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();