FileOutputStream

package file;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

public class Demo2 {
public static void main(String[] args) throws IOException {
//        writeTest1();
//        writeTest2();
writeTest3();
}

//使用字节数组把数据写出
public static void writeTest3() throws IOException   {
File file = new File("F:/2.txt");
FileOutputStream fileOutputStream = new  FileOutputStream(file);
//数据写出
String data = "abcd";
byte[] buf = data.getBytes();
fileOutputStream.write(buf, 0, 2);    //写出2个字节
fileOutputStream.close();
}

//使用字节数组把数据写出
public static void writeTest2() throws IOException   {
File file = new File("F:/2.txt");
//使用FileOutputStream(File)，如果文件不存在，会自动创建目标文件。如果存在，则会先把目标文件的内容清空，再写内容
//使用FileOutputStream(File，true)构造函数，则会在末尾追加
FileOutputStream fileOutpubStream = new FileOutputStream(file);
//数据写出
String data = "hello world";
fileOutpubStream.write(data.getBytes());
//关闭资源
fileOutpubStream.close();
}

//每次只能写一个字节数据
public static void writeTest1() throws IOException   {
File file = new File("F:\\2.txt");
FileOutputStream fileOutpubStream = new FileOutputStream(file);
fileOutpubStream.write('h');
fileOutpubStream.write('e');
fileOutpubStream.write('l');
fileOutpubStream.write('l');
fileOutpubStream.write('o');

fileOutpubStream.close();
}
}