注解方式创建对象

创建对象的方法，比如已知对象OrderService，可以通过以下方式创建对象

1、new OrderService()

2、通过反射创建对象（本次不讲）

3、通过spring 的IOC机制

     3.1 利用无参构造函数+setter方法注入值

     3.2 利用有参构造函数直接注入

     

-----------------------------方法1 利用有参构造函数直接注入---------------------

1、创建IOrderDao

package com.longteng.lesson2.dao;

public interface IOrderDao {
    public String bookOrder(String name);
}

 2、创建IOrderDao的实体 OrderDao

package com.longteng.lesson2.dao.impl;

import com.longteng.lesson2.dao.IOrderDao;

public class OrderDao implements IOrderDao {
    @Override
    public String bookOrder(String name) {
        return name+"预订了订单";
    }
}

3、创建OrderService

package com.longteng.lesson2.service;
import com.longteng.lesson2.dao.IOrderDao;

public class OrderService {
    private String orderSkuName;
    public OrderService(String orderSkuName){
        this.orderSkuName = orderSkuName;
    }

    public void setOrderSkuName(String orderSkuName) {
        this.orderSkuName = orderSkuName;
    }

    public String getOrderSkuName() {
        return orderSkuName;
    }

    public void setiOrderDao(IOrderDao iOrderDao) {
        this.iOrderDao = iOrderDao;
    }

    IOrderDao iOrderDao;

    public String  getOrderInfo(String name){
       return iOrderDao.bookOrder(name);
    }

}

4、 创建order.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="orderDao" class="com.longteng.lesson2.dao.impl.OrderDao"></bean>
    <bean id="orderService" class="com.longteng.lesson2.service.OrderService">
        <constructor-arg name="orderSkuName" value="123456789"></constructor-arg>
        <property name="iOrderDao" ref="orderDao"></property>
    </bean>
</beans>

5、创建测试类

package com.longteng.lesson2.dao;

import com.longteng.lesson2.service.OrderService;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class OrderDaoTest {
    ApplicationContext context;
    @Before
    public void initApplication(){
        context = new ClassPathXmlApplicationContext("order.xml");
    }
    @Test
    public void test(){
        OrderService orderService = context.getBean("orderService", OrderService.class);
        System.out.println(orderService.getOrderInfo("zhou"));
        System.out.println(orderService.getOrderSkuName());
        Assert.assertEquals("成功了","zhou预订了订单",orderService.getOrderInfo("zhou"));
    }
}

6、测试结果

............
13:33:21.286 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Returning cached instance of singleton bean 'lifecycleProcessor'
13:33:21.288 [main] DEBUG org.springframework.core.env.PropertySourcesPropertyResolver - Could not find key 'spring.liveBeansView.mbeanDomain' in any property source
13:33:21.290 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Returning cached instance of singleton bean 'orderService'
zhou预订了订单
123456789

Process finished with exit code 0

----------------------------方法2 利用注解创建对象------------------------------------

1、创建IOrderDao

package com.longteng.lesson2.dao;

public interface IOrderDao {
    public String bookOrder(String name);
}

2、创建IOrderDao的实体 

package com.longteng.lesson2.dao.impl;

import com.longteng.lesson2.dao.IOrderDao;
import org.springframework.stereotype.Repository;

@Repository
public class OrderDao implements IOrderDao {
    @Override
    public String bookOrder(String name) {
        return name+"预订了订单";
    }
}

3、创建OrderService

package com.longteng.lesson2.service;
import com.longteng.lesson2.dao.IOrderDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class OrderService {
    @Autowired
    IOrderDao iOrderDao;

    public String  getOrderInfo(String name){
       return iOrderDao.bookOrder(name);
    }

}

4、 创建order.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    <context:component-scan base-package="com.longteng.lesson2.dao,com.longteng.lesson2.service"/>

</beans>

5、创建测试类

package com.longteng.lesson2.dao;

import com.longteng.lesson2.service.OrderService;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class OrderDaoTest {
    ApplicationContext context;
    @Before
    public void initApplication(){
        context = new ClassPathXmlApplicationContext("order.xml");
    }
    @Test
    public void test(){
        OrderService orderService = context.getBean("orderService", OrderService.class);
        System.out.println(orderService.getOrderInfo("zhou"));
        Assert.assertEquals("成功了","zhou预订了订单",orderService.getOrderInfo("zhou"));
    }
}

---------------------------方法3 零配置生成对象-----------------------

1、创建IOrderDao

package com.longteng.lesson2.dao;

public interface IOrderDao {
    public String bookOrder(String name);
}

2、创建IOrderDao的实体 

package com.longteng.lesson2.dao.impl;

import com.longteng.lesson2.dao.IOrderDao;
import org.springframework.stereotype.Repository;

@Repository
public class OrderDao implements IOrderDao {
    @Override
    public String bookOrder(String name) {
        return name+"预订了订单";
    }
}

3、创建OrderService

package com.longteng.lesson2.service;
import com.longteng.lesson2.dao.IOrderDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class OrderService {
    @Autowired
    IOrderDao iOrderDao;

    public String  getOrderInfo(String name){
       return iOrderDao.bookOrder(name);
    }

}

4 创建OrderService的配置类

package com.longteng.lesson2.config;

import com.longteng.lesson2.service.OrderService;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration//此处功能类似于在 order.xml编写<bean id="" class="xxxx"/>
@ComponentScan(basePackages = {"com.longteng.lesson2.dao","com.longteng.lesson2.service"})
public class OrderCfg {

    @Bean
    public OrderService getOrderService(){
        return new OrderService();
    }
}

5 创建测试类

package com.longteng.lesson2.dao;

import com.longteng.lesson2.config.OrderCfg;
import com.longteng.lesson2.service.OrderService;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class OrderDaoTest {
    ApplicationContext context;
    @Before
    public void initApplication(){
        context = new AnnotationConfigApplicationContext(OrderCfg.class);
    }
    @Test
    public void test(){
        OrderService orderService = context.getBean("orderService", OrderService.class);
        System.out.println(orderService.getOrderInfo("zhou"));
        Assert.assertEquals("成功了","zhou预订了订单",orderService.getOrderInfo("zhou"));
    }
}