import java.io.File;
import java.io.IOException;

import jxl.Cell;
import jxl.Sheet;
import jxl.Workbook;
import jxl.format.Border;
import jxl.format.BorderLineStyle;
import jxl.format.Colour;
import jxl.read.biff.BiffException;
import jxl.write.Label;
import jxl.write.WritableCellFormat;
import jxl.write.WritableFont;
import jxl.write.WritableSheet;
import jxl.write.WritableWorkbook;
import jxl.write.WriteException;
import jxl.write.biff.RowsExceededException;

/**
 *
 * CopyRight (C) www.blogjava.net/ilovezmh  All rights reserved.<p>
 *
 * WuHan Inpoint Information Technology Development,Inc.<p>
 *
 * Author zhu<p>
 *
 * @version 1.0    2007-2-6
 *
 * <p>Base on : JDK1.5<p>
 *
 */

public class JexcelSample {
 
 /**
  * 写excel文件
  *
  */
 public void writeExc(File filename){
  WritableWorkbook wwb = null;
  try
  {
   wwb = Workbook.createWorkbook(filename);   
  }
  catch (Exception e){
   e.printStackTrace();
  }
  
  //创建Excel工作表
  WritableSheet ws = wwb.createSheet("通讯录", 0);//创建sheet
  try {
   ws.mergeCells(0, 0, 2, 1);//合并单元格(左列，左行，右列，右行)从第1行第1列到第2行第3列
   Label header = new Label(0, 0, "通讯录(191026班)", getHeader());
   ws.addCell(header);//写入头
   Label l = new Label(0, 2, "姓名", getTitle());//第3行
   ws.addCell(l);
   l = new Label(1, 2, "电话", getTitle());
   ws.addCell(l);
   l = new Label(2, 2, "地址", getTitle());
   ws.addCell(l);
   l = new Label(0, 3, "小祝", getNormolCell());//第4行
   ws.addCell(l);
   l = new Label(1, 3, "1314***0974", getNormolCell());
   ws.addCell(l);
   l = new Label(2, 3, "武汉武昌", getNormolCell());
   ws.addCell(l);
   l = new Label(0, 4, "小施", getNormolCell());//第5行
   ws.addCell(l);
   l = new Label(1, 4, "1347***5057", getNormolCell());
   ws.addCell(l);
   l = new Label(2, 4, "武汉武昌", getNormolCell());
   ws.addCell(l);
   ws.setColumnView(0,20);//设置列宽
   ws.setColumnView(1,20);
   ws.setColumnView(2,40);
   ws.setRowView(0,400);//设置行高
   ws.setRowView(1,400);
   ws.setRowView(2,500);
   ws.setRowView(3,500);
   ws.setRowView(4,500);
  } catch (RowsExceededException e1) {
   e1.printStackTrace();
  } catch (WriteException e1) {
   e1.printStackTrace();
  }
  
  //输出流
  try {
   wwb.write();
  } catch (IOException ex) {
   // TODO 自动生成 catch 块
   ex.printStackTrace();
  }
  //关闭流
  try {
   wwb.close();
  } catch (WriteException ex) {
   // TODO 自动生成 catch 块
   ex.printStackTrace();
  } catch (IOException ex) {
   // TODO 自动生成 catch 块
   ex.printStackTrace();
  }
  //outStream.close();
  System.out.println("写入成功！\n");
 }
 
 public void readExc(File filename) throws BiffException, IOException{

    Workbook wb = Workbook.getWorkbook(filename);
    Sheet s = wb.getSheet(0);//第1个sheet
    Cell c = null;
    int row = s.getRows();//总行数
    int col = s.getColumns();//总列数
    for(int i=0;i<row;i++){
     for(int j=0;j<col;j++){
      c = s.getCell(j,i);
      System.out.print(c.getContents()+"  ");
     }
     System.out.println();
    }  
 }
 
 /**
  * 设置头的样式
  * @return
  */
 public static WritableCellFormat getHeader(){
  WritableFont font = new  WritableFont(WritableFont.TIMES, 24 ,WritableFont.BOLD);//定义字体
  try {
   font.setColour(Colour.BLUE);//蓝色字体
  } catch (WriteException e1) {
   // TODO 自动生成 catch 块
   e1.printStackTrace();
  }
  WritableCellFormat format = new  WritableCellFormat(font);
  try {
   format.setAlignment(jxl.format.Alignment.CENTRE);//左右居中
   format.setVerticalAlignment(jxl.format.VerticalAlignment.CENTRE);//上下居中
   format.setBorder(Border.ALL,BorderLineStyle.THIN,Colour.BLACK);//黑色边框
   format.setBackground(Colour.YELLOW);//黄色背景
  } catch (WriteException e) {
   // TODO 自动生成 catch 块
   e.printStackTrace();
  }
  return format;
 }
 
 /**
  * 设置标题样式
  * @return
  */
 public static WritableCellFormat getTitle(){
  WritableFont font = new  WritableFont(WritableFont.TIMES, 14);
  try {
   font.setColour(Colour.BLUE);//蓝色字体
  } catch (WriteException e1) {
   // TODO 自动生成 catch 块
   e1.printStackTrace();
  }
  WritableCellFormat format = new  WritableCellFormat(font);
  
  try {
   format.setAlignment(jxl.format.Alignment.CENTRE);
   format.setVerticalAlignment(jxl.format.VerticalAlignment.CENTRE);
   format.setBorder(Border.ALL,BorderLineStyle.THIN,Colour.BLACK);
  } catch (WriteException e) {
   // TODO 自动生成 catch 块
   e.printStackTrace();
  }
  return format;
 }
 
 /**
  * 设置其他单元格样式
  * @return
  */
 public static WritableCellFormat getNormolCell(){//12号字体,上下左右居中,带黑色边框
  WritableFont font = new  WritableFont(WritableFont.TIMES, 12);
  WritableCellFormat format = new  WritableCellFormat(font);
  try {
   format.setAlignment(jxl.format.Alignment.CENTRE);
   format.setVerticalAlignment(jxl.format.VerticalAlignment.CENTRE);
   format.setBorder(Border.ALL,BorderLineStyle.THIN,Colour.BLACK);
  } catch (WriteException e) {
   // TODO 自动生成 catch 块
   e.printStackTrace();
  }
  return format;
 }
 
 public static void main(String[] args) throws IOException, BiffException{
  JexcelSample js = new JexcelSample();
  File f = new File("D:\\address.xls");
  f.createNewFile();
  js.writeExc(f);
  js.readExc(f);
 }

}

生成的excel表格如下：

import java.io.InputStream;
import java.util.Properties;

/**
 *
 * CopyRight (C) www.blogjava.net/ilovezmh  All rights reserved.<p>
 *
 * WuHan Inpoint Information Technology Development,Inc.<p>
 *
 * Author zhu<p>
 *
 * @version 1.0    2007-2-2
 *
 * <p>Base on : JDK1.5<p>
 *
 */

public class ReadPro {
 
 public String getPara(String fileName) {
  
  Properties prop= new Properties();
  try {
   //ClassLoader cl = this.getClass().getClassLoader(); 
   //InputStream is = cl.getResourceAsStream(fileName);
   InputStream is = getClass().getResourceAsStream(fileName);
   prop.load(is);
   if(is!=null) is.close();
  }
  catch(Exception e) {
   System.out.println(e+"file "+fileName+" not found");
  }
  return prop.getProperty("ip");
 }
 
 public static void main(String[] args) {
  ReadPro pro = new ReadPro();
  System.out.println(pro.getPara("ip.property"));
 }
 
 //-----------------------------------
 //ip.property内容如下：
 //ip:192.168.0.1
 
}

用jdom读xml文件的例子：
(jdom下载)

package com.test;
import java.io.*;
import java.util.*;

import org.jdom.*;
import org.jdom.input.*;
import org.jdom.output.XMLOutputter;
import org.jdom.output.Format;

/**
 *
 * CopyRight (C) www.blogjava.net/ilovezmh All rights reserved.<p>
 *
 * WuHan Inpoint Information Technology Development,Inc.<p>
 *
 * Author zhu<p>
 *
 * @version 1.0    2007-2-1
 *
 * <p>Base on : JDK1.5<p>
 *
 */
 public class XMLReader {
 
  public void createXML(){
  
   Element root=new Element("books");
  
   Document doc=new Document(root);
   Element book1 = new Element("book");
   //Element name1=new Element("name");
   //name1.setAttribute(new Attribute("hot","true"));
   //name1.addContent("程序员");
   //Element price1=new Element("price");
   //price1.addContent("10.00");
   //book1.addContent(name1);
   //book1.addContent(price1); 
  
   Element book2 = new Element("book");
   //Element name2=new Element("name");
   //name2.setAttribute(new Attribute("hot","false"));
   //name2.addContent("读者");
   //Element price2=new Element("price");
   //price2.addContent("3.00");
   //book2.addContent(name2);
   //book2.addContent(price2);
     
   book1.addContent(new Element("name").addContent("程序员").setAttribute("hot","true"));
   book1.addContent(new Element("price").addContent("10.00"));
   book2.addContent(new Element("name").addContent("青年文摘").setAttribute("hot","false"));
   book2.addContent(new Element("price").addContent("3.00"));
   root.addContent(book1);
   root.addContent(book2);
  
   try
   {
    XMLOutputter outer=new XMLOutputter(Format.getPrettyFormat().setEncoding("gb2312"));
    outer.output(doc,new FileOutputStream("book.xml"));
   }catch(IOException e){
    e.printStackTrace();
   }
  }
 
  public void readXML() throws FileNotFoundException, IOException{
  
   Document myDoc=null;
   try
   {
    SAXBuilder sb=new SAXBuilder();
    myDoc=sb.build(new FileInputStream("book.xml"));
   }catch(JDOMException e){
    e.printStackTrace();
   }catch(NullPointerException e){
    e.printStackTrace();
   }
  
   Element root=myDoc.getRootElement(); //先得到根元素
   List books=root.getChildren();//root.getChildren("book"); 
   for (Iterator iter1 = books.iterator();iter1.hasNext(); ) {
       Element book = (Element) iter1.next();
       System.out.println("bookname:"+book.getChild("name").getText());
       System.out.println("hot:"+book.getChild("name").getAttributeValue("hot"));
       System.out.println("price:"+book.getChild("price").getText());
   }
  
  }
  
  public static void main(String args[]) throws FileNotFoundException, IOException {
  
   XMLReader x=new XMLReader();
   x.createXML();
   x.readXML();

 }

}

生成的book.xml文件如下:
<?xml version="1.0" encoding="gb2312"?>
<books>
  <book>
    <name hot="true">程序员</name>
    <price>10.00</price>
  </book>
  <book>
    <name hot="false">青年文摘</name>
    <price>3.00</price>
  </book>
</books>

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

/**
 *
 * CopyRight (C) http://www.blogjava.net/ilovezmh  All rights reserved.<p>
 *
 * WuHan Inpoint Information Technology Development,Inc.<p>
 *
 * Author zhu<p>
 *
 * @version 1.0    2007-1-17
 *
 * <p>Base on : JDK1.5<p>
 *
 */

public class City {
 
 static String driver1="sun.jdbc.odbc.JdbcOdbcDriver";
 static String driver2="net.sourceforge.jtds.jdbc.Driver";
 static String url1="jdbc:odbc:driver={Microsoft Access Driver (*.mdb)};DBQ=D:\\TDdownload\\area\\area.mdb";
 static String url2="jdbc:jtds:sqlserver://localhost:1433/test;SelectMethod=cursor;characterEncoding=GBK";
 
 public static void main(String arg[]) throws IOException,SQLException{
  
  
  Connection conn1=null;
  Connection conn2=null;
  Statement ps1=null;
  //Statement ps2=null;
  ResultSet rs1=null;
  //ResultSet rs2=null;
  String sql1=null;
  String sql2=null;
  PreparedStatement pstmt =null;
  
  try{
   Class.forName(driver1);
   Class.forName(driver2);
   conn1 = DriverManager.getConnection(url1,"","");
   conn2= DriverManager.getConnection(url2,"sa","sa");
   ps1 = conn1.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
   //ps2 = conn2.createStatement();
  }
  catch(ClassNotFoundException e){
   System.out.print(e);
  }
  catch (SQLException e) {
   // TODO 自动生成 catch 块
   e.printStackTrace();
  }
  
  try{   
   sql1="select * from area";
   rs1 = ps1.executeQuery(sql1);
   sql2 = "insert into tbcity(code,name,parentid,type) values (?,?,?,?)";
   pstmt=conn2.prepareStatement(sql2);
   
   int code=0;
   int parentid=0;
   String name=new String();
   while(rs1.next()){    
    code=rs1.getInt(2);
    name=rs1.getString(3);
    parentid=rs1.getInt(4);
    //sql2="insert into TBCITY(code,name,parentid,type) values ("+code+",'"+name+"',"+parentid+",3)";
    //ps2.executeUpdate(sql2);
    pstmt.setInt(1,code);
    pstmt.setString(2, name);
    pstmt.setInt(3,parentid);
    pstmt.setInt(4, 3);
    pstmt.addBatch();
   }   
   pstmt.executeBatch();    
     
   System.out.println("转换完成!谢谢使用");
   ps1.close();
   //ps2.close();
   pstmt.close();
   conn1.close();
   conn2.close();
  }
  catch(Exception e){
   System.out.print(e);
  }
  
 }
 
}

然后在命令行输入java -version，如果输出
java version "1.5.0_09"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_09-b03)
Java HotSpot(TM) Client VM (build 1.5.0_09-b03, mixed mode,sharing)

说明已经配置成功！

举例：
建立HelloWorld.java
public class HelloWorld{ 
       public static void main(String[] args) {  
           System.out.println("Hello World!"); 
       }
}

在当前目录命令行下输入执行javac HelloWorld.java
如果没有输出任何信息则说明编译成功。

再执行java HelloWorld，输出：
Hello World!
说明成功的执行了java程序。

再加个Tomcat的，每次配都不是很记得个名字。

CATALINA_HOME=c:\tomcat5;
CATALINA_BASE=c:\tomcat5;
然后修改环境变量中的classpath，把tomat安装目录下的common\lib下的servlet-api.jar(此文件在tomcat5以前名为：servlet.jar)追加到classpath中去，修改后的classpath如下：
classpath=.;%JAVA_HOME%\lib\dt.jar;%JAVA_HOME%\lib\tools.jar;%CATALINA_HOME%\common\lib\servlet-api.jar;