Java IO学习笔记：字符流

 

字符流的处理和字节流差不多，API基本上完全一样，就是计量单位不同。另外字符流还提供一些其他的处理流，比如按行读取流、字符串流等等。

特别注意，当文件有汉字时，注意编码格式：

//设置流的编码格式，防止乱码
   InputStreamReader isr = new InputStreamReader(
     new FileInputStream("f:/poem.txt"), "gbk");
   BufferedReader fReader = new BufferedReader( isr );

 

下面给个例子看看：

 

import java.io.*; 

/** 
* 字符流测试 
* 
* @author leizhimin 2008-8-27 22:16:44 
*/ 
public class TestIOStream { 
    public static void main(String[] args) { 
        testReaderWriter(); 
        testLineNumberReader(); 
    } 

    /** 
     * 带缓冲的字符流 
     */ 
    public static void testReaderWriter() { 
        int bufsize = 25; 
        try { 
            BufferedReader bufferedReader = new BufferedReader(new FileReader(new File("C:\\x.txt"))); 
            BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(new File("C:\\xb.txt"))); 

            char buf[] = new char[bufsize];     //字符缓冲区 
            while (bufferedReader.read(buf) != -1) { 
                bufferedWriter.write(buf); 
            } 
            bufferedWriter.flush(); 
            bufferedReader.close(); 
            bufferedWriter.close(); 

        } catch (FileNotFoundException e) { 
            e.printStackTrace(); 
        } catch (IOException e) { 
            e.printStackTrace(); 
        } 
    } 

    /** 
     * 按行读取的字符流 
     */ 
    public static void testLineNumberReader() { 
        try { 
            LineNumberReader lineNumberReader = new LineNumberReader(new BufferedReader(new FileReader(new File("C:\\x.txt")))); 

            String lineString;      //行字符串变量 
            int x = 0;              //行号 
            while ((lineString = lineNumberReader.readLine()) != null) { 
                x++; 
                System.out.println("行号：" + x + " >>>" + lineString); 
            } 
            lineNumberReader.close(); 
        } catch (FileNotFoundException e) { 
            e.printStackTrace(); 
        } catch (IOException e) { 
            e.printStackTrace(); 
        } 
    } 
}

 

运行结果：

行号：1 >>>白日依山尽，黄河入海流。  
行号：2 >>>欲穷千里目，更上一层楼。 
行号：3 >>> 
行号：4 >>>—— 王之涣《登鹳雀楼》