IO流的补充: 字符流FileReader 和FileWriter BufferedReader和BufferedWriter的用法
2013-08-29 19:23
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上次只写了字节流的操作,现在吧字符流的也补上
同样FileReader和BuuferedReader是读取文件到内存,是属于输入流
FileWriter和BufferedWriter是从内存输出到文件中,属于输出流(都是以内存为参照)
看下FileWriter和FileReader的用法
看下BufferedReader和BufferedWriter的用法
同样FileReader和BuuferedReader是读取文件到内存,是属于输入流
FileWriter和BufferedWriter是从内存输出到文件中,属于输出流(都是以内存为参照)
看下FileWriter和FileReader的用法
import java.io.*;; /**演示文件字符流 * * @author Wang Yanming * */ public class Demo1 { public static void main(String[] args) { //文件取出字符流对象(输入流) FileReader fr = null; //写入到文件(输出流) FileWriter fw = null; try { //创建一个file对象 fr = new FileReader("c:\\test.txt"); fw = new FileWriter("d:\\vvv.txt"); //读入到内存 char []c= new char[1024]; int n = 0;//记录实际读取的字符数 while((n=fr.read(c))!=-1) { // System.out.println(c); /*这样又可以打印出来,但是有的情况下会乱码, * 因为c的大小事1024,如果不到1024就打印,会把后面的也打印出来*/ String s = new String(c,0,n);//采用这种形式 System.out.print(s);//这里不要写换行println // fw.write(c); /*当然这样写会把不到1024的那部分数据也写进去 会导致在记事本中乱码,所以建议按下面写*/ fw.write(c, 0, n); } } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } finally { try { fr.close();//如果不关闭会导致文件写不进去 fw.close(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } } } }
看下BufferedReader和BufferedWriter的用法
import java.io.*; /**演示缓冲字符流案例 * BufferedReader 和BufferdWriter * @author Wang Yanming * */ public class Demo1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub BufferedReader br = null; BufferedWriter bw = null; try { // br = new BufferedReader("c:\\test.txt"); //直接诶按照上面写会出错,因为BufferdReader只认识Reader, //而FileReader又是reader的子类先创建一个FileReader对象, FileReader fr = new FileReader("c:\\test.txt");//问题:读取d:\\ss.txt,不能输出可以写 FileWriter fw = new FileWriter("d:\\好似.txt"); br = new BufferedReader(fr); bw = new BufferedWriter(fw); String s=""; while((s=br.readLine())!=null) { System.out.println(s); //这里要写println 因为是按照行读取,不会读换行符,可因参照API, //所以如果不写ln的话就不会换行 /**以下是输出到磁盘**/ s = s+"\r\n";//因为本身是换行的 ,所以要加上"\r\n" bw.write(s); } } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } finally { try { br.close(); bw.close(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } }
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