Java IO系统--字符流

字符流：尽管字节流提供了处理任何类型输入/输出操作的足够功能，它们补鞥呢直接操作Unicode字符。字符流层次结构的顶层是Reader和Writer抽象类。类似于InputStream和OutputStram

Unicode使用两个字节来表示一个字符，即一个字符占16位

一、Reader的类层次结构

二、Writer的类层次结构

三、Demo

public class StreamTest {

	public static void main(String[] args)  throws Exception{
		FileOutputStream fos = new FileOutputStream("D:/temp/file.txt");

		OutputStreamWriter osw = new OutputStreamWriter(fos);

		BufferedWriter bw = new BufferedWriter(osw);

		bw.write("http://www.baidu.com");
		bw.newLine();
		bw.write("http://www.googlo.com");
		bw.close();

		FileInputStream fis = new FileInputStream("D:/temp/file.txt");

		InputStreamReader isr = new InputStreamReader(fis);

		BufferedReader br = new BufferedReader(isr);

		String str = null;
		while ((str = br.readLine() ) != null) {
			System.out.println(str);

		}

		br.close();

	}
}

　　文本的内容

打印出的输出

四、Demo2 标准输入设备

//标准输入设备
public class StreamTest2 {

	public static void main(String[] args)  throws Exception{
		InputStreamReader isr  = new InputStreamReader(System.in);
		BufferedReader br = new BufferedReader(isr);
		String str ;
		while (null != (str = br.readLine())) {
			System.out.println(str);

		}
		br.close();

	}
}

　　显示效果

五、FileReader使用，

从一个文件逐行读取帮把它输出到标准输出流。

public class FileReader1 {

	public static void main(String[] args) throws Exception{
		FileReader fr = new FileReader("D:/temp/hello.txt");
		BufferedReader br = new BufferedReader(fr);
		String str ;
		while((str = br.readLine()) != null ){
			System.out.println(str);
		}
		br.close();

	}
}

　　

FileWriter使用

public class FileWriter1 {
	public static void main(String[] args) throws Exception {

		String str = "hello world , Hello world";
		char[] buffer = new char[str.length()];
		 str.getChars(0, str.length(), buffer, 0);

		FileWriter fw = new FileWriter("D:/temp/fileWrite.txt");
		BufferedWriter bw = new BufferedWriter(fw);
		for(int i = 0; i < buffer.length ; i++){
			bw.write(buffer[i]);
		}
		bw.close();

	}
}

　　写入结果

六、CharArrayReader使用

public class charArrayReader1 {

	public static void main(String[] args) throws Exception{
		String tmp = "hello world, HI";
		char[] ch = new char[tmp.length()];
	    tmp.getChars(0, tmp.length(), ch, 0);

		CharArrayReader fr = new CharArrayReader(ch);
		BufferedReader br = new BufferedReader(fr);
		String str ;
		while((str = br.readLine()) != null ){
			System.out.println(str);
		}
		br.close();

	}
}