第一种  setXXX形式的注入

package com.yangwei.shop.util;import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Properties;import com.yangwei.shop.dao.IDaoFactory;/**dao工具类，主要使用反射机制*/
public class DaoUtil {/*** 思路：获取自己的所有方法，在判断是否有setXXX方法，如果有就对这个方法进行对象注入*/public static void injectDao(Object obj){try {//1,获取自己定义的所有方法Method[] methods=obj.getClass().getDeclaredMethods();for(Method method:methods){//获取方法名String mn=method.getName();//2,查找set方法  if(mn.startsWith("set")){//比如 setUserDaomn=mn.substring(3);mn=mn.substring(0, 1).toLowerCase()+mn.substring(1);//3,从我们定义的工厂中获取dao对象Object o=DaoUtil.createDaoFactory().getDao(mn);//4，利用反射调用方法注入//method是setXXX方法，调用者是this，参数是工厂取的具体dao对象
                    method.invoke(obj, o);}}} catch (SecurityException e) {e.printStackTrace();} catch (IllegalArgumentException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();}}public static IDaoFactory createDaoFactory(){Properties prop = PropertiesUtil.getDaoProp();try {Class clz=Class.forName((String)prop.get("factory"));String mm="getInstance";Method method=clz.getMethod(mm);//调用静态方法   使用类来调用return (IDaoFactory)method.invoke(clz);    } catch (ClassNotFoundException e) {// TODO Auto-generated catch block
            e.printStackTrace();}catch (SecurityException e) {// TODO Auto-generated catch block
            e.printStackTrace();} catch (NoSuchMethodException e) {// TODO Auto-generated catch block
            e.printStackTrace();} catch (IllegalArgumentException e) {// TODO Auto-generated catch block
            e.printStackTrace();} catch (IllegalAccessException e) {// TODO Auto-generated catch block
            e.printStackTrace();} catch (InvocationTargetException e) {// TODO Auto-generated catch block
            e.printStackTrace();}return null;}}

    public BaseDao(){DaoUtil.injectDao(this);}

package com.yangwei.shop.test;import com.yangwei.shop.util.DaoUtil;public class BaseTest {public BaseTest(){DaoUtil.injectDao(this);}
}

package com.yangwei.shop.test;import org.junit.Test;import com.yangwei.shop.dao.UserDao;public class TestInject extends BaseTest{/*** 测试set形式的依赖注入*/private UserDao userDao=null;@Testpublic void testSetDao(){System.out.println(userDao);}public UserDao getUserDao() {return userDao;}public void setUserDao(UserDao userDao) {this.userDao = userDao;}}

第二种  annotation形式的注入

package com.yangwei.shop.entity;import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;/*** 用这个annotation标注需要进行依赖注入的方法* @ShopDi("userDao"),说明需要注入userDao对象* 如果是@ShopDi就规定使用setXXX注入**/
//必须让它在运行时能够执行
@Retention(RetentionPolicy.RUNTIME)
public @interface ShopDi {/*** value是Annotation的默认属性，在定义的时候可以不用vaule=""定义，而是直接通过* @ShopDi("XXX")* 特别注意，当需要定义两个以上的属性时，默认属性就不起作用了，此时需要如下形式定义* @ShopDi(value="XXX",abc="YYY")*/String value() default "";
}

/*** 使用注解的形式，完成对Dao对象的注入* @param obj*/public static void injectDao1(Object obj){try {//针对属性的注解Field[] fields=obj.getClass().getDeclaredFields();for(Field field:fields){//有ShopDi的注解的属性if(field.isAnnotationPresent(ShopDi.class)){ShopDi shopDi=field.getAnnotation(ShopDi.class);String value=shopDi.value();if(value==null || "".equals(value.trim())){//为空时，使用属性名称value=field.getName();}Object o=DaoUtil.createDaoFactory().getDao(value);//当属性被private修饰时，一定要设置可访问为truefield.setAccessible(true);field.set(obj, o);}}} catch (SecurityException e) {e.printStackTrace();} catch (IllegalArgumentException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}}

package com.yangwei.shop.test;import com.yangwei.shop.util.DaoUtil;public class BaseTest {public BaseTest(){DaoUtil.injectDao(this);}
}

package com.yangwei.shop.test;
import org.junit.Test;import com.yangwei.shop.dao.UserDao;
import com.yangwei.shop.entity.ShopDi;public class TestAnnotation extends BaseTest{@ShopDi("userDao")private UserDao userDao;@Testpublic void abc(){System.out.println(userDao);}  }