Java I/O 教程（三） FileOutputStream类

Java FileOutputStream 用于将字节数据写入文件。

如果你需要将原始数据写入文件，就使用FileOutputStream类。

Java.io.FileOutputStream class声明如下:

public class FileOutputStream extends OutputStream

构造函数

FileOutputStream(File file)
Creates a file output stream to write to the file represented by the specified File object.

FileOutputStream(String name)
Creates a file output stream to write to the file with the specified name.

FileOutputStream(String name, boolean append)
Creates a file output stream to write to the file with the specified name.

常用函数

void write(byte[] ary)                       往文件输出流写指定字节数组
void write(byte[] ary, int off, int len)   往文件输出流写指定长度字节数组
void write(int b)                           往文件输出流写指定字节
void close()                               关闭文件输出流

例子1：

package com.dylan.io;

import java.io.FileOutputStream;

/**
 * @author xusucheng
 * @create 2017-12-31
 **/
public class FileOutputStreamWriteByte {
    public static void main(String[] args) {
        try {
            FileOutputStream fout = new FileOutputStream("D:\\testout.txt");
            fout.write(65);
            fout.close();
            System.out.println("success...");
        } catch (Exception e) {
            System.out.println(e);
        }
    }
}

例子2：

package com.dylan.io;

import java.io.FileOutputStream;

/**
 * @author xusucheng
 * @create 2017-12-31
 **/
public class FileOutputStreamWriteString {
    public static void main(String[] args) {
        try {
            FileOutputStream fout = new FileOutputStream("D:\\testout.txt",true);
            String s = "Welcome to java.io.";
            byte b[] = s.getBytes(); //将字符串转为字节数组
            fout.write(b);
            fout.close();
            System.out.println("写入成功！");
        } catch (java.io.IOException e) {
            e.printStackTrace();
        }
    }
}