java操作文件，目录

**

* 输出目录中的所有文件及目录名字

* @param filePath

*/

public void readFolderByFile(String filePath)
{

File file = new File(filePath);
File[] tempFile = file.listFiles();
for(int i = 0;i<tempFile.length;i++)

{

if(tempFile[i].isFile())
{
System.out.println("File : "+tempFile[i].getName());
}

if(tempFile[i].isDirectory())
{
System.out.println("Directory : "+tempFile[i].getName());
}

}
2.如何用java修改文件的扩展名
File file=new File("c:/test.txt");
    file.renameTo(new File("c:/test.log"));
import java.io.*;

public class test1
{
   public static void main(String[] args) {
    File file=new File("c:/test.rtf"); //指定文件名及路径
    String filename=file.getAbsolutePath();
    if(filename.indexOf(".")>=0)
    {
      filename = filename.substring(0, filename.lastIndexOf("."));
    }
    file.renameTo(new File(filename+".doc")); //改名
  }

}
3.文件夹遍历
<%@ page contentType="text/html; charset=gb2312" %>
<%@ page import="java.io.*" %>
<%
String url1="C:/aaa";
File  f=(new File(url1));
if(f.isDirectory()){
       File [] fe = f.listFiles();
       go_on:
      for (int i = 0;i<fe.length;i++){
      if (fe[i].isDirectory()){                          
    File [] fe1 = fe[i].listFiles();
    for (int j = 0;j<fe1.length;j++){
    if (fe1[j].isDirectory())
    continue go_on;
    out.println(fe1[j].toString());
            }
        }                           
     else out.println(fe[i].toString());           
    }
  }

}
**
* 创建与删除文件
* @param filePath
* @param fileName
* @return 创建成功返回true
* @throws IOException
*/
public boolean createAndDeleteFile(String filePath,String fileName) throws IOException
{
boolean result = false;
File file = new File(filePath,fileName);
if(file.exists())
{
file.delete();
result = true;
System.out.println("文件已经删除！");
}
else
{
file.createNewFile();
result = true;
System.out.println("文件已经创建！");
}
return result;
}
/**
* 创建和删除目录
* @param folderName
* @param filePath
* @return 删除成功返回true
*/
public boolean createAndDeleteFolder(String folderName,String filePath)
{
boolean result = false;
try
{
File file = new File(filePath+folderName);
if(file.exists())
{
file.delete();
System.out.println("目录已经存在，已删除!");
result = true;
}
else
{
file.mkdir();
System.out.println("目录不存在，已经建立!");
result = true;
}
}
catch(Exception ex)
{
result = false;
System.out.println("CreateAndDeleteFolder is error:"+ex);
}
return result;
}
/**
* 输出目录中的所有文件及目录名字
* @param filePath
*/
public void readFolderByFile(String filePath)
{
File file = new File(filePath);
File[] tempFile = file.listFiles();
for(int i = 0;i<tempFile.length;i++)
{
if(tempFile[i].isFile())
{
System.out.println("File : "+tempFile[i].getName());
}
if(tempFile[i].isDirectory())
{
System.out.println("Directory : "+tempFile[i].getName());
}
}
}
/**
* 检查文件中是否为一个空
* @param filePath
* @param fileName
* @return 为空返回true
* @throws IOException
*/
public boolean fileIsNull(String filePath,String fileName) throws IOException
{
boolean result = false;
FileReader fr = new FileReader(filePath+fileName);
if(fr.read() == -1)
{
result = true;
System.out.println(fileName+" 文件中没有数据!");
}
else
{
System.out.println(fileName+" 文件中有数据!");
}
fr.close();
return result;
}
/**
* 读取文件中的所有内容
* @param filePath
* @param fileName
* @throws IOException
*/
public void readAllFile(String filePath,String fileName) throws IOException
{
FileReader fr = new FileReader(filePath+fileName);
int count = fr.read();
while(count != -1)
{
System.out.print((char)count);
count = fr.read();
if(count == 13)
{
fr.skip(1);
}
}
fr.close();
}
/**
* 一行一行的读取文件中的数据
* @param filePath
* @param fileName
* @throws IOException
*/
public void readLineFile(String filePath,String fileName) throws IOException
{
FileReader fr = new FileReader(filePath+fileName);
BufferedReader br = new BufferedReader(fr);
String line = br.readLine();
while(line != null)
{
System.out.println(line);
line = br.readLine();
}
br.close();
fr.close();
}
}


http://code.google.com/p/database-sharding/（拆分库和拆分表）