请问我的CONNECTION为什么不能creatstatement?

Question

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:346)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
root cause java.lang.NullPointerException
org.apache.jsp.liuyanben.ly_jsp._jspService(ly_jsp.java:75)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:298)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
note The full stack trace of the root cause is available in the Apache Tomcat/5.0.25 logs.

Answer 1

java.lang.NullPointerException
org.apache.jsp.liuyanben.ly_jsp._jspService(ly_jsp.java:75查看
%CATALINA_HOME%\work\Catalina\localhost\ROOT\org\apache\jsp\liuyanben\ly_jsp.java
第75行

Answer 2

空指针错误，可能是由于你的con没有初始化所引起的。

Answer 3

现在又变成了这个错误了，估计是数据库连接有问题。。？
javax.servlet.ServletException: [Microsoft][ODBC ???????] ???????????????????
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageContextImpl.java:825)
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:758)
org.apache.jsp.liuyanben.ly_jsp._jspService(ly_jsp.java:240)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:298)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
root cause java.sql.SQLException: [Microsoft][ODBC ???????] ???????????????????
sun.jdbc.odbc.JdbcOdbc.createSQLException(Unknown Source)
sun.jdbc.odbc.JdbcOdbc.standardError(Unknown Source)
sun.jdbc.odbc.JdbcOdbc.SQLDriverConnect(Unknown Source)
sun.jdbc.odbc.JdbcOdbcConnection.initialize(Unknown Source)
sun.jdbc.odbc.JdbcOdbcDriver.connect(Unknown Source)
java.sql.DriverManager.getConnection(Unknown Source)
java.sql.DriverManager.getConnection(Unknown Source)
wu.jdbc.executeQuery(jdbc.java:28)
org.apache.jsp.liuyanben.ly_jsp._jspService(ly_jsp.java:75)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:298)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
javax.servlet.http.HttpServlet.service(HttpServlet.java:810)

Answer 4

应该不是连接字符串的问题，因为报的是Statement stmt = con.createStatement()错误，应该是数据源有问题，

Answer 5

我大致写了个，你看看是否意思到位了（已经测试通过）：
public class TestBean{
  public static void main(String[] args) {
    try {
      Class.forName("oracle.jdbc.driver.OracleDriver");//这里用到的是什么数据库的driver就写相应的就可以
      String url = "jdbc:oracle:thin:@localhost:1521:数据库名称";
      String user = "...";
      String password = "....";
      Connection conn = DriverManager.getConnection(url, user, password);
      conn conn=new conn();
      Connection con=conn.getConn();
      Statement stmt = con.createStatement();
      String sql = "select..... ";
      ResultSet rs = stmt.executeQuery(sql);
      while (rs.next()) {
        System.out.println("first:"+rs.getString(1));
        System.out.println("second:"+rs.getString(2));
      }
      rs.close();
      stmt.close();
      con.close();
    }
    catch (Exception e) {
      e.printStackTrace();
      System.out.println("连接失败!");
    }  }
}

Answer 6

java.sql.SQLException: [Microsoft][ODBC ???????] ???????????????????后来这个确实是连接错误。另外它是Microsoft Odbc连接驱动.(嗯？不是jdbc也可以?)