testio.java

一些简单的java程序。老师很认真

package com.test;
import java.io.*;
public class TestIo {
	//从键盘输入字符串
	public String readStringFromConsole()
	{
		try
		  {
			BufferedReader stdin =new BufferedReader(new InputStreamReader(System.in));
			System.out.println("Enter a line:");
			String s=new String();
			s=stdin.readLine();
			System.out.println(s);
			return s;
		  }catch(Exception e){System.out.println("io error");return null;}		
	}

	//从键盘输入整数
	public int readIntFromConsole()
	{return Integer.parseInt(readStringFromConsole());}
	
	//从键盘输入双精度数
    public double readDoubleFromConsole()
    { return Double.parseDouble(readStringFromConsole());}
    
	//从一个文件读取数据
	public String readFromFile(String fileName)
	{
		try
		{
			BufferedReader in =new BufferedReader(new FileReader(fileName));
		    String s,s2 = new String();
		    while((s=in.readLine())!=null)
			s2=s+"\\"; 
		    System.out.println(s2);
			in.close();
			return s2;
		}catch(Exception e){System.out.println("file not found");return null;}
	}
	
	//将字符串信息输出到文件
	public void outputToFile(String s,String fileName){
		try{
		    BufferedReader in4 =new BufferedReader(new StringReader(s)); 
		    PrintWriter out1 =new PrintWriter(new BufferedWriter(new FileWriter(fileName)));
		    int lineCount = 1;
		    while((s = in4.readLine())!=null)
		    	out1.println(lineCount+s);
		    out1.close();
		    in4.close();
		    }catch(EOFException ex){System.out.println("End of stream");}
		    catch(IOException e){e.printStackTrace();}
	}
	
	public static void main(String[] args) throws IOException{
	  String s=new String();
	  TestIo ti=new TestIo();
	  s=ti.readStringFromConsole();
	  System.out.println("@@@@@@@@@@@@@@@@");
	  ti.outputToFile(s,"c:/fileExample1.txt");
	  s=ti.readFromFile("c:/fileExample1.txt");
	}
}