java中的io流，对于字节和字符的读写操作（基础）

1.字节的输入流和输出流

输入流 FileInputStream（即将记事本的字节读取出来）

package wjq;
//字节流的输入 fileInputStream
import java.io.FileInputStream;
import java.io.IOException;

public class Example01{
	public static void main(String[] args) throws IOException {
		FileInputStream in = new FileInputStream("c:\\java\\Example\\hh.txt");
		int b = 0;
		System.out.println("你文件的字节是");
		while((b=in.read())!=-1) { //等于-1表示文件的字节读完了
			System.out.println(b);
		}
		in.close();
	}
}

ASCII编码表

首先在自己的c盘上创建一个文本文档，并写入一单词（如下）

运行结果

注：h对应ASCII编码中的104，其它的都是表中的对应关系

输出流 FileOutoutStream

package wjq;
//字节的输出 FileOutputStream
import java.io.FileOutputStream;
import java.io.IOException;

public class Example02{
	public static void main(String[] args) throws IOException {
		FileOutputStream out = new FileOutputStream("c:\\java\\Example\\rr.txt");
		String str ="good";
		out.write(str.getBytes());
		out.close();
	}
}

将good写入到文档中

3.文件的逐个拷贝

package wjq;
//文件的拷贝 逐个拷贝
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class Example03{
	public static void main(String[] args) throws IOException {
		FileInputStream in = new FileInputStream("c:\\java\\Example\\hh.txt");
		FileOutputStream out = new FileOutputStream("c:\\java\\Example\\jj.txt");
		int b = 0;
		long beginTime = System.currentTimeMillis();
		while((b=in.read())!=-1){
			out.write(b);
		}
		long endTime = System.currentTimeMillis();
		System.out.println("拷贝用的时间为"+(endTime-beginTime)+"毫秒");
		in.close();
		out.close();
	}
}

4.使用字节缓冲区拷贝文件

package wjq;
//使用字节缓冲区拷贝文件
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class Example04 {
	public static void main(String[] args) throws IOException  {
		FileInputStream in = new FileInputStream("c:\\java\\Example\\hh.txt");		
		FileOutputStream out = new FileOutputStream("c:\\java\\Example\\n.txt");
		int b= 0;
		byte[] buff = new byte[1024];
		long beginTime = System.currentTimeMillis();
		while((b=in.read(buff))!=-1) {
			out.write(buff,0,b);
		}
		long endTime = System.currentTimeMillis();
		System.out.println("拷贝文件所用的时间为"+(endTime-beginTime)+"毫秒");
		in.close();
		out.close();
	}
}

5.使用字节缓冲流拷贝文件

package wjq;
//使用字节缓冲流拷贝文件
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class EXample05 {
	public static void main(String[] args) throws IOException {
		BufferedInputStream bu = new BufferedInputStream
				(new FileInputStream("c:\\java\\Example\\hh.txt"));
		BufferedOutputStream bk = new BufferedOutputStream
			   (new FileOutputStream("c:\\java\\Example\\ggg.txt"));
		int b = 0;
		long beginTime = System.currentTimeMillis();
		while((b=bu.read())!=-1) {
			bk.write(b);
		}
		long endTime = System.currentTimeMillis();
		System.out.println(endTime-beginTime);
		bu.close();
		bk.close();
	}
}

2.字符流

package wjq1;
//字符流操作文件，从文件中逐个读取字符
import java.io.FileReader;
import java.io.IOException;

public class Example01{
	public static void main(String[] args) throws IOException {
		FileReader fileReader = new FileReader("c:\\java\\Example\\hh.txt");
		int b =0;
		while((b=fileReader.read())!=-1) {
			System.out.print((char)b);
		}
		fileReader.close();		
	}
} 

package wjq1;
//字符流逐个写字符
import java.io.FileWriter;
import java.io.IOException;

public class Example02 {
	public static void main(String[] args) throws IOException {
		FileWriter h = new FileWriter("c:\\java\\Example\\ffff.txt");
		h.write("一个人玩,\t\n");
		h.write("没有人一起玩,\t\n");
		h.write("好多人一起玩,\t\n");
		h.write("都在玩,\t\n");
		h.close();
	}
}

package wjq1;
//使用字符缓冲区拷贝文件
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class Example03 {
	public static void main(String[] args) throws IOException {
		FileReader gg = new FileReader("C:\\java\\Example\\ffff.txt");
		FileWriter ww = new FileWriter("c:\\java\\Example\\vvvvvv.txt");
		int b = 0;
		char[] buff = new char[1024];
		while((b=gg.read(buff))!=-1) {
			ww.write(buff,0,b);
		}
		gg.close();
		ww.close();
	}
}

package wjq1;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

//使用字符缓冲流拷贝文件
public class EXample04 {
	public static void main(String[] args) throws IOException {
		BufferedReader bb = new BufferedReader(new FileReader
				("C:\\java\\Example\\ffff.txt"));
		BufferedWriter hh = new BufferedWriter(new FileWriter
				("c:\\java\\EXample\\khjh.txt"));
		String str = null;
		while((str = bb.readLine())!=null) {
		    hh.write(str);
		    hh.newLine();
		}
		bb.close();
		hh.close();
		
	}
}