java - 为什么控制台给我 "Unable to find jdbc"

Question

我正在 Eclipse 中开发一个应用程序。那是maven项目。我想使用 phpMyAdmin MySqlDatabase。我在 src-main-resources 中创建了一个 META-INF 文件夹，并在该文件夹中创建了 context.xml 文件。这是我的 context.xml 文件:

    <?xml version="1.0" encoding="UTF-8"?>
<Context reloadable="true">
<Resource name="jdbc/mysql" auth="Container"   type="javax.sql.DataSource"
    driverClassName="com.mysql.jdbc.Driver" url="jdbc:mysql://localhost:3306/database?useUnicode=true&amp;characterEncoding=utf8&amp;"
username="root" password="" maxActive="20" maxIdle="10" maxWait="-1" />
</Context>

在 src-main-java 中，我制作了一个包，在其中制作了 DAO 类，这是我的 DAO 类:

public class OsobaDAO {
    private static String INSERTOSOBA = "INSERT INTO osoba (ime, prezime, JMBG) VALUES (?, ?, ?)";
    private static String DELETEOSOBA = "DELETE  FROM osoba WHERE idosoba = ?";
    private static String SELECTBYID = "SELECT * FROM osoba WHERE idosoba = ?"; private static String GETLASTNOSOBA = "SELECT * FROM osoba ORDER BY idosoba DESC LIMIT ? ";
    private DataSource ds;

    public OsobaDAO(){
        try {
            InitialContext cxt = new InitialContext();
            if ( cxt == null ) { 
            } 
            ds = (DataSource) cxt.lookup( "java:/comp/env/jdbc/mysql" ); 
            if ( ds == null ) { 

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

    public void insertOsoba(Osoba osoba){
        Connection con = null;
        java.sql.PreparedStatement pstm = null;
        try {
            con = ds.getConnection();
            pstm = con.prepareStatement(INSERTOSOBA);
            pstm.setString(1, osoba.getIme());
            pstm.setString(2, osoba.getPrezime());
            pstm.setString(3, osoba.getJMBG());
            pstm.execute();
        } catch (SQLException e) {
            System.out.println("Error connecting!");
        }
        try {
            con.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

此外，我有一个 jsp 文件，我正在其中测试从 DAO 插入的此方法:

<% OsobaDAO od = new OsobaDAO();

Osoba o = new Osoba("Pera", "Peric", "1111111111111");

// poziv metode
od.insertOsoba(o);
 %>

当我运行程序时出现此错误:

INFO: Server startup in 5862 ms
javax.naming.NameNotFoundException: Name [jdbc/mysql] is not bound in this Context. Unable to find [jdbc].
    at org.apache.naming.NamingContext.lookup(NamingContext.java:817)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:159)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:827)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:159)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:827)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:173)
    at org.apache.naming.SelectorContext.lookup(SelectorContext.java:163)
    at javax.naming.InitialContext.lookup(InitialContext.java:417)
    at dao.OsobaDAO.<init>(OsobaDAO.java:25)
    at org.apache.jsp.test_jsp._jspService(test_jsp.java:123)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:443)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:745)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    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)
Nov 22, 2016 2:00:13 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [jsp] in context with path [/DaoWithMaven] threw exception [java.lang.NullPointerException] with root cause
java.lang.NullPointerException
    at dao.OsobaDAO.insertOsoba(OsobaDAO.java:38)
    at org.apache.jsp.test_jsp._jspService(test_jsp.java:128)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:443)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:108)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:620)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:745)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    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)

有人可以帮助我吗？

Answer 1

@Atletica 使用此链接将会有很大帮助，如果答案可以，请投票 https://tomcat.apache.org/tomcat-6.0-doc/jndi-datasource-examples-howto.html