at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.jav
a:927)
        at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.j
ava:890)
        at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:492
)
        at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1150)
        at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java
:311)
        at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(Lifecycl
eSupport.java:120)
        at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1022)

        at org.apache.catalina.core.StandardHost.start(StandardHost.java:736)
        at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1014)

        at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443
)
        at org.apache.catalina.core.StandardService.start(StandardService.java:4
48)
        at org.apache.catalina.core.StandardServer.start(StandardServer.java:700
)
        at org.apache.catalina.startup.Catalina.start(Catalina.java:552)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:295)
        at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:433)
Caused by: java.lang.IllegalArgumentException: Invalid <url-pattern> lookHello i
n servlet mapping
        at org.apache.catalina.core.StandardContext.addServletMapping(StandardCo
ntext.java:2327)
        at org.apache.catalina.core.StandardContext.addServletMapping(StandardCo
ntext.java:2303)
        ... 45 more
2009-5-7 10:37:50 org.apache.catalina.startup.ContextConfig applicationWebConfig

严重: Parse error in application web.xml file at jndi:/localhost/ch7/WEB-INF/web
.xml
java.lang.IllegalArgumentException: Invalid <url-pattern> lookHello in servlet m
apping
        at org.apache.tomcat.util.digester.Digester.createSAXException(Digester.
java:2726)
        at org.apache.tomcat.util.digester.Digester.createSAXException(Digester.
java:2752)
        at org.apache.tomcat.util.digester.Digester.endElement(Digester.java:106
1)
        at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.endEleme
nt(AbstractSAXParser.java:601)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImp
l.scanEndElement(XMLDocumentFragmentScannerImpl.java:1774)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImp
l$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2930)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(X
MLDocumentScannerImpl.java:648)
        at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImp
l.scanDocument(XMLDocumentFragmentScannerImpl.java:510)
        at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(X
ML11Configuration.java:807)
        at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(X
ML11Configuration.java:737)
        at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.
java:107)
        at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Ab
stractSAXParser.java:1205)
        at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.p
arse(SAXParserImpl.java:522)
        at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1562)
        at org.apache.catalina.startup.ContextConfig.applicationWebConfig(Contex
tConfig.java:348)
        at org.apache.catalina.startup.ContextConfig.start(ContextConfig.java:10
48)
        at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfi
g.java:261)
        at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(Lifecycl
eSupport.java:120)
        at org.apache.catalina.core.StandardContext.start(StandardContext.java:4
148)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase
.java:760)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:74
0)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:544)

        at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.jav
a:927)
        at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.j
ava:890)
        at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:492
)
        at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1150)
        at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java
:311)
        at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(Lifecycl
eSupport.java:120)
        at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1022)

        at org.apache.catalina.core.StandardHost.start(StandardHost.java:736)
        at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1014)

        at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443
)
        at org.apache.catalina.core.StandardService.start(StandardService.java:4
48)
        at org.apache.catalina.core.StandardServer.start(StandardServer.java:700
)
        at org.apache.catalina.startup.Catalina.start(Catalina.java:552)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:295)
        at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:433)
2009-5-7 10:37:50 org.apache.catalina.startup.ContextConfig applicationWebConfig

严重: Occurred at line 10 column 19
2009-5-7 10:37:50 org.apache.catalina.startup.ContextConfig start
严重: Marking this application unavailable due to previous error(s)
2009-5-7 10:37:50 org.apache.catalina.core.StandardContext start
严重: Error getConfigured
2009-5-7 10:37:50 org.apache.catalina.core.StandardContext start
严重: Context [/ch7] startup failed due to previous errors
2009-5-7 10:37:50 org.apache.coyote.http11.Http11BaseProtocol start
信息: Starting Coyote HTTP/1.1 on http-8080
2009-5-7 10:37:50 org.apache.jk.common.ChannelSocket init
信息: JK: ajp13 listening on /0.0.0.0:8009
2009-5-7 10:37:50 org.apache.jk.server.JkMain start
信息: Jk running ID=0 time=0/15  config=null
2009-5-7 10:37:50 org.apache.catalina.storeconfig.StoreLoader load
信息: Find registry server-registry.xml at classpath resource
2009-5-7 10:37:50 org.apache.catalina.startup.Catalina start
信息: Server startup in 1125 ms

import java.io.IOException;
import java.net.*;

public class f {

      public static void main(String[] args) {
      try {
    ServerSocket ss = new ServerSocket (8888);
    while(true) {
     Socket s = ss.accept();
System.out.println("a client connected!");
    }
   } catch (IOException e) {
    e.printStackTrace();
   }
 }

}

//package demo;
//打印斐波那契数列
public class Fib{
 public static void main(String[] args){
  int x = 0;
  int y = 1;

  System.out.print(x+" ");
     for(int i=1;i<=20;i++){
             System.out.print(y+" ");
                  y=x+y;
                  x=y-x;
     
              }
       }
}
其三：
//求出第n个数是几
public class Fib{
 public static void main(String args[]){
  System.out.println(f(6));
 }
 public static int f(int n){
  if(n == 1 || n == 2){
   return 1;
  }else{
   return f(n-1) + f(n-2);
  }
 }
}

package mydb;

import javax.swing.*;
import java.sql.*;

/**
 *
 * @author  soft
 */
class LoginJDialog extends javax.swing.JDialog {
   
    /** Creates new form LoginJDialog */
    private Connection cn;
    public Connection getCn() {
        return cn;
    }
    private void quit() {
        int tag = JOptionPane.showConfirmDialog(null, "您确定退出程序吗?", "信息", JOptionPane.YES_NO_OPTION);
 if(tag==JOptionPane.YES_OPTION){
  System.exit(1);
 }
    }
    private void getdata() {
        String uid = jTextField1.getText();
        String pwd = jPasswordField1.getText();
        int tag = 0;

        try{
  Class.forName("com.mysql.jdbc.Driver");
 }
 catch(ClassNotFoundException e){
  tag = 1;
 }
 try{
  cn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mytestdb",uid,pwd);
 }
 catch(SQLException e){
            tag = 1;
 }
        if(tag == 0) setVisible(false);
        else JOptionPane.showMessageDialog(this,"数据库错误!","错误",1);
    }
    public LoginJDialog(java.awt.Frame parent, boolean modal) {
        super(parent, modal);
        initComponents();

    }
   
    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    // <editor-fold defaultstate="collapsed" desc=" 生成的代码 ">                         
    private void initComponents() {
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jTextField1 = new javax.swing.JTextField();
        jPasswordField1 = new javax.swing.JPasswordField();
        jButton1 = new javax.swing.JButton();
        jButton2 = new javax.swing.JButton();

        setDefaultCloseOperation(javax.swing.WindowConstants.DO_NOTHING_ON_CLOSE);
        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowClosing(java.awt.event.WindowEvent evt) {
                formWindowClosing(evt);
            }
        });

        jLabel1.setText("User:");

        jLabel2.setText("password:");

        jButton1.setText("Cancel");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        jButton2.setText("Confirm");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton2ActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addGap(34, 34, 34)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addComponent(jLabel1)
                            .addComponent(jLabel2))
                        .addGap(16, 16, 16)
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                            .addComponent(jPasswordField1, 0, 0, Short.MAX_VALUE)
                            .addComponent(jTextField1, javax.swing.GroupLayout.DEFAULT_SIZE, 178, Short.MAX_VALUE)))
                    .addGroup(layout.createSequentialGroup()
                        .addContainerGap()
                        .addComponent(jButton1)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 126, Short.MAX_VALUE)
                        .addComponent(jButton2)))
                .addContainerGap())
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel1)
                    .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(29, 29, 29)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jLabel2)
                    .addComponent(jPasswordField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 51, Short.MAX_VALUE)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jButton1)
                    .addComponent(jButton2))
                .addContainerGap())
        );
        pack();
    }// </editor-fold>                       

    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                        
// TODO 将在此处添加您的处理代码：
                getdata();
    }                                       

    private void formWindowClosing(java.awt.event.WindowEvent evt) {                                  
// TODO 将在此处添加您的处理代码：
        quit();
    }                                 

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                        
// TODO 将在此处添加您的处理代码：
        quit();
    }                                       
   
    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new LoginJDialog(new javax.swing.JFrame(), true).setVisible(true);
            }
        });
    }
   
    // 变量声明 - 不进行修改                    
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JPasswordField jPasswordField1;
    private javax.swing.JTextField jTextField1;
    // 变量声明结束                  
   
}