黑马程序员 java学习笔记3-IO流之字节流与装饰设计模式

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装饰设计模式：

当想要对已有的对象功能进行增强时，可以定义一个类，将已有对象传入，基于已有的功能，并提供加强功能，那么该自定义的类就称为装饰类。

装饰类通常会以构造方法的方式接收需要被装饰的类。

class Person{

public void chifan(){

System.out.println("吃饭");

}

}

class SuperPerson{

private Person p;

SuperPerson(Person p){

this.p = p;

}

public void superchifan(){

System.out.println("喝酒");

p.chifan();

System.out.println("吃水果");

}

}

public class Test1 {

/**

* @param args

*/

public static void main(String[] args) {

// TODO Auto-generated method stub

Person p = new Person();

SuperPerson sp = new SuperPerson(p);

sp.superchifan();

}

}

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（2）、字节流

InputStream（读），OutputStream（写）

public static void main(String[] args) throws Exception {

// TODO Auto-generated method stub

// writerStream3(); // 一般情况下 不建议使用这种定义一个大小刚好的数组方式。

readerStream2();

}



public static void readerStream3() throws Exception

{

FileInputStream fin = new FileInputStream("E:\\aa.txt");

byte [] by = new byte[fin.available()]; //定义一个大小刚好的缓冲区

int num = fin.read(by);

System.out.println(new String(by,0,num));

}

public static void readerStream2() throws Exception

{

FileInputStream fin = new FileInputStream("E:\\aa.txt");

byte [] buf = new byte[1024];

int num = 0;

while((num=fin.read(buf))!=-1)

{

System.out.println(new String(buf,0,num));

}

fin.close();

}

public static void writerStream() throws Exception

{

FileOutputStream fout = new FileOutputStream("E:\\aa.txt",true);

fout.write("我爱你".getBytes());

fout.close();

}

2。

FileOutputStream fw = null;

FileInputStream fi = null;

try {

fi = new FileInputStream("E:\\Project1.exe");

fw = new FileOutputStream("E:\\copy_Project1.exe");



byte [] buf = new byte[1024];

int num = 0;

while((num=fi.read(buf))!=-1)

{

fw.write(buf);

}



} catch (Exception e) {

// TODO Auto-generated catch block

System.out.println(e.toString());

}

finally

{

if(fw!=null)

{

try {

fw.close();

} catch (IOException e) {

// TODO Auto-generated catch block

throw new RuntimeException("复制文件失败");

}

}

if(fi!=null)

{

try {

fi.close();

} catch (IOException e) {

// TODO Auto-generated catch block

System.out.println(e.toString());

}

}

}

（3）、读取键盘录入

InputStream in = System.in;

StringBuilder sb = new StringBuilder();

while(true)

{

int iread = in.read();

if(iread=='\r')

{

continue;

}

if(iread=='\n')

{

String s = sb.toString();



if(s.equals("over")) //当输入“over”时结束

return;

System.out.println(s);

sb.delete(0, sb.length()); //清空缓冲区

}else{

sb.append((char)iread);

}

}

-----------------例子二---------------------------------

//获取键盘录入对象

InputStream in = System.in;

//将字节流对象转换成字符流对象，使用转换流

InputStreamReader isr = new InputStreamReader(in);

//为了提高效率，将字符串进行缓冲区技术高校操作，使用BufferedReader

BufferedReader bufr = new BufferedReader(isr);

String line = null;

while((line=bufr.readLine())!=null)

{

System.out.println(line);

}

bufr.close();

//键盘的最常用写法

BufferedReader bufr = new BufferedReader(new InputStreamReader(System.in));

BufferedWriter bufw = new BufferedWriter(new OutputStreamWriter(System.out));

String line = null;

while((line=bufr.readLine())!=null)

{

if(line.equals("over"))

break;

bufw.write(line);

bufw.newLine();

bufw.flush();

}

bufw.flush();

bufr.close();

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