spring高级功能

自动装配

Spring能自动装配Bean与Bean之间的依赖关系，无需使用ref显示指定依赖Bean。

通过<beans.../>元素的default-autowire属性指定，也可以通过autowire属性指定。

no:不使用自动装配，必须通过ref定义。

byName:根据属性名自动装配

byType:根据属性类型自动装配

constructor:根据属性名自动装配,用构造函数

autodetect:由beanFactory决定用byType或constructor，有默认构造函数，用byType；

Spring启动时将自动搜索，自动装配。若不想自动装配，可使用

autowire-candidate="false"

<beans default-autowire-candidates="*user"（4.0不起作用*）

例1：

Reply.java

package auto;

public class Reply {
private String id;
private String title;
private String content;
private Topic topic;

// 实现构造函数

public Reply() {
System.out.println("reply被创建");
}

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public String getTitle() {
return title;
}

public void setTitle(String title) {
this.title = title;
}

public String getContent() {
return content;
}

public void setContent(String content) {
this.content = content;
}

public Topic getTopic() {
return topic;
}

public void setTopic(Topic topic) {
this.topic = topic;
}

}

Topic.java

package auto;

import java.util.List;

public class Topic {
private String id;
private String title;
private String Content;

// 集合继承
private List<String> names;

public List<String> getNames() {
return names;
}

public void setNames(List<String> names) {
this.names = names;
}

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public String getContent() {
return Content;
}

public void setContent(String content) {
Content = content;
}

public String getTitle() {
return title;
}

public void setTitle(String title) {
this.title = title;
}

}

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans default-autowire-candidates="*pic"
xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd"> 
<bean name="topic" class="auto.Topic">
<property name="id">
<value>1</value>
</property>
<property name="title">
<value>xxxx</value>
</property>
<property name="content">
<value>yy</value>
</property>
</bean>
<!-- autowire注入，通过byName找name注入,当spring初始化，id跟name一样效果(name可以放多个，id只能放一个 )，不能有同名。autowire-candidate="false"不让它自动装配（4.0版本byName不能出现结果） -->
<bean name="reply" class="auto.Reply"   autowire="byName">
<!-- <bean id="reply" class="auto.Reply" autowire="byName">-->
<!-- 根据类型注入,如果有多个对象是抛出异常 ，两个bean会出错 ,根据byType查询时 autowire-candidate="false"起作用
<bean id="reply" class="auto.Reply" autowire="byType" > -->
<property name="id">
<value>1</value>
</property>
<property name="title">
<value>zhenhao</value>
</property>
<property name="content">
<value>xuexi</value>
</property>
<!-- 同时注入和ref同时使用，以ref为主 -->
</bean>
</beans>

测试代码

/*
* 根据XML文件查询
*/
ApplicationContext context=new  ClassPathXmlApplicationContext("applicationContext.xml");
Reply  reply=context.getBean("reply",Reply.class);
System.out.println(reply.getTopic().getTitle());

运行结果：

reply被创建

xxxx

通过配置类查询，构造一个注释配置类

Config.java

package cofig;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import auto.Topic;

//注解注入,将config变为配置类
@Configuration
public class Config {
//给属性赋值
@Value(value="csdn")
public String name;

//得到对象，生成对象名为topic3
@Bean(name="topic3")
public Topic getTopic(){
Topic topic =new Topic();
topic.setTitle("java");
topic.setContent("ccxcc");
return topic;
}

}

测试代码

/*
* 通过配置类查询，构造一个注释配置类，可以进行人工干预
*/

ApplicationContext context=new
AnnotationConfigApplicationContext(Config.class); Topic
topic=context.getBean("topic3",Topic.class);

System.out.println(topic.getTitle()+"--"+topic.getContent());

运行结果：

java--ccxcc

继承父类标签

在XML文件中配置

<!--  默认找topic的类，继承父标签的值 -->
<bean  name="topic1"  parent="topic">
<property name="names">
<!--    merge="true"回合上面的，合并一起，合并集合的值 -->
<list  merge="true">
<value>789</value>
</list></property>
</bean>

测试代码

/**
* 继承集合类，输出集合中的所有属性
*/

ApplicationContext context=new
ClassPathXmlApplicationContext("applicationContext.xml"); Topic
topic=context.getBean("topic1",Topic.class);

System.out.println(topic.getNames());

运行结果：

reply被创建

[123, 245, 789]

不同类型的继承

Talk.java

package auto;

import java.util.List;

public class Talk {
private String id;
private String title;
private String Content;
private List<String> names;

public String getId() {
return id;
}

// 实现构造函数

public Talk() {

System.out.println("talk被创建");
}

public void setId(String id) {
this.id = id;
}

public String getTitle() {
return title;
}

public void setTitle(String title) {
this.title = title;
}

public String getContent() {
return Content;
}

public void setContent(String content) {
Content = content;
}

public List<String> getNames() {
return names;
}

public void setNames(List<String> names) {
this.names = names;
}

}

在XML文件中配置

<!-- 不同类型的继承 -->
<bean  name="talk"  class="auto.Talk"  parent="topic">

</bean>

测试代码

/**
* 不同类型的继承
*/
ApplicationContext context=new
ClassPathXmlApplicationContext("applicationContext.xml"); Talk
topic=context.getBean("talk",Talk.class);

System.out.println(topic.getNames());
System.out.println(topic.getTitle());

运行结果：

talk被创建

reply被创建

[123, 245]

xxxx

工厂TopicFactory.java

package factory;

import org.springframework.beans.factory.FactoryBean;

import auto.Topic;

public class TopicFactory  implements  FactoryBean<Topic>{

private Topic topic;
//返回对象
@Override
public Topic getObject() throws Exception {
//单例模式
if(topic==null){
topic=new Topic();
}
return topic;

}
//返回对象类型
@Override
public Class<?> getObjectType() {

return Topic.class;
}

//判断对象是否是单例
@Override
public boolean isSingleton() {

return true;
}

}

bean.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans default-autowire-candidates="*pic"
xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd"> 
<!-- 测试depend-on
不加depends-on="reply"
根据顺序有关。如果加就跟顺序无关;lazy-init="true"懒加载等待完成后在运行<bean  name="        reply" class="auto.Reply"  lazy-init="true"></bean>
<bean  name="talk" class="auto.Talk"  depends-on="reply"></bean>

-->

<!-- 证明工厂是否是单例 ，配置单例工厂--> <bean name="topic" class="factory.TopicFactory"> </bean> </beans>

测试代码：

// 工厂
ApplicationContext context = new ClassPathXmlApplicationContext(
"bean.xml"); Topic topic = context.getBean("topic", Topic.class);
topic.setId("110"); System.out.println(topic.getId()); Topic topic1 =
context.getBean("topic", Topic.class);
System.out.println(topic1.getId());

运行结果：

110

110