输入输出流

流的分类：

按数据方向分：输入流和输出流

输入流：InputStream/Reader

输出流：OutputStream/Writer

按数据类型分：

字节流：InputStream/OutputStream

字符流：Reader/Writer

流的选择：在处理纯文本文件时，优先考虑使用字符流，除此之外都使用字节流

原因是：硬盘上的所有文件都是以字节的形式进行传输或者保存的，包括图片等内容，

但字符只是在内存中才会形成的，所以开发中，字节流使用广泛

文件的对拷（字节流）如下:

package com.lovo.io;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;public class TestIoByte {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubFileOutputStream fos = null;//选择流FileInputStream fis = null;try {//操作流fis = new FileInputStream("C:" + File.separator +"222.jpg");//将C:下的文件读入程序fos = new FileOutputStream("G:" + File.separator+"111.jpg");//将程序中文件读出到G：byte[] buffer = new byte[1024];int length = 0;while((length = fis.read(buffer))!= -1){//读文件fos.write(buffer,0,length);//写文件fos.flush();//冲刷，即读进来多少就写出去多少}} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}finally{if(fos!= null){try {fos.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}if(fis!=null){try {fis.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}}}

文件的传输(字符流)如下:

package com.lovo.io;import java.io.File;import java.io.FileNotFoundException;import java.io.FileReader;import java.io.FileWriter;import java.io.IOException;

public class TestIoChar {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubFileWriter fw = null;FileReader fr = null;try {fr = new FileReader("C:"+File.separator+"5-19.txt");fw = new FileWriter("G:"+File.separator+"am.txt");char[] buff = new char[1024];int length = 0;while((length = fr.read(buff))!=-1){fw.write(buff,0,length);fw.flush();}} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}finally{if(fw!=null){try {fw.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}if(fr!=null){try {fr.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}}}

对象的序列化与反序列化如下：

package com.lovo.io;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.ObjectInputStream;import java.io.ObjectOutputStream;import java.io.Serializable;public class  TestIoObject implements Serializable{private String name;private int age;private String ades;public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getAdes() {return ades;}public void setAdes(String ades) {this.ades = ades;}public TestIoObject(String name, int age, String ades) {super();this.name = name;this.age = age;this.ades = ades;}@Overridepublic String toString() {return "姓名:" + name +"\n "+"年龄:" + age+"\n" + "地址:" + ades+ "\n";}/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubTestIoObject tj = new TestIoObject("meimei",15,"石林");/*** * 对象序列化的类， 必须实现Serializable接口  即   implements Serializable  */ObjectOutputStream oos = null;//选择流FileOutputStream fo = null;try {fo = new FileOutputStream("man.txt");//操作流oos = new ObjectOutputStream(fo);oos.writeObject(tj);//对象序列化，将对象以二进制流的方式写到文件} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}finally{if(oos!=null){try {oos.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}if(fo!=null){try {fo.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}/* * 对象的反序列化 */FileInputStream fi = null;ObjectInputStream ois = null;try {fi = new FileInputStream("man.txt");//选择流，从文件中把二进制流转换成对象ois = new ObjectInputStream(fi);tj=(TestIoObject) ois.readObject();//反序列化} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (ClassNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();}finally{if(ois!=null){try {ois.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}if(fi!=null){try {fi.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}System.out.println(tj.toString());//System.out.println(tj.getName()+"\n"+tj.getAge()+"\n"+tj.getAdes());}}