马士兵J2SE-第八章-流

访问文件

package com.zzk.test;

import java.io.*;

public class test {
	public static void main(String[] args) {
		int b=0;
		FileInputStream in=null;
		try {
			in=new FileInputStream("D:\\test\\a\\zzk.txt");
		}catch (FileNotFoundException e) {
			System.out.println("找不到指定文件");
			System.exit(-1);
		}

		try {
			long num=0;
			while((b=in.read())!=-1) {
				System.out.print((char)b);
				num++;
			}
			in.close();
			System.out.println();
			System.out.println("共读取了"+num+"个字节");
		}catch(IOException e1) {
			System.out.println("文件读取错误");
			System.exit(-1);
		}
	}
}

输出：

a123123ewawewaq123
asd
ads
adsd
共读取了31个字节

文件复制：

package com.zzk.test;

//文件复制

import java.io.*;
public class test {
	  public static void main(String[] args) {
		  int b = 0;
		  FileInputStream in = null;
		  FileOutputStream out = null;
		  try {
		    in = new FileInputStream("d:/test/a/zzk.txt");
		    out = new FileOutputStream("d:/test/a/zzk1.txt");
		    while((b=in.read())!=-1){
		      out.write(b);
		    }
		    in.close();
		    out.close();
		  } catch (FileNotFoundException e2) {
		    System.out.println("找不到指定文件"); System.exit(-1);
		  } catch (IOException e1) {
		    System.out.println("文件复制错误"); System.exit(-1);
		  }
		  System.out.println("文件已复制");
	  }
	}

import java.io.*;
public class TestFileReader {
  public static void main(String[] args) {
    FileReader fr = null;
    int c = 0;
    try {
      fr = new FileReader("d:\\share\\java\\io\\TestFileReader.java");
      int ln = 0;
      while ((c = fr.read()) != -1) {
        //char ch = (char) fr.read();
        System.out.print((char)c);
        //if (++ln >= 100) { System.out.println(); ln = 0;}
      }
      fr.close();
    } catch (FileNotFoundException e) {
      System.out.println("找不到指定文件");
    } catch (IOException e) {
      System.out.println("文件读取错误");
    }

  }
}

import java.io.*;
public class TestFileWriter {
  public static void main(String[] args) {
    FileWriter fw = null;
    try {
      fw = new FileWriter("d:\\bak\\unicode.dat");
      for(int c=0;c<=50000;c++){
        fw.write(c);
      }
      fw.close();
    } catch (IOException e1) {
    	e1.printStackTrace();
      System.out.println("文件写入错误");
      System.exit(-1);
    }
  }
}