counterbean.java

jsp数据库编程入门

package test;
import java.io.*;

public class counterbean 
{
    private String currentCount = null;//保存文本的变量
    private BufferedReader file; //BufferedReader对象，用于读取文件数据
    private String path;//文件完整路径名
    public counterbean() 
    {
    }
    //ReadFile方法用来读取文件filePath中的数据，并返回这个数据
    public String ReadCounter(String filePath) throws FileNotFoundException
    {
       path = filePath;
       //创建新的BufferedReader对象
       file = new BufferedReader(new FileReader(path));
       String returnStr =null;
       try
       {
         //读取一行数据并保存到currentRecord变量中
         currentCount = file.readLine();
       }
       catch (IOException e)
       {
       	 //错误处理
         System.out.println("读取数据错误.");
       }
       if (currentCount == null)  //如果文件为空
           returnStr = "没有任何记录";
       else //文件不为空
          returnStr =currentCount;
       //返回读取文件的数据
       return returnStr;
     }
    //ReadFile方法用来将数据counter+1后写入到文本文件filePath中
    public void WriteCounter(String filePath,String counter) throws FileNotFoundException
    {
       path = filePath;
       //将counter转换为int类型并加一
       int Writestr = Integer.parseInt(counter)+1;
       try {
          //创建PrintWriter对象，用于写入数据到文件中
          PrintWriter pw = new PrintWriter(new FileOutputStream(filePath));
          //用文本格式打印整数Writestr
          pw.println(Writestr);
          //清除PrintWriter对象
          pw.close();
       } catch(IOException e) 
       {
          System.out.println("写入文件错误"+e.getMessage());
       }
    } 

}