失败。你需要在它前面加上“java:/comp/env”，就像这些 Tomcat 文档告诉你的那样:

https://tomcat.apache.org/tomcat-7.0-doc/jndi-datasource-examples-howto.html