java--Proreties

Prorerties

/* 
 * Properties,内存与文件信息交互
 * 表示了一个持久的属性集
 * 
 * 构造方法：
 *  Properties()
 * 
 * 
 */


 //简单使用  创建，添加，遍历，
    private static void method() {
        // 创建属性列表对象
        Properties prop = new Properties();
        //添加映射关系
        prop.put("czbk001","zhangs");
        prop.put("czbk002","lis");
        prop.put("czbk003","wangs");
        
        //遍历
        //获取所有的key，根据key获取value
        Set<java.lang.Object> keys = prop.keySet();
        for(java.lang.Object key:keys)
        {
            java.lang.Object value = prop.get(key);
            System.out.println(key+"="+value);
        }
        System.out.println("------");
        Set<Entry<java.lang.Object, java.lang.Object>> entrys = prop.entrySet();
        for(Entry<java.lang.Object, java.lang.Object> entry:entrys)
        {
            java.lang.Object value = entry.getValue();
            java.lang.Object key = entry.getKey();
            System.out.println(key + "=" + value);
        }




//与IO流的结合
//保存到文件（只能接收打印流）
private static void method2() throws FileNotFoundException {
    // void list(PrintWriter out)
    // void list(PrintStream out)
    //创建属性列表
    Properties prop = new Properties();
    //添加映射关系
    prop.setProperty("CZBK001","zhangs");
    prop.setProperty("CZBK002", "wangs");
    prop.setProperty("CZBK003", "lis");
    
    //创建打印流对象
    PrintWriter out = new PrintWriter("d.txt");
    
    //void list(PrintWriter out)
    prop.list(out);
    //释放资源
    out.close();
}



//从文件读取到prop
private static void method3() throws FileNotFoundException, IOException {
    // void load(Reader reader)
    
    //创建属性列表对象
    Properties prop = new Properties();
    //创建一个输入流对象
    FileReader fr = new FileReader("d.txt");
    
    //void load(Reader reader)
    prop.load(fr);
    
    //释放资源
    fr.close();
    
    System.out.println(prop);
}



//保存到文件(任意)
//void store(Writer writer, String comments)    
private static void method4() throws IOException {
    // 创建属性列表对象
    Properties prop = new Properties();
    // 添加映射关系
    prop.setProperty("CZBK001","zhangs");
    prop.setProperty("CZBK002", "wangs");
    prop.setProperty("CZBK003", "lis");
    // 创建输出流对象
    FileWriter fw = new FileWriter("e.txt");
    
    //void store(Writer writer, String comments)
    prop.store(fw, "comments message");
    
    //释放资源
    fw.close();
}



//编码问题
//如果写入文件时出现了乱码，可以尝试修改编码

OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("b.txt"), "UTF-8");
String s = "你好鸭";
osw.write(s);
osw.close();