Spring架构学习（1）编码实现依赖注入

本示例通过生产者和消费者的例子演示如何通过普通编码实现spring的依赖注入

首先编写商品类、生产者、消费者代码如下

package my.spring.pojo;public class Product {public int serialno;public String name;public Product(int id){setSerialno(id);setName("product"+id);}public int getSerialno() {return serialno;}public void setSerialno(int serialno) {this.serialno = serialno;}public String getName() {return name;}public void setName(String name) {this.name = name;}}

 

package my.spring.pojo;import java.util.List;public class Producer {private static int counter=0;private int id;public Producer(int id){this.id=id;}public int getId() {return id;}public void setId(int id) {this.id = id;}public void produce(List<Product> products){this.counter++;Product product=new Product(counter);products.add(products.size(),product);System.out.println("producer:product"+counter+" current size:"+products.size());}}

 

package my.spring.pojo;import java.util.List;public class Consumer {private int id;public Consumer(int id){this.id=id;}public int getId() {return id;}public void setId(int id) {this.id = id;}public void consume(List<Product> products){if(products!=null && products.size()>0){Product product=products.get(0);System.out.println("consumer:product"+product.getSerialno()+" current size:"+products.size());products.remove(0);}}}

然后需要一个调度者统一管理生产者、消费者以及产品队列，因此需要将生产者、消费者注入调度者中

package my.spring.pojo;import java.util.ArrayList;import java.util.List;public class Dispatcher {private Producer producer;private Consumer consumer;private static List<Product> products;public Dispatcher(){this.products=new ArrayList<Product>();}public Dispatcher(Producer producer,Consumer consumer){this.producer=producer;this.consumer=consumer;this.products=new ArrayList<Product>();}public void setProducer(Producer producer) {this.producer = producer;}public void setConsumer(Consumer consumer) {this.consumer = consumer;}public void dispatch(){Thread thread1=new Thread(){public void run(){while(true){producer.produce(products);try {int ms=(int) (Math.random()*1000);sleep(ms);} catch (InterruptedException e) {e.printStackTrace();}}};};Thread thread2=new Thread(){public void run(){while(true){consumer.consume(products);try {int ms=(int) (Math.random()*500);sleep(ms);} catch (InterruptedException e) {e.printStackTrace();}}}};thread1.start();thread2.start();thread1.run();thread2.run();}}

 

然后就要写实现类了

package my.spring.demo;import org.springframework.beans.factory.BeanFactory;import org.springframework.beans.factory.config.ConstructorArgumentValues;import org.springframework.beans.factory.support.AbstractBeanDefinition;import org.springframework.beans.factory.support.BeanDefinitionRegistry;import org.springframework.beans.factory.support.DefaultListableBeanFactory;import org.springframework.beans.factory.support.RootBeanDefinition;import my.spring.pojo.Consumer;import my.spring.pojo.Dispatcher;import my.spring.pojo.Producer;public class CodeImpl {public void run(){//Producer producer=new Producer(101);//Consumer consumer=new Consumer(24);////Dispatcher dispatcher=new Dispatcher(producer, consumer);//dispatcher.dispatch();DefaultListableBeanFactory beanRegistry=new DefaultListableBeanFactory();BeanFactory container=bindViaCode(beanRegistry);Dispatcher dispatcher=(Dispatcher)container.getBean("dispatcherA");dispatcher.dispatch();}public static BeanFactory bindViaCode(BeanDefinitionRegistry registry){//设置生产者和消费者的构造器参数ConstructorArgumentValues productArgumentValues=new ConstructorArgumentValues();productArgumentValues.addIndexedArgumentValue(0,101);ConstructorArgumentValues consumerArgumentValues=new ConstructorArgumentValues();consumerArgumentValues.addIndexedArgumentValue(0,28);AbstractBeanDefinition producer=new RootBeanDefinition(Producer.class,productArgumentValues,null);AbstractBeanDefinition consumer=new RootBeanDefinition(Consumer.class,consumerArgumentValues,null);AbstractBeanDefinition dispatcher=new RootBeanDefinition(Dispatcher.class);registry.registerBeanDefinition("producerA", producer);registry.registerBeanDefinition("consumerA", consumer);registry.registerBeanDefinition("dispatcherA", dispatcher);//通过构造器注入参数ConstructorArgumentValues argumentValues=new ConstructorArgumentValues();argumentValues.addIndexedArgumentValue(0, producer);argumentValues.addIndexedArgumentValue(1, consumer);dispatcher.setConstructorArgumentValues(argumentValues);//通过setter方法注入//MutablePropertyValues propertyValues=new MutablePropertyValues();//propertyValues.addPropertyValue("producer", producer);//propertyValues.addPropertyValue("consumer", consumer);return (BeanFactory) registry;}}

通过单元测试运行可得

 

现对几个主要的类作简要说明：

例子中BeanFactory、BeanDefinationRegistry、DefaultListableBeanFactory的关系为

1、BeanDefination：定义的一个类实例（顶层接口），其中包含了属性（property）、构造器（constructor）等具体实现，为实现属性等元数据修改提供统一接口；

从包含的方法可知其定义了各种set和get类基本属性（类名、父类名、抽象、单例、延迟加载、描述、依赖、源定义类等等），功能十分强大。其直接继承的抽象类AbstrcatBeanFactory，再往下就是ChildBeanDefinition, GenericBeanDefinition, RootBeanDefinition，其中GenericBeanDefination比较常用。

2、BeanDefinationRegistry：BeanDefination的注册接口，说俗了也就是BeanDefination的一个容器，本身继承了AliasRegistry，即定义了对类别名操作函数；其子类DefaultListableBeanRegistry为最经典的类注册器，其中最为重要属性如下：

/** Map of bean definition objects, keyed by bean name */private final Map<String, BeanDefinition> beanDefinitionMap = new ConcurrentHashMap<String, BeanDefinition>(64);

 

3、ConstructorArgumentValues：构造器的参数容器

private final Map<Integer, ValueHolder> indexedArgumentValues = new LinkedHashMap<Integer, ValueHolder>(0);private final List<ValueHolder> genericArgumentValues = new LinkedList<ValueHolder>();

4、MutablePropertyValues：可变参数容器

private final List<PropertyValue> propertyValueList;private Set<String> processedProperties;private volatile boolean converted = false;