package com.abin.facade.ws.mail.function;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.RandomAccessFile;

public class FileOperation {

/**
* 创建文件
* @param fileName
* @return
*/
public static boolean createFile(File fileName)throws Exception{
boolean flag=false;
try{
if(!fileName.exists()){
fileName.createNewFile();
flag=true;
}
}catch(Exception e){
e.printStackTrace();
}
return true;
}

/**
* 读TXT文件内容
* @param fileName
* @return
*/
public static String readTxtFile(File fileName)throws Exception{
String result=null;
FileReader fileReader=null;
BufferedReader bufferedReader=null;
try{
fileReader=new FileReader(fileName);
bufferedReader=new BufferedReader(fileReader);
try{
String read=null;
while((read=bufferedReader.readLine())!=null){
result=result+read+"\r\n";
}
}catch(Exception e){
e.printStackTrace();
}
}catch(Exception e){
e.printStackTrace();
}finally{
if(bufferedReader!=null){
bufferedReader.close();
}
if(fileReader!=null){
fileReader.close();
}
}
System.out.println("读取出来的文件内容是："+"\r\n"+result);
return result;
}


public static boolean writeTxtFile(String content,File fileName)throws Exception{
RandomAccessFile mm=null;
boolean flag=false;
FileOutputStream o=null;
try {
o = new FileOutputStream(fileName);
o.write(content.getBytes("GBK"));
o.close();
// mm=new RandomAccessFile(fileName,"rw");
// mm.writeBytes(content);
flag=true;
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}finally{
if(mm!=null){
mm.close();
}
}
return flag;
}

public static void contentToTxt(String filePath, String content) {
String str = new String(); //原有txt内容
String s1 = new String();//内容更新
try {
File f = new File(filePath);
if (f.exists()) {
System.out.print("文件存在");
} else {
System.out.print("文件不存在");
f.createNewFile();// 不存在则创建
}
BufferedReader input = new BufferedReader(new FileReader(f));

while ((str = input.readLine()) != null) {
s1 += str + "\n";
}
System.out.println(s1);
input.close();
s1 += content;

BufferedWriter output = new BufferedWriter(new FileWriter(f));
output.write(s1);
output.close();
} catch (Exception e) {
e.printStackTrace();

}
}

}

转自：http://blog.csdn.net/suplxj/article/details/7581715