java下properties属性文件操作

package cn.stat.p1.file;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Properties;
import java.util.Set;

public class proc {

    /**
     * @param args
     * @throws IOException
     */
    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub
        //创建文件对像
        File file=new File("info.txt");

        //判断文件是否存在
        if(!file.exists())
        {
            file.createNewFile();
        }
        //创建文件读取对像
        FileReader fr=new FileReader(file);

        //创建属性集合
        Properties pt=new Properties();
        //读取属性集合
        pt.load(fr);

        //输出到控制台
        pt.list(System.out);

        //更改
        pt.setProperty("lisi", "99");
        //创建文件写入对像
        FileWriter fw=new FileWriter(file);
        //将此 Properties 表中的属性列表写入对像
        pt.store(fw,"");

        pt.list(System.out);
        fr.close();

    }

    public static void cl2() throws FileNotFoundException, IOException {
        Properties pt=new Properties();

        FileInputStream fis=new FileInputStream("info.txt");

        pt.load(fis);

        pt.list(System.out);
    }

    public static void cl() throws FileNotFoundException, IOException {
        Properties pt=new Properties();
        pt.setProperty("zhangsan","22");
        pt.setProperty("lisi","332");
        pt.setProperty("xiaoli","452");
        pt.setProperty("nini","112");

        FileOutputStream fos=new FileOutputStream("info.txt");

        pt.store(fos,"names");

        fos.close();

        pt.list(System.out);

        Set<String> st=pt.stringPropertyNames();

        for(String ss : st)
        {
            String value=pt.getProperty(ss);
            System.out.println(ss+" "+value);
        }
    }

}