public abstract void write(int b)throws IOException

输出单个字节

public void write(byte[] b)throws IOException

输出整个字节数组的数据

public void write(byte[] b,int off,int len)throws IOException

输出部分字节数组的数据

public void close()throws IOException

关闭输出流

public FileOutputStream(File file) throws FileNotFoundException

覆盖式输出文件（用File类）

public FileOutputStream(File file, boolean append) throws FileNotFoundException

追加式输出文件（用File类）

public FileOutputStream(String name) throws FileNotFoundException

覆盖式输出文件（用String类）

public FileOutputStream(String name, boolean append) throws FileNotFoundException

追加式输出文件（用String类）

package wiki.jjcc.test.ops;

import java.io.File;

import java.io.FileOutputStream;

import java.io.OutputStream;

publicclass Test1 {

    publicstaticvoid main(String[] args) throws Exception {

        String s = File.separator;

        File file = new File("D:"+ s + "test" + s + "a.txt");

        if(!file.getParentFile().exists()){

            file.getParentFile().mkdirs();

        }

        String msg = "Hello World!\r\n";

        OutputStream out11 = new FileOutputStream(file);

        out11.write(msg.getBytes());

        OutputStream out12 = new FileOutputStream(file,true);

        out12.write(msg.getBytes());

        OutputStream out21 = new FileOutputStream("D:"+ s + "test" + s + "b.txt");

        out21.write(msg.getBytes());

        OutputStream out22 = new FileOutputStream("D:"+ s + "test" + s + "b.txt",true);

        out22.write(msg.getBytes());

    }

}