java对properties文件的操作

在做程序时，往往会有一些固定的或长期的值，这些值或许在将来才会被更改。

    由于程序完成时，把这些值写在代码，将来更改起不方便。（而且容易忘记在代码中什么地方，哪个文件中时）所以，我们建议将这些值写入配置文件中。

    今天就让我们一起来看看，在 JAVA 中对 properties 这种配置文件的操作吧。

1、properties 文件

#ParseZUrlNum.properties
#Tue Nov 15 11:52:15 CST 2005
nextnum=360
firstnum=73
secondnum=72

<script type="text/javascript"></script> <script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js"> </script>

2、读写文件

{

ParseNZ pnz = new ParseNZ();

Properties properties = new Properties();

try {

            File f = new File("ParseZUrlNum.properties");
            properties = pnz.getProperties ("e:/work/product/src/com/yesky/productattribute/p/z/model/ParseZUrlNum.properties");
} catch (Exception e) {
            e.printStackTrace();
}
String firstnum = properties.getProperty("firstnum");
String secondnum = properties.getProperty("secondnum");
String nextnum = properties.getProperty("nextnum");

int first=Integer.parseInt(firstnum);
int second=Integer.parseInt(secondnum);
int next=Integer.parseInt(nextnum);

System.out.println("firstnum=" + firstnum);
System.out.println("secondnum=" + secondnum);
System.out.println("nextnum=" + nextnum);

pnz.setProperties(first,second,next);

}

 

3、ParseNZ 类

public class ParseNZ{
    Properties p = new Properties();

    public Properties getProperties(String filename) throws IOException {

        ClassLoader cl = this.getClass().getClassLoader();
        FileInputStream input;
        // if(cl!=null)
        //input=cl.getResourceAsStream(filename);
        input = new FileInputStream(filename);
        //else
        //input=ClassLoader.getSystemResourceAsStream(filename);

        p.load(input);
        return p;

    }

   

    public void setProperties(int first, int second, int next) {
        p.setProperty("firstnum",String.valueOf(first));
        p.setProperty("secondnum",String.valueOf(second));
        p.setProperty("nextnum",String.valueOf(next));

        File file = new File ("e:/work/product/src/com/yesky/productattribute/p/z/model/ParseZUrlNum.properties");
        try {
              OutputStream fos = new FileOutputStream(file);
              p.store(fos, "ParseZUrlNum.properties");
              fos.close();
        } catch (FileNotFoundException ex) {
            System.out.println("file is NULL !!!");
              ex.printStackTrace();
        } catch (IOException ex) {
            System.out.println("IO is Error !!!");
              ex.printStackTrace();
        }
    }

}

    本例中地址是写死的。可改为如： File file = new File(System.getProperty("user.dir")
                                 + "/EMweb/WEB-INF/admininfo.properties");

这里面的关键是System.getProperty("user.dir") 返回当前工作目录。