文件操作类

package netforce;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.RandomAccessFile;
import java.io.Reader;

public class FileUtil {

/**
* 读取字节
* @param fileName
*/
public static void readFileByBytes(String fileName)
{
File file = new File(fileName);
InputStream in = null;
try
{
System.out.println("以字节为单位读取文件内容，一次读一个字节");
in = new FileInputStream(file);
int tempbyte;
while((tempbyte = in.read()) != -1)
{
System.out.write(tempbyte);
}
in.close();
}catch(IOException e)
{
e.printStackTrace();
return;
}
try
{
System.out.println("以字节为单位读取文件内容，一次读多个字节");
byte[] tempbytes = new byte[100];
int byteread = 0;
in = new FileInputStream(fileName);
FileUtil.showAvailableBytes(in);
while((byteread = in.read(tempbytes)) != -1)
{
System.out.write(tempbytes, 0, byteread);
}
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
if(in != null)
{
try
{
in.close();
}
catch(IOException e)
{
e.printStackTrace();
}
}
}
}

/**
* 读取字符
* @param fileName
*/
public static void readFileByChars(String fileName)
{
File file = new File(fileName);
Reader reader = null;
try
{
System.out.println("以字符为单位读取文件内容，一次读一个字符");
reader = new InputStreamReader(new FileInputStream(file));
//一次读一个字符
int tempchar;
while((tempchar = reader.read()) != -1)
{
if(((char)tempchar) != '\r')
{
System.out.print((char)tempchar);
}
}
reader.close();
}
catch(Exception e)
{
e.printStackTrace();
}
try
{
System.out.println("以字符为单位读取文件内容，一次读多个字符");
reader = new InputStreamReader(new FileInputStream(file));
char[] tempchars = new char[30];
//一次读一个字符
int charread = 0;
while((charread = reader.read(tempchars)) != -1)
{
//同样屏蔽掉\r不显示
if ((charread == tempchars.length)&&(tempchars[tempchars.length-1] != '\r'))
{
System.out.print(tempchars);
}
else
{
for(int i = 0; i < charread; i++)
{
if(tempchars[i] == '\r')
{
continue;
}
else
{
System.out.print(tempchars[i]);
}
}
}
}
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
if(reader != null)
{
try
{
reader.close();
}
catch(IOException e1)
{
e1.printStackTrace();
}
}
}
}

/**
* 读取行
* @param fileName
*/
public static void readFileByLines(String fileName)
{
File file = new File(fileName);
BufferedReader reader = null;
try
{
System.out.println("以行为单位读取文件内容");
reader = new BufferedReader(new FileReader(file));
//一次读一个字符
String tempString = null;
int line = 1;
while((tempString = reader.readLine()) != null)
{
System.out.println("line " + line + ": " + tempString);
line++;
}
reader.close();
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
if(reader != null)
{
try
{
reader.close();
}
catch(IOException e1)
{
e1.printStackTrace();
}
}
}
}

/**
* 随机读取
* @param fileName
*/
public static void readFileByRandomAccess(String fileName)
{
RandomAccessFile randomFile = null;
try
{
System.out.println("随机读取一段文件内容");
//打开一个随机访问文件流，按只读方式
randomFile = new RandomAccessFile(fileName, "r");
//文件长度，字节数
long fileLength = randomFile.length();
//读文件的起始位置
int beginIndex = (fileLength > 4) ? 4 : 0;
//将文件的开始位置移到beginIndex位置
randomFile.seek(beginIndex);
byte[] bytes = new byte[10];
int byteread = 0;
//一次读10个字节，如果文件内容不足10个字节，则读剩下的字节。
//将一次读取的字节数赋给byteread
while((byteread = randomFile.read(bytes)) != -1)
{
System.out.write(bytes, 0, byteread);
}
}
catch(IOException e)
{
e.printStackTrace();
}
finally
{
if(randomFile != null)
{
try
{
randomFile.close();
}
catch(IOException e1)
{
e1.printStackTrace();
}
}
}
}

/**
* 通过随机访问追加内容
* @param fileName
* @param content
*/
public static void appendToFileByRandomAccess(String fileName, String content)
{
try
{
RandomAccessFile randomFile = new RandomAccessFile(fileName, "rw");
long fileLength = randomFile.length();
randomFile.seek(fileLength);
randomFile.writeBytes(content);
randomFile.close();
}
catch(IOException e)
{
e.printStackTrace();
}
}

/**
* 通过FileWriter追加内容
* @param fileName
* @param content
*/
public static void appendToFileByFileWriter(String fileName, String content)
{
try
{
FileWriter writer = new FileWriter(fileName, true);
writer.write(content);
writer.close();
}
catch(IOException e)
{
e.printStackTrace();
}
}

private static void showAvailableBytes(InputStream in)
{
try
{
System.out.println("当前字节输入流中的字节数为" + in.available());
}
catch(IOException e)
{
e.printStackTrace();
}
}

/**
* 新建目录
* @param a
*/
public static void createFolder(String folderPath)
{
try
{
File filePath = new File(folderPath);
if(!filePath.exists())
{
filePath.mkdir();
}
System.out.println("新建目录成功");
}
catch(Exception e)
{
System.out.println("新建目录出错");
e.printStackTrace();
}
}

/**
* 新建文件
* @param a
*/
public static void createFile(String filePathAndName, String fileContent)
{
try
{
File filePath = new File(filePathAndName);
if(!filePath.exists())
{
filePath.createNewFile();
}
FileWriter writer = new FileWriter(filePath);
PrintWriter pw = new PrintWriter(writer);
pw.println(fileContent);
writer.close();
System.out.println("新建目录成功");
}
catch(Exception e)
{
System.out.println("新建目录出错");
e.printStackTrace();
}
}

/**
* 删除文件
* @param a
*/
public static void deleteFile(String filePathAndName)
{
try
{
File delFile = new File(filePathAndName);
delFile.delete();
System.out.println("删除文件成功");
}
catch(Exception e)
{
System.out.println("删除文件出错");
e.printStackTrace();
}
}

/**
* 删除空文件夹
*/
public static void delFolder(String folderPath)
{
try
{
delAllFile(folderPath);
File filePath = new File(folderPath);
if(filePath.delete())
{
System.out.println("删除文件夹" + folderPath + "操作 成功执行");
}
else
{
System.out.println("删除文件夹" + folderPath + "操作 执行失败");
}
}
catch(Exception e)
{
System.out.println("删除文件夹操作出错");
e.printStackTrace();
}
}

/**
* 删除文件夹里的所有文件
* @param a
*/
public static void delAllFile(String path)
{
File file = new File(path);
if(!file.exists())
{
return;
}
if(!file.isDirectory())
{
return;
}
String[] tempList = file.list();
File temp = null;
for(int i = 0; i < tempList.length; i++)
{
if(path.endsWith(File.separator))
{
temp = new File(path + tempList[i]);
}
else
{
temp = new File(path + File.separator + tempList[i]);
}
if(temp.isFile())
{
temp.delete();
}
if(temp.isDirectory())
{
delFolder(path + File.separatorChar + tempList[i]);
}
}
}

/**
* 复制单个文件
* @param a
*/
public static void copyFile(String oldFile, String newFile)
{
try
{
int byteSum = 0;
int byteRead = 0;
File oFile = new File(oldFile);
if(oFile.exists())
{
InputStream inStream = new FileInputStream(oldFile);
FileOutputStream fos = new FileOutputStream(newFile);
byte[] buffer = new byte[1024];
while((byteRead = inStream.read(buffer)) != -1)
{
byteSum += byteRead;
fos.write(buffer, 0, byteRead);
}
inStream.close();
}
}
catch(Exception e)
{
e.printStackTrace();
}
}

/**
* 复制整个文件夹
* @param a
*/
public static void copyFolder(String oldPath, String newPath)
{
try
{
(new File(newPath)).mkdirs();
File a = new File(oldPath);
String[] file = a.list();
File temp = null;
for(int i = 0; i < file.length; i++)
{
if(oldPath.endsWith(File.separator))
{
temp = new File(oldPath + file[i]);
}
else
{
temp = new File(oldPath + File.separator + file[i]);
}
if(temp.isFile())
{
FileInputStream input = new FileInputStream(temp);
FileOutputStream output = new FileOutputStream(newPath + "/" + (temp.getName()).toString());
byte[] b = new byte[1024 * 5];
int len;
while((len = input.read(b)) != -1)
{
output.write(b, 0, len);
}
output.flush();
output.close();
input.close();
}
if(temp.isDirectory())
{
copyFolder(oldPath + "/" + file[i], newPath + "/" + file[i]);
}
}
}
catch(Exception e)
{
e.printStackTrace();
}
}

/**
* 移动文件到目录
* @param a
*/
public static void moveFolder(String oldPath, String newPath)
{
copyFile(oldPath, newPath);
deleteFile(oldPath);
}

}

还不会，才搞这个博客的，请见谅