java FileWriter 追加文件及文件改名方式

java FileWriter 追加文件及文件改名方式

FileWriter 追加文件及文件改名

我就废话不多说了，大家还是直接看代码吧~

import java.io.File;

KDIaJimport java.io.FileWriter;

import java.io.IOException;

public class FileWriterUtil {

/**

* 追加文件：使用FileWriter

*/

public static void appendMethod(String fileName, String content) {

try {

//打开一个写文件器，构造函数中的第二个参数true表示以追加形式写文件

FileWriter writer = new FileWriter(fileName, true);

writer.write(content);

writer.close();

} catch (IOException e) {

e.printStackTrace();

}

}

/**

* 修改文件名

* @param oldFilePath

* @param newFileName

*/

public static void reNameLogFile(String oldFilePath,String newFileName){

File f=new File(oldFilePath);

String c=f.getParent();

// File mm=new File(c + File.pathSeparator + newFileName + "_" + CommonUtil.getCurrTimeForString());

File mm=new File(c + "/" + newFileName + "_" + CommonUtil.getBeforeDateStr());

if(f.renameTo(mm)){

System.out.println("修改文件名成功!");

}else{

System.out.println("修改文件名失败");

}

}

public static void main(String[] args) {

String fileName = "/Users/qin/Downloads/callLog.txt";

String content = "new append!";

FileWriterUtil.appendMethod(fileName, content);

FileWriterUtil.appendMethod(fileName, "append end. \n");

FileWriterUtil.reNameLogFile("/Users/qin/Downloads/callLog.txt","rayda");

}

}

Java PrintWriter&FileWriter 写入追加到文件

用PrintWriter写入文件

import java.io.IOException;

import java.io.PrintWriter;

public class PrintWriteDemo

{

public static void main(String[] args) throws IOException

{

PrintWriter out = new PrintWriter("01.txt");

out.print("the quick brown fox");

out.println(" jumps over the lazy dog.");

out.write("work is like a capricious lover whose ");

out.write("incessant demands are resented but who is missed terribly when she is not there\n");

out.close(); //如果不关闭文件，文件停留在buffer zone, 不会写进"01.txt"中

}

}

FileWriter只能写入文件，无法往文件中追加内容

用FileWriter写入和追加文件

import java.io.IOException;

import java.io.FileWriter;

public class FileWriterDemo

{

public static void main(String[] args) throws IOException

{

FileWriter out = new FileWriter("02.txt");

//constructor中添加true,即FileWriter out = new FileWriter("02.txt", true)就是往02.txt中追加文件了

out.write("work is like a capricious lover whose ");

out.write("incessant demands are resented but who is missed terribly when she is not there\n");

out.write(98.7 + "\n");

out.close(); //很重要，一定记得关闭文件

}

}

都别忘记 throws IOException

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