如何改變屬性文件中某一個鍵的值﹖

Question

#test.properties
#Fri Oct 03 15:07:35 CST 2003
fieldC=casdsd
fieldB=bbbbbb
fieldA=aaaaapublic static void main(String[] arg) {
    try {
        FileInputStream fs = new FileInputStream("c:/test.properties");
        Properties p = new Properties();
        p.load(fs);
        System.out.println(p.get("fieldA"));
        System.out.println(p.get("fieldB"));
        System.out.println(p.get("fieldD"));        p.setProperty("fieldA","new aaaa");
        FileOutputStream fo = new FileOutputStream("c:/test.properties");
        p.store(fo,"test.properties");
    }
    catch(Exception e) {
        System.out.println("[Temp].main() eror:" + e);
    }
}