Spring中的aware接口-蒲公英云

Spring中的aware接口

Spring中有很多继承于aware中的接口，这些接口到底是做什么用到的。

awre.png

aware,翻译过来是知道的，已感知的，意识到的，所以这些接口从字面意思应该是能感知到所有Aware前面的含义。

先举个BeanNameAware的例子，实现BeanNameAware接口，可以让该Bean感知到自身的BeanName（对应Spring容器的BeanId属性）属性,举个例子：

BeanNameAware接口的定义

public interface BeanNameAware extends Aware {
```
  void setBeanName(String name);
```
}
定义两个User,一个实现BeanNameAware,一个不实现。

package com.github.jettyrun.springinterface.demo.aware.beannameaware;

import org.springframework.beans.factory.BeanNameAware;

/**
- Created by jetty on 18/1/31.
  */
  public class User implements BeanNameAware{
  
  private String id;
  
  private String name;
  
  private String address;
  
  public void setBeanName(String beanName) {
```
 //ID保存BeanName的值
 id=beanName;
```
  }
  
  public String getId() {
```
 return id;
```
  }
  
  public void setId(String id) {
```
 this.id = id;
```
  }
  
  public String getName() {
```
 return name;
```
  }
  
  public void setName(String name) {
```
 this.name = name;
```
  }
  
  public String getAddress() {
```
 return address;
```
  }
  
  public void setAddress(String address) {
```
 this.address = address;
```
  }
  
  @Override
  public String toString() {
```
 return "User{" +
         "id='" + id + '\'' +
         ", name='" + name + '\'' +
         ", address='" + address + '\'' +
         '}';
```
  }
  }
package com.github.jettyrun.springinterface.demo.aware.beannameaware;

import org.springframework.beans.factory.BeanNameAware;

/**
- Created by jetty on 18/1/31.
  */
  public class User2 {
  
  private String id;
  
  private String name;
  
  private String address;
  
  public String getId() {
```
 return id;
```
  }
  
  public void setId(String id) {
```
 this.id = id;
```
  }
  
  public String getName() {
```
 return name;
```
  }
  
  public void setName(String name) {
```
 this.name = name;
```
  }
  
  public String getAddress() {
```
 return address;
```
  }
  
  public void setAddress(String address) {
```
 this.address = address;
```
  }
  
  @Override
  public String toString() {
```
 return "User{" +
         "id='" + id + '\'' +
         ", name='" + name + '\'' +
         ", address='" + address + '\'' +
         '}';
```
  }
  }

在Spring配置文件中初始化两个对象。

<bean id="lisi"  class="com.github.jettyrun.springinterface.demo.aware.beannameaware.User2">
    <property name="name" value="lisi"></property>
    <property name="address" value="火星"></property>
</bean>

main方法测试一下BeanNameAware接口所起的作用。

public static void main(String[] args) {

    ApplicationContext context = new ClassPathXmlApplicationContext("classpath:application-beanaware.xml");
    User user=context.getBean(User.class);
    System.out.println(String.format("实现了BeanNameAware接口的信息BeanId=%s,所有信息=%s",user.getId(),user.toString()));
    User2 user2=context.getBean(User2.class);
    System.out.println(String.format("未实现BeanNameAware接口的信息BeanId=%s,所有信息=%s",user2.getId(),user2.toString()));
}

运行结果

实现了BeanNameAware接口的信息BeanId=zhangsan,所有信息=User{id=’zhangsan’, name=’zhangsan’, address=’火星’}
未实现BeanNameAware接口的信息BeanId=null,所有信息=User{id=’null’, name=’lisi’, address=’火星’}