大家帮我看看操作数据源的BEAN，错误在那里，先行谢谢了

有人能够给我一个这样的BEAN的原码吗？

Context ntx=(Context)ctx.lookup("java:comp/env");
ds = (DataSource)ntx.lookup("jdbc/sa");在你的配置文件中就没有见 comp/env ,,,,,
你是凭什么调用呀！
或者你在其他的地方做了说明！

我把我的出错再贴一遍吧：数据源配置：
<data-sources >
      <data-source key="org.apache.struts.action.DATA_SOURCE">
         <set-property property="password" value="ceshi" />
         <set-property property="minCount" value="1" />
         <set-property property="maxCount" value="10" />
         <set-property property="user" value="ceshi" />
         <set-property property="driverClass" value="com.microsoft.jdbc.sqlserver.SQLServerDriver" />
         <set-property property="description" value="SQLSERVER DATA_SOURCES" />
         <set-property property="url" value="jdbc:microsoft:sqlserver://127.0.0.1:1433;DatabaseName=eclipse" />
         <set-property property="readOnly" value="false" />
         <set-property property="autoCommit" value="false" />
         <set-property property="loginTimeout" value="10" />
      </data-source>   </data-sources>
连接的JAVABEAN：
package database;import java.sql.*;public class DBConn {
static Connection conn=null;
static ResultSet rs=null;
static Statement stmt=null;
public DBConn(){
}
public static void getConnection(javax.sql.DataSource datasource){
try{
conn=datasource.getConnection();

}catch(Exception e){
System.out.println(e.getMessage());
}
}

public void open(){
try{
stmt=conn.createStatement();
}
catch(Exception e){
System.out.println(e.getMessage());
}
}

public int getCount(String sql)
{
int getCount=0;

try
{
open();
rs=stmt.executeQuery(sql);
rs.last();
getCount=rs.getRow();

}
catch (SQLException ex)
{
System.out.println("sql.executeQuery:"+ex.getMessage());
}
return getCount;

}

public ResultSet Query(String sql){
open();
try {
rs = stmt.executeQuery(sql);
conn.close();
stmt.close();
}
catch(Exception ex) {
System.err.println(ex.getMessage());
}
return rs;
}

public void update(String sql)
{ open();
try
{
stmt.executeUpdate(sql);
conn.close();
stmt.close();
}
catch (Exception ex)
{
System.out.println("sql.executeQuery:"+ex.getMessage());
}
}
public void close(){
try{
rs.close();
stmt.close();
conn.close();
}
catch(Exception e){

}
}
}
调用的页面：
<%@page contentType="text/html;charset=gb2312"%>
<%@page language="java" import="java.sql.*" %>
<jsp:useBean id="db" scope="page" class="database.DBConn" />
<html>
<head>
<title>测试数据库</title>
</head>
<body bgcolor="#ffffff">
<table width="80%" border="0" align="center" bgcolor="#f2f2f2">
  <tr>
    <td height="19">
      <div align="center"><b>显示具体的信息 </b></div>
    </td>
  </tr>
</table>
<table width="80%" border="0" align="center">
  <tr>
    <td height="21">  </td>
  </tr>
</table>
<%
String sql;
sql="select * from ceshi";
ResultSet RS ;
RS=db.Query(sql);
try{
while(RS.next()){
%>
<table width="80%" border="0" align="center">
  <tr>
    <td height="21">编号: <%=RS.getString("id")%>
      <br>
      名称:<%=RS.getString("name")%>
    </td>
</tr>
</table>
<%
}
}
catch(Exception e){
out.println(e);
}
RS.close();
%>
</body>
</html>
所出现的错误：
type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:358)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
root cause java.lang.NullPointerException
org.apache.jsp.dbtest_jsp._jspService(dbtest_jsp.java:98)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:311)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
note The full stack trace of the root cause is available in the Tomcat logs.哪位高人帮我解决一下，马上揭贴送分

1:更改$CATALINA_HOME/conf/server.xml ，在<Context> 里面添加你的DataSource
  <Resource name="jdbc/example"
               auth="Container"
               type="javax.sql.DataSource"/>  <ResourceParams name="jdbc/example">
    <parameter>
      <name>factory</name>
      <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
    </parameter>    
    <parameter>
     <name>username</name>
     <value>ceshi</value>
    </parameter>
    <parameter>
     <name>password</name>
     <value></value>
    </parameter>
    
    <parameter>
       <name>driverClassName</name>
       <value>com.microsoft.jdbc.sqlserver.SQLServerDriver</value>
    </parameter>

    
    <parameter>
      <name>url</name>
      <value>jdbc:microsoft:sqlserver://127.0.0.1:1433;DatabaseName=eclipse</value>
    </parameter>

    
    <parameter>
      <name>maxActive</name>
      <value>100</value>
    </parameter>    
    <parameter>
      <name>maxIdle</name>
      <value>30</value>
    </parameter>    
    <parameter>
      <name>maxWait</name>
      <value>10000</value>
    </parameter>

  </ResourceParams>2:在你的web.xml最上面添加：
  <resource-ref>
      <description>DB Connection</description>
      <res-ref-name>jdbc/example</res-ref-name>
      <res-type>javax.sql.DataSource</res-type>
      <res-auth>Container</res-auth>
  </resource-ref>3：将你的DBConn该为.
package database;

package database;import org.apache.log4j.Logger;import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;public class DBConn {
    //-------------------------------------------------------------------------------------------
    // instance data
    //-------------------------------------------------------------------------------------------
    private static Logger logger = Logger.getLogger(DBConn.class);
    private static Connection connection;
    private static Statement statement;
    private static DataSource ds = null;    public DBConn() {
    }    //-------------------------------------------------------------------------------------------
    // static block to initial datasource
    //-------------------------------------------------------------------------------------------
    static {
        try {
            Context initCtx = new InitialContext();
            Context ctx = (Context) initCtx.lookup("java:comp/env");
            // Look up our data source
            logger.debug("getting DataSource using JNDI:jdbc/example");
            ds = (DataSource) ctx.lookup("jdbc/example");
            logger.debug(".........");
        } catch (NamingException e) {
            logger.error("NamingException:" + e.getMessage());
            e.printStackTrace();
        }
    }    //-------------------------------------------------------------------------------------------
    // public method
    //-------------------------------------------------------------------------------------------
    /**
     * @return Connection
     */
    public Connection getConnection()
            throws SQLException {
        logger.debug("DBConn.getConnection()");
        if (null == ds)
            return null;
        try {
            connection = ds.getConnection();
            logger.debug("successful get connection.");
        } catch (SQLException e) {
            logger.error("SQLException in DBConn.getConnection():" + e.getMessage());
            throw new SQLException("DBConn.getConnection() " + e.getMessage());
        }
        return connection;
    }    public int getCount(String sql) {
        logger.debug("DBConn.getCount()");
        ResultSet rs = null;
        int getCount = 0;
        try {
            statement = getConnection().createStatement();
            rs = statement.executeQuery(sql);
            rs.last();
            getCount = rs.getRow();
        } catch (SQLException ex) {
            logger.error("SQLException in DBConn.getCount():" + ex.getMessage());
            ex.printStackTrace();
        } finally {
            close(rs);
            close(statement);
            close(connection);
        }
        return getCount;
    }    /**
     * @param sql
     * @return
     */
    public ResultSet query(String sql) {
        logger.debug("DBConn.query()");
        ResultSet rs = null;
        try {
            statement = getConnection().createStatement();
            statement.executeQuery(sql);
        } catch (SQLException e) {
            logger.error("SQLException in DBConn.query():" + e.getMessage());
            e.printStackTrace();
        } finally {
            close(statement);
            close(connection);
        }
        return rs;
    }    /**
     * @param sql
     */
    public void update(String sql) {
        logger.debug("DBConn.update()");
        try {
            statement = getConnection().createStatement();
            statement.executeUpdate(sql);
        } catch (SQLException e) {
            logger.error("SQLException in DBConn.update():" + e.getMessage());
            e.printStackTrace();
        } finally {
            close(statement);
            close(connection);
        }
    }    //-------------------------------------------------------------------------------------------
    // private method
    //-------------------------------------------------------------------------------------------
    /**
     * @param o
     */
    private void close(Object o) {
        logger.debug("DBConn.close()");
        if (null == o)
            return;
        try {
            if (o instanceof Statement) {
                ((Statement) o).close();
            } else if (o instanceof Connection) {
                ((Connection) o).close();
            } else if (o instanceof ResultSet) {
                ((ResultSet) o).close();
            } else {
                logger.debug("NON");
            }
        } catch (SQLException e) {
            logger.error("SQLException in DBConn.close: " + e.getMessage());
            e.printStackTrace();
        }
    }
}

调试易

大家帮我看看操作数据源的BEAN，错误在那里，先行谢谢了

解决方案 »