java io实例具体解释-白红宇

java io实例具体解释

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发布时间：2019-05-09

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import java.io.BufferedReader;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.DataOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.FileWriter;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.io.OutputStream;

import java.io.PipedInputStream;

import java.io.PipedOutputStream;

import java.io.PrintStream;

import java.io.PushbackInputStream;

import java.io.RandomAccessFile;

import java.io.SequenceInputStream;

import java.io.Serializable;

import java.io.Writer;

import java.util.zip.ZipEntry;

import java.util.zip.ZipException;

import java.util.zip.ZipFile;

import java.util.zip.ZipOutputStream;

import org.junit.Before;

import org.junit.Test;

/**

* 流操作

* @author Administrator

public class FileOpera {

//String path="";

String str="";

@Before

public void init(){

//path="d:"+File.separator+"test";

str="d:"+File.separator+"test"+File.separator+"test.txt";

}

/*使用RandomAccessFile写入文件*/

@Test

public void testAccess() throws IOException{

init();

File file=new File(str);

RandomAccessFile f=new RandomAccessFile(file,"rw");

f.writeBytes("abcdef");

f.writeInt(21);

f.writeDouble(32.11);

f.close(); //会乱码

}

/*字节流输出到文件OutputStream InputputStream*/

@Test

public void testByte1() throws IOException{

init();

File file =new File(str);

//OutputStream out=new FileOutputStream(file);

OutputStream out=new FileOutputStream(file,true);

String s="总共多少人";

out.write(s.getBytes());//按字节

out.flush();

out.close();

}

/*字符流输出到文件 Reader(读) Writer(写)*/

@Test

public void testReader() throws IOException{

init();

File file=new File(str);

Writer writer=new FileWriter(file,true);

//Writer writer=new OutputStreamWriter(new FileOutputStream(file));//将字节输出流转换为字符输出流

writer.write("你好世界");

writer.flush();

writer.close();

}

/*内存字节流-------------使用内存操作流（字节方式）ByteArrayInputStream ByteArrayOutputStream*/

@Test

public void testByte() throws IOException{

String str="ROLLENHOLT";

ByteArrayInputStream input=new ByteArrayInputStream(str.getBytes());//以字节数组方式读入缓存区

ByteArrayOutputStream output=new ByteArrayOutputStream();

int temp=0;

while((temp=input.read())!=-1){

char ch=(char)temp;

output.write(Character.toLowerCase(ch));

}

String outStr=output.toString();

input.close();

output.close();

System.out.println(outStr);

}

/*字节管道流主要是进行两个线程之间的通信 PipedOutputStream PipedInputStream */

@Test

public void testPied(){

Send send=new Send();

Revice recive=new Revice();

try{

//管道连接

send.getOut().connect(recive.getInput());

}catch (Exception e) {

e.printStackTrace();

}

new Thread(send).start();

new Thread(recive).start();

}

class Send implements Runnable{

private PipedOutputStream out=null;

public Send(){

out= new PipedOutputStream();

}

public PipedOutputStream getOut(){

return this.out;

}

@Override

public void run() {

String message="hello 中国";

try{

out.write(message.getBytes());

}catch (Exception e) {

e.printStackTrace();

}try{

out.close();

}catch (Exception e) {

e.printStackTrace();

}

class Revice implements Runnable{

private PipedInputStream input=null;

public Revice(){

this.input=new PipedInputStream();

}

public PipedInputStream getInput(){

return this.input;

}

public void run(){

byte[] b=new byte[1000];

int len=0;

try{

len=this.input.read(b);

}catch (Exception e) {

e.printStackTrace();

}try{

input.close();

}catch (Exception e) {

e.printStackTrace();

}

System.out.println("接受的内容为 "+(new String(b,0,len)));

}

/*打印流 PrintStream*/

@Test

public void testPrint() throws FileNotFoundException{

init();

File file=new File(str);

PrintStream print=new PrintStream(new FileOutputStream(file,true));

print.print("爱我中华");

print.flush();

print.close();

}

/*输出到屏幕上*/

@Test

public void testSreen(){

OutputStream out=System.out;

try{

out.write("hello".getBytes());

}catch (Exception e) {

e.printStackTrace();

}

try{

out.close();

}catch (Exception e) {

e.printStackTrace();

}

/*输入输出重定向*/

@Test

public void testRedirect(){

// 此刻直接输出到屏幕

System.out.println("hello");

init();

File file = new File(str);

try{

System.setOut(new PrintStream(new FileOutputStream(file,true)));

}catch(FileNotFoundException e){

e.printStackTrace();

}

System.out.println("这些内容在文件里才干看到哦！");

//重定向err输出

System.err.println("这些在控制台输出");

try{

System.setErr(new PrintStream(new FileOutputStream(file,true)));

}catch(FileNotFoundException e){

e.printStackTrace();

}

System.err.println("这些在文件里才干看到哦！

");

}

/*BufferedReader仅仅能接受字符流的缓冲区。由于每个中文须要占领两个字节，所以须要将System.in这个字节输入流变为字符输入流，採用*/

@Test

public void testBuffer(){

BufferedReader buf = new BufferedReader(new InputStreamReader(System.in));//将字节流转化为字符流

String str = null;

System.out.println("请输入内容");

try{

str = buf.readLine();

}catch(IOException e){

e.printStackTrace();

}

System.out.println("你输入的内容是：" + str);

}

/*数据操作流DataOutputStream、DataInputStream类*/

@Test

public void testData() throws IOException{

init();

File file=new File(str);

char[] ch = { 'A', 'B', 'C' };

DataOutputStream out=new DataOutputStream(new FileOutputStream(file,true));

for(char temp : ch){

out.writeChar(temp);

}

out.close();

}

/*合并流 SequenceInputStream*/

@Test

public void testSequence() throws IOException{

File file1 = new File("d:" + File.separator +"test"+File.separator+"test.txt");

File file2 = new File("d:" + File.separator +"test"+File.separator+"hello2.txt");

File file3 = new File("d:" + File.separator +"test"+File.separator+"hello.txt");

if(!file1.exists()){

file1.createNewFile();

}

if(!file2.exists()){

file2.createNewFile();

}

if(!file3.exists()){

file3.createNewFile();

}

InputStream input1 = new FileInputStream(file1);

InputStream input2 = new FileInputStream(file2);

OutputStream output = new FileOutputStream(file3);

// 合并流

SequenceInputStream sis = new SequenceInputStream(input1, input2);

int temp = 0;

while((temp = sis.read()) != -1){

output.write(temp);

}

input1.close();

input2.close();

output.close();

sis.close();

}

/*文件压缩 ZipOutputStream类*/

@Test

public void testZip() throws IOException{

init();

File file=new File(str);

String path="d:"+File.separator+"test"+File.separator+"test.zip";

File zipFile=new File(path);

InputStream in=new FileInputStream(file);

ZipOutputStream zip=new ZipOutputStream(new FileOutputStream(zipFile));

zip.putNextEntry(new ZipEntry(file.getName()));

// 设置凝视

zip.setComment("hello");

int temp = 0;

while((temp = in.read()) != -1){

zip.write(temp);

}

in.close();

zip.close();

}

/*解压缩ZipFile类*/

@Test

public void testZipFile() throws ZipException, IOException{

init();

String str="d:"+File.separator+"test"+File.separator+"test.zip";

String path="d:"+File.separator+"test"+File.separator+"zip.txt";

File file=new File(str);

File zipf=new File(path);

ZipFile zipFile = new ZipFile(file);

System.out.println("压缩文件的名称为：" + zipFile.getName());

ZipEntry entry = zipFile.getEntry("test.txt");

InputStream input = zipFile.getInputStream(entry);

OutputStream output = new FileOutputStream(zipf);

int temp = 0;

while((temp = input.read()) != -1){

output.write(temp);

}

input.close();

output.close();

}

/*PushBackInputStream回退流*/

@Test

public void testPush() throws IOException{

String str = "hello,rollenholt";

PushbackInputStream push = null;

ByteArrayInputStream bat = null;

bat = new ByteArrayInputStream(str.getBytes());

push = new PushbackInputStream(bat);

int temp = 0;

while((temp = push.read()) != -1){

if(temp == ','){

push.unread(temp);

temp = push.read();

System.out.print("(回退" + (char) temp + ") ");

}else{

System.out.print((char) temp);

}

/*System 类的一些操作*/

@Test

public void testSys(){

System.out.println("系统默认编码为：" + System.getProperty("file.encoding"));

}

/**

* 将一个对象流化即实现Serializable接口（默认将所有属性序列化）还能够实现一组对象的序列化

* 假设不想所有属性被实例化能够在实体中使用如private transient String name; transient属性

* 能够在对象输入（ObjectInputStream）输出（ObjectOutputStream）流中直接操作对象

* 实现Externalizable接口。能够将部分属性实例化

* @throws IOException

* @throws ClassNotFoundException

/*ObjectOutputStream*/

@Test

public void testObject() throws IOException, ClassNotFoundException{

init();

File file = new File(str);

ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(file,true));

oos.writeObject(new Person("laoma", 20,"男"));

oos.close();

//查看

ObjectInputStream input = new ObjectInputStream(new FileInputStream(file));

Object obj = input.readObject();

input.close();

System.out.println(obj);

}

/*PushBackInputStream回退流*/

@Test

public void testRect(){

}

參考自：http://www.cnblogs.com/rollenholt/archive/2011/09/11/2173787.html

转载于:https://www.cnblogs.com/ljbguanli/p/7293832.html

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