Java创建TXT文件并进行读、写、修改操作

import java.io.*;

/**

*

* 功能描述：创建TXT文件并进行读、写、修改操作

*

*/

public class ReadWriteFile {

public static BufferedReader bufread;

//指定文件路径和名称

private static String path = "D:/suncity.txt";

private static File filename = new File(path);

private static String readStr ="";

/**

* 创建文本文件.

* @throws IOException

*

*/

public static void creatTxtFile() throws IOException{

if (!filename.exists()) {

filename.createNewFile();

System.err.println(filename + "已创建！");

}

}

/**

* 读取文本文件.

*

*/

public static String readTxtFile(){

String read;

FileReader fileread;

try {

fileread = new FileReader(filename);

bufread = new BufferedReader(fileread);

try {

while ((read = bufread.readLine()) != null) {

readStr = readStr + read+ "\r\n";

}

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

} catch (FileNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

System.out.println("文件内容是:"+ "\r\n" + readStr);

return readStr;

}

/**

* 写文件.

*

*/

public static void writeTxtFile(String newStr) throws IOException{

//先读取原有文件内容，然后进行写入操作

String filein = newStr + "\r\n" + readStr + "\r\n";

RandomAccessFile mm = null;

try {

mm = new RandomAccessFile(filename, "rw");

mm.writeBytes(filein);

} catch (IOException e1) {

// TODO 自动生成 catch 块

e1.printStackTrace();

} finally {

if (mm != null) {

try {

mm.close();

} catch (IOException e2) {

// TODO 自动生成 catch 块

e2.printStackTrace();

}

}

}

}

/**

* 将文件中指定内容的第一行替换为其它内容.

*

* @param oldStr

* 查找内容

* @param replaceStr

* 替换内容

*/

public static void replaceTxtByStr(String oldStr,String replaceStr) {

String temp = "";

try {

File file = new File(path);

FileInputStream fis = new FileInputStream(file);

InputStreamReader isr = new InputStreamReader(fis);

BufferedReader br = new BufferedReader(isr);

StringBuffer buf = new StringBuffer();

// 保存该行前面的内容

for (int j = 1; (temp = br.readLine()) != null

&& !temp.equals(oldStr); j++) {

buf = buf.append(temp);

buf = buf.append(System.getProperty("line.separator"));

}

// 将内容插入

buf = buf.append(replaceStr);

// 保存该行后面的内容

while ((temp = br.readLine()) != null) {

buf = buf.append(System.getProperty("line.separator"));

buf = buf.append(temp);

}

br.close();

FileOutputStream fos = new FileOutputStream(file);

PrintWriter pw = new PrintWriter(fos);

pw.write(buf.toString().toCharArray());

pw.flush();

pw.close();

} catch (IOException e) {

e.printStackTrace();

}

}

/**

* main方法测试

* @param s

* @throws IOException

*/

public static void main(String[] s) throws IOException {

ReadWriteFile.creatTxtFile();

ReadWriteFile.readTxtFile();

ReadWriteFile.writeTxtFile("20080808:12:13");

// ReadWriteFile.replaceTxtByStr("ken", "zhang");

}

}