Java IO流操作 (II)

缓冲流 

/*
 * BufferedWriter:将文本写入字符输出流，缓冲各个字符，从而提供单个字符、数组和字符串的高效写入。 
 * BufferedReader:从字符输入流中读取文本，缓冲各个字符，从而实现字符、数组和行的高效读取。
 */
public class BufferedStreamDemo {
	public static void main(String[] args) throws IOException {
		//创建输出缓冲流对象
		/*
		BufferedWriter bw = new BufferedWriter(new FileWriter("bw.txt"));
		bw.write("hello");
		//bw.flush();
		bw.close();
		*/
		
		//创建输入缓冲流对象
		BufferedReader br = new BufferedReader(new FileReader("FileWriterDemo.java"));
		
		/*
		//一次读写一个字符
		int ch;
		while((ch=br.read())!=-1){
			System.out.print((char)ch);
		}
		*/
		
		//一次读写一个字符数组
		char[] chs = new char[1024];
		int len;
		while((len=br.read(chs))!=-1) {
			System.out.print(new String(chs,0,len));
		}
		
		//释放资源
		br.close();
		
	}
}

 

 

缓冲流的特殊功能

 

/*
 * 缓冲流的特殊功能：
 * BufferedWriter
 * 		void newLine():写一个换行符，这个换行符由系统决定
 * BufferedReader
 * 		String readLine():一次读取一行数据，但是不读取换行符
 */
public class BufferedStreamDemo {
	public static void main(String[] args) throws IOException {
		/*
		BufferedWriter bw = new BufferedWriter(new FileWriter("bw2.txt"));
		for(int x=0; x<10; x++) {
			bw.write("hello"+x);
			//bw.write("\r\n");
			bw.newLine();
			bw.flush();
		}
		bw.close();
		*/
		
		BufferedReader br = new BufferedReader(new FileReader("br.txt"));
		
		String line;
		//1:br.readLine()
		//2:line=br.readLine()
		//3:line != null
		while((line=br.readLine())!=null) {
			System.out.println(line);
		}
		
		br.close();
	}
}