【Java】字节流

InputStream?

package java_IO;

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

public class Test_FileInputStream {

	public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
		
		//不能避免汉字出现乱码的问题；
		
		//创建文件字节输入流管道、与源文件接通；
		InputStream is = new FileInputStream(("src\\111.txt"));
		
		//开始读取文件的字节数据；
		//public int read();每次读取一个字节返回，如果没有数据了，返回-1;
		
//		int b1 = is.read();
//		System.out.println((char)b1);
//		int b2 = is.read();
//		System.out.println((char)b2);
//		int b3 = is.read();
//		System.out.println(b3);
		
		int b;
		while((b=is.read())!=-1) {
			System.out.print((char)b);
		}
		is.close();
		System.out.println();
		System.out.println("-------每次读取多个字节------");
		
		//创建一个字节输入流对象代表字节输入管道与源文件接通；
		InputStream in = new FileInputStream(("src\\111.txt"));
		//2.开始读取文件中的字节数据，每次读取多个字节；
		byte[] buffer = new byte[3];
		int len = in.read(buffer);
		//读多少，倒多少；
		String rs = new String(buffer,0,len);
		System.out.println(rs);
		System.out.println("当次读取的字节数量："+len);
		
		//buffer
		int len2 = in.read(buffer);
		//读多少，倒多少；
		String rs2 = new String(buffer,0,len2);
		System.out.println(rs2);
		System.out.println("当次读取的字节数量："+len2);
		in.close();

	}

}

package java_IO;

import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;

public class Test_FileInputStream1 {

	public static void main(String[] args) throws Exception {
		// TODO Auto-generated method stub
		//1.创建一个字节输入流管道与源文件接通；
		InputStream is = new FileInputStream("src\\222.txt");
		
		//2.准备一个字节数组，大小与文件的大小正好一样大；
		File f = new File("src\\222.txt");
		long size = f.length();
		
		byte[] buffer = new byte[(int)size];
		
		int len = is.read(buffer);
		
		System.out.println(new String(buffer));
		
		System.out.println(size);
		System.out.println(len);
		
		is.close();

	}

}

OutputStream

package java_IO;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.OutputStream;

public class Test_FileOutputStream {

	public static void main(String[] args) throws Exception {
		// TODO Auto-generated method stub
		//会覆盖之前的数据；
		OutputStream os = new FileOutputStream("src\\444.txt");
		
		byte[] bytes = "我爱你中国123abs".getBytes();
		os.write(bytes);
		os.write(bytes, 0, 15);
		os.close();
		
		//不会覆盖
		OutputStream os1 = new FileOutputStream("src\\555.txt",true);
		
		os1.write(bytes);
		os1.write(bytes, 0, 15);
		//换行
		os1.write("\r\n".getBytes());
		os1.close();

	}

}

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