2015-05-27
周海汉 2015.5.27
Java的反射很强大，以致可以通过xml直接生成类。本文想模拟一下完全参数化的反射方式。
Car类：
package com.abloz;
public class Car {
private String name;
privateintspeed;
public Car() {
}
public Car(String name, int speed) {
this.name = name;
this.speed = speed;
}
public String getName() {
returnname;
}
public void setName(String name) {
this.name = name;
}
public int getSpeed() {
returnspeed;
}
public void setSpeed(int speed) {
this.speed = speed;
}
@Override
public String toString() {
return "Car [name=" + name + ", speed=" + speed + "]";
}
}
参数类：
package com.abloz;
public class Param {
public Param(Class<?> clazz, Object value) {
this.clazz = clazz;
this.value = value;
}
public Class<?> clazz;
public Object value;
@Override
public String toString() {
return "Param [clazz=" + clazz + ", value=" + value + "]";
}
}
参数集合容器：
package com.abloz;
import java.util.ArrayList;
import java.util.List;
public class Params {
private List<Param> params = new ArrayList<Param>();
public List<Param> getParams() {
returnparams;
}
public void add(Param param) {
params.add(param);
}
@Override
public String toString() {
return "Params [params=" + params + "]";
}
}
最关键的反射类，实现了一种简单的和一种完全参数化的反射方式
package com.abloz;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Map;
import java.util.Map.Entry;
public class ReflectCar {
public static void reflect1() {
ClassLoader loader = Thread.currentThread().getContextClassLoader();
try {
//反射法初始化类
Class clazz = loader.loadClass("com.abloz.Car");
Constructor cons = clazz.getConstructor((Class[])null);
Car car = (Car) cons.newInstance((Class[])null);
//反射法调用方法
Method method = clazz.getMethod("setName",String.class );
method.invoke(car, "my reflect car");
Method speedMethod = clazz.getMethod("setSpeed",int.class);
speedMethod.invoke(car,500);
System.out.println("reflect car1:"+car);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchMethodException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void reflect2(String className, Map<String,Params> methods) {
ClassLoader loader = Thread.currentThread().getContextClassLoader();
try {
//反射法初始化类
Class clazz = loader.loadClass(className);
Constructor cons = clazz.getConstructor((Class[])null);
Car car = (Car) cons.newInstance((Class[])null);
//反射法调用方法
for(Entry<String,Params> entry : methods.entrySet()) {
Params params = entry.getValue();
for(Param p :params.getParams()) {
Method method = clazz.getMethod(entry.getKey(), p.clazz);
method.invoke(car, p.value);
}
}
System.out.println("reflect car2:"+car);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchMethodException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
测试类：
package com.abloz;
import java.util.HashMap;
import java.util.Map;
public class TestCar {
public static void main(String[] args) {
//1. 普通的调用
Car car = new Car("mycar1",100);
System.out.println("normal car:"+car);
//2. 普通的反射, 还需要知道类的很多信息
ReflectCar.reflect1();
//3.完全盲调用，类名，方法名，参数类型和参数完全通过配置，如通过xml。 但这个还没解决多参数问题。
Map<String,Params> methods = new HashMap<String,Params>();
Params params = new Params();
params.add(new Param(String.class,"my reflect car haha"));
methods.put("setName", params);
params = new Params();
params.add(new Param(int.class,1000));
methods.put("setSpeed", params);
ReflectCar.reflect2("com.abloz.Car", methods);
}
}
执行后输出：
normal car:Car [name=mycar1, speed=100]
reflect car1:Car [name=my reflect car, speed=500]
reflect car2:Car [name=my reflect car haha, speed=1000]
参考：
http://sishuok.com/forum/blogPost/list/4229.html
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