王中山古筝曲集,we sky,marumaru 日语
1.cglib
beangenerator beangenerator = new beangenerator();
beangenerator.addproperty("id", long.class);
beangenerator.addproperty("username", string.class);
object obj = beangenerator.create();
beanmap beanmap = beanmap.create(obj);
beancopier copier = beancopier.create(user.class, obj.getclass(), false);
user user = new user();
user.setid(1l);
user.setusername("name1");
user.setpassword("123");
copier.copy(user, obj, null);
system.out.println(beanmap.get("username"));class clazz = obj.getclass();
method[] methods = clazz.getdeclaredmethods();for (int i = 0; i < methods.length; i++) {
system.out.println(methods[i].getname());
}
输出结果:
name1
getid
getusername
setid
setusername
从输出结果可以看出最后生成的obj只有id和username两个属性
2.org.apache.commons.beanutils
dynaproperty property = new dynaproperty("id", long.class);
dynaproperty property1 = new dynaproperty("username", string.class);
basicdynaclass basicdynaclass = new basicdynaclass("user", null, newdynaproperty[]{property, property1});
basicdynabean basicdynabean = new basicdynabean(basicdynaclass);
user user = new user();
user.setid(1l);
user.setusername("name1");
user.setpassword("123");
beanutils.copyproperties(basicdynabean, user);map<string, object> map = basicdynabean.getmap();
iterator<string> it = map.keyset().iterator();while (it.hasnext()) { string key = it.next();
system.out.println(key + ":" + map.get(key));
}
输入结果:
id:1username:name1
查看basicdynabean与basicdynaclass之间的关系
dynabean的源码
public interface dynabean {
public boolean contains(string name, string key);
public object get(string name);
public object get(string name, int index);
public object get(string name, string key);
public dynaclass getdynaclass();
public void remove(string name, string key);
public void set(string name, object value);
public void set(string name, int index, object value);
public void set(string name, string key, object value);
}
主要是接口的定义
再来看看basicdynabean是怎么实现的,直接看public object get(string name);
/**
* return the value of a simple property with the specified name.
*
* @param name name of the property whose value is to be retrieved
* @return the property's value
*
* @exception illegalargumentexception if there is no property
* of the specified name
*/public object get(string name) { // return any non-null value for the specified property
object value = values.get(name); if (value != null) { return (value);
} // return a null value for a non-primitive property
class<?> type = getdynaproperty(name).gettype(); if (!type.isprimitive()) { return(value);
} // manufacture default values for primitive properties
if (type == boolean.type) { return (boolean.false);
} else if (type == byte.type) { return (new byte((byte) 0));
} else if (type == character.type) { return (new character((char) 0));
} else if (type == double.type) { return (new double(0.0));
} else if (type == float.type) { return (new float((float) 0.0));
} else if (type == integer.type) { return (new integer(0));
} else if (type == long.type) { return (new long(0));
} else if (type == short.type) { return (new short((short) 0));
} else { return (null);
}
}
从以上代码可以看出是在values里取值的
/**
* the set of property values for this dynabean, keyed by property name.
*/
protected hashmap<string, object> values = new hashmap<string, object>();
其实是用hashmap来实现的.
3.总结
用cglib动态删除添加属性时,虽然obj里有getusername这个方法,却不能obj.getusername()这样直接调用,想得到username的值只能通过beanmap.get("username")获取.
org.apache.commons.beanutils从源码来看是使用hashmap来实现的.
两种方式从操作角度来说和使用map的区别不大.只是它们都提供了复制属性的工具方法.
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