演示java程序中的数据如何与磁盘中的TXT文档进行数据操作

package streamDemo;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class StreamDemo {
    public static void main(String[] args) throws IOException {
        /*
         * 下面演示java中的数据如何写入磁盘中的A.txt文档中
         */
        
        // 节点流FileOutputStream直接以A.txt作为数据源操作 OutputStream
        OutputStream fileOutputStream = new FileOutputStream("A.txt");

        // 过滤流BufferedOutputStream进一步装饰节点流，提供缓冲写
        OutputStream bufferedOutputStream = new BufferedOutputStream(fileOutputStream);
        // 过滤流DataOutputStream进一步装饰过滤流，使其提供基本数据类型的写
        DataOutputStream out = new DataOutputStream(bufferedOutputStream);

        out.writeChars("I love China,I am Chinese.I hate Japan" + "I love China,I am Chinese.I hate Japan");

        out.flush();
        out.close();
        // 此处输入节点流，过滤流正好跟上边输出对应，读者可举一反三
        InputStream fileInputputStream = new FileInputStream("A.txt");

        InputStream bufferedInputputStream = new BufferedInputStream(fileInputputStream);

        DataInputStream in_0 = new DataInputStream(bufferedInputputStream);

        in_0.close();

        /*
         * 从磁盘的B.txt文档中读入数据到java程序中
         */
        
        InputStream fileInputStream = new FileInputStream("B.txt");

        InputStream bufferedInputStream = new BufferedInputStream(fileInputStream);

        DataInputStream in_1 = new DataInputStream(bufferedInputStream);
        
        System.out.print(in_1.readLine());

    }
}