OutputStream类（java.io.OutputStream）

public abstract class OutputStream extends Object implements Closeable, Flushable

Closeable:表示所有需要关闭的资源接口

Flushable:表示刷新处理

构造方法：public OutputStream()

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 class FileOutputStream extends OutputStream

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());

}

a.txt和b.txt原本不存在，自动生成。增加使用true参数，则在已经存在的文件尾追加。