1. 简介
通过按字节的方式读写文件，实际上是比较底层的，并不算方便。实际程序员可能更喜欢指定编码（如UTF-8），并按字符读写。
Java提供了封装好的阅读器、书写器替我们完成了流-字符转换，我们直接可以操作读写字符的函数即可。
2. 示例
工具类
//工具类 package com.maoge.stream; import java.io.File; public class StreamUtils { //用于定义每次读取的长度 public static final int BUFFER_LENGTH=512; //文件对象 public static File FILE_FOR_READ; public static File FILE_FOR_WRITE; static{ FILE_FOR_READ=new File("C:\\test.txt"); FILE_FOR_WRITE=new File("C:\\result.txt"); } }
阅读器、书写器
package com.maoge.stream; import java.io.BufferedReader; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStreamWriter; //阅读器、书写器示例 public class ReaderWriterDemo { //测试入口 public static void main(String[] args){ //书写器OutputStreamWriter示例 writeText("哈利路亚"); //阅读器InputStreamReader示例 readText(); //可以在InputStreamReader上再串联一个BufferedReader，实现按行读取，这个就非常方便了。 System.out.println("开始按行读取"); readLine(); } public static void writeText(String text){ OutputStreamWriter out=null; try { //OutputStreamWriter是按字符（非字节了）方式写入，同时可以指定编码 out=new OutputStreamWriter(new FileOutputStream(StreamUtils.FILE_FOR_WRITE),"UTF-8"); out.write(text); out.flush(); } catch (Exception e) { System.out.println(e.toString()); }finally{ try { out.close(); } catch (IOException e) { System.out.println(e.toString()); } } } public static void readText(){ InputStreamReader in=null; try{ //注意阅读器一次读取一个字符 in=new InputStreamReader(new FileInputStream(StreamUtils.FILE_FOR_READ),"UTF-8"); StringBuilder sb=new StringBuilder(); int readInt; while((readInt=in.read())!=-1) sb.append((char)readInt); System.out.println(sb.toString()); }catch(Exception e){ System.out.println(e.toString()); }finally{ try { in.close(); } catch (IOException e) { System.out.println(e.toString()); } } } public static void readLine(){ BufferedReader br=null; try{ br=new BufferedReader(new InputStreamReader(new FileInputStream(StreamUtils.FILE_FOR_READ),"UTF-8")); String line = null; while((line = br.readLine())!=null) { System.out.println(line); } }catch(Exception e){ System.out.println(e.toString()); }finally{ try { br.close(); } catch (IOException e) { System.out.println(e.toString()); } } } }
