文件的读写

package com.imecms.compare;

import java.io.*;
import java.util.ArrayList;

public class Test {
public static void main(String[] args) {
File f = new File("E:/test.txt");
try {
if(!f.exists()){
f.createNewFile();
}
String str = readTxtFile(f);
System.out.println(str);
String linStr = "DAAAAAAA";
saveToFile(linStr,"E:/test.txt");
String str1 = readTxtFile(f);
System.out.println(str1);
}catch (Exception e){
e.printStackTrace();
}

}
public static String readTxtFile(File file) throws Exception {
    String encoding = "UTF-8";
    StringBuffer sb = new StringBuffer();
    if (file.isFile() && file.exists()) { // 判断文件是否存在
        InputStreamReader read = new InputStreamReader(new FileInputStream(
                file), encoding);// 考虑到编码格式
        BufferedReader bufferedReader = new BufferedReader(read);
        String lineTxt = null;
        while ((lineTxt = bufferedReader.readLine()) != null) {
            sb.append(lineTxt + "\r\n");
        }
        read.close();
        return sb.toString();
    } else {
        throw new Exception("找不到指定的文件:" + file);
    }
}
public static void saveToFile(String contents, String filename)
        throws IOException {
    FileOutputStream fos = null;
    try {
        fos = new FileOutputStream(filename);
        fos.write(contents.getBytes("UTF-8"));
        fos.flush();
    } finally {
        if (fos != null) {
            fos.close();
        }
    }
}

}