properties取值

Class.forName(classPath).newInstance() 时也要注意此问题的产生

错误代码：

private String getDb() {
    Properties pro = new Properties(); 
    String resourcePath = "config.properties"; 
    try { 
        pro.load( 
            this.getClass(). 
            getClassLoader(). 
            getResourceAsStream(resourcePath) 
        ); 
        db = pro.getProperty("db"); 
    } catch (IOException e) { 
        e.printStackTrace(); 
    } 
    return db;
}

问题：db为null

分析：java程序默认是在根路径 src下查找，所以要指定路径

解决：

private String getDb() {
    Properties pro = new Properties(); 
    String resourcePath = "com/bigtalk/patterns/abstractFactory/config.properties"; 
    try { 
        pro.load( 
            this.getClass(). 
            getClassLoader(). 
            getResourceAsStream(resourcePath) 
        ); 
        db = pro.getProperty("db"); 
    } catch (IOException e) { 
        e.printStackTrace(); 
    } 
    return db;
}