ByteArrayOutputStream和ByteArrayInputStream详解

最新推荐文章于 2025-07-05 10:24:35 发布

caolaosanahnu

最新推荐文章于 2025-07-05 10:24:35 发布

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分类专栏： JAVA 文章标签： string iterator import hashmap byte class

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http://blog.sina.com.cn/s/blog_4c341e2101009f1j.html

ByteArrayOutputStream类是在创建它的实例时，程序内部创建一个byte型别数组的缓冲区，然后利用ByteArrayOutputStream和ByteArrayInputStream的实例向数组中写入或读出byte型数据。在网络传输中我们往往要传输很多变量，我们可以利用ByteArrayOutputStream把所有的变量收集到一起，然后一次性把数据发送出去。具体用法如下:

ByteArrayOutputStream: 可以捕获内存缓冲区的数据，转换成字节数组。

ByteArrayInputStream: 可以将字节数组转化为输入流

import java.io.*;

public class test {
public static void main(String[] args) {
  int a=0;
  int b=1;
  int c=2;
  ByteArrayOutputStream bout = new ByteArrayOutputStream();
  bout.write(a);
  bout.write(b);
  bout.write(c);
  byte[] buff = bout.toByteArray();
  for(int i=0; i<buff.length; i++)
   System.out.println(buff[i]);
  System.out.println("***********************");
  ByteArrayInputStream bin = new ByteArrayInputStream(buff);
  while((b=bin.read())!=-1) {
   System.out.println(b);
  }
}
}

如上所示,ByteArrayOutputStream把内存中的数据读到字节数组中,而ByteArrayInputStream又把字节数组中的字节以流的形式读出,实现了对同一个字节数组的操作.

综合DataOutputStream&DataInputStream的作用和功能,与ByteArrayOutputStream和ByteArrayInputSream使用将更方便.此时DataOutputStream&DataInputStream封闭了字节流,以适当的形式读出了字节数组中的数据.如下所示:

import java.io.*;

public class test {
public static void main(String[] args)throws IOException {
  ByteArrayOutputStream bout = new ByteArrayOutputStream();
  DataOutputStream dout = new DataOutputStream(bout);
  String name = "xxy";
  int age = 84;
  dout.writeUTF(name);
  dout.writeInt(age);
  byte[] buff = bout.toByteArray();
  ByteArrayInputStream bin = new ByteArrayInputStream(buff);
  DataInputStream dis = new DataInputStream(bin);
  String newName = dis.readUTF();
  int newAge = dis.readInt();
  System.out.println(newName+":"+newAge);
}
}

==========

http://blog.sina.com.cn/s/blog_4fb27fd80100obuc.html

ByteArrayOutputStream 类使用实例

(2011-01-01 18:36:27)

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标签：

`02`	`import` `java.io.*;`

03

`04`	`public` `class` `Person` `implements` `Serializable, ObjectInputValidation {`

05

`06`	`static` `Map thePeople =` `new` `HashMap();`

07

`08`	`private` `String name;`

`09`	`private` `String ss;`

10

`11`	`public` `Person(String name, String ss) {`

`12`	`this.name = name;`

`13`	`this.ss = ss;`

`14`	`thePeople.put(ss, name);`

15 }

16

`17`	`private` `void` `readObject(ObjectInputStream in)`

`18`	`throws` `IOException, ClassNotFoundException {`

`19`	`in.registerValidation(this,` `5);`

`20`	`in.defaultReadObject();`

21 }

22

`23`	`public` `void` `validateObject()` `throws` `InvalidObjectException {`

`24`	`if` `(thePeople.containsKey(this.ss)) {`

`25`	`throw` `new` `InvalidObjectException(this.name +` `" already exists");`

26 }

`27`	`else` `{`

`28`	`thePeople.put(this.ss,` `this.name);`

29 }

30 }

31

`32`	`public` `String toString() {`

`33`	`return` `this.name +` `"\t"` `+` `this.ss;`

34 }

35

`36`	`public` `static` `void` `main(String[] args)`

`37`	`throws` `IOException, ClassNotFoundException {`

38

`39`	`Person p1 =` `new` `Person("Rusty",` `"123-45-5678");`

`40`	`Person p2 =` `new` `Person("Beth",` `"321-45-5678");`

`41`	`Person p3 =` `new` `Person("David",` `"453-45-5678");`

`42`	`Person p4 =` `new` `Person("David",` `"453-45-5678");`

43

`44`	`Iterator iterator = thePeople.values().iterator();`

`45`	`while` `(iterator.hasNext()) {`

`46`	`System.out.println(iterator.next());`

47 }

48

`49`	`ByteArrayOutputStream bout =` `new` `ByteArrayOutputStream();`

`50`	`ObjectOutputStream oout =` `new` `ObjectOutputStream(bout);`

`51`	`oout.writeObject(p1);`

`52`	`oout.writeObject(p2);`

`53`	`oout.writeObject(p3);`

`54`	`oout.writeObject(p4);`

`55`	`oout.flush();`

`56`	`oout.close();`

57

`58`	`ByteArrayInputStream bin =` `new` `ByteArrayInputStream(bout.toByteArray());`

`59`	`ObjectInputStream oin =` `new` `ObjectInputStream(bin);`

60 try {

`61`	`System.out.println(oin.readObject());`

`62`	`System.out.println(oin.readObject());`

`63`	`System.out.println(oin.readObject());`

`64`	`System.out.println(oin.readObject());`

65 }

`66`	`catch` `(InvalidObjectException ex) {`

`67`	`System.err.println(ex);`

68 }

`69`	`oin.close();`

70

`71`	`// now empty the map and try again`

`72`	`thePeople.clear();`

`73`	`bin =` `new` `ByteArrayInputStream(bout.toByteArray());`

`74`	`oin =` `new` `ObjectInputStream(bin);`

75 try {

`76`	`System.out.println(oin.readObject());`

`77`	`System.out.println(oin.readObject());`

`78`	`System.out.println(oin.readObject());`

`79`	`System.out.println(oin.readObject());`

80 }

`81`	`catch` `(InvalidObjectException ex) {`

`82`	`System.err.println(ex);`

83 }

`84`	`oin.close();`

85

`86`	`iterator = thePeople.values().iterator();`

`87`	`while` `(iterator.hasNext()) {`

`88`	`System.out.println(iterator.next());`

89 }

90 }

91 }

import java.util.*;

`02`	`import` `java.io.*;`