Java---學習（7）

        spring中的類中定義的變量，方法，構造函數通過標註@Autowired註解可以從配置文件中找到相應的bean,完成自動裝配的工作。默認情況下，@Autowired是按類型來匹配相應的bean,也可以通過名稱來匹配，需要設置名稱。

       如果想使@Autowired註解生效，需要在配置文件中添加AutowiredAnnotationBeanPostProcessor，通過這個，系統將自動解析bean

<bean class=“org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor”/>

  <bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor"/>  

     1.@Autowired按類型裝配

         下面我們先建立一個UserDao類，        

package com.springfirst.Controller;

public class UserDao {

    public  String GetUserName()
    {

        return “Hello World”;
    }

}

package com.springfirst.Controller;

public class UserDao {

    public  String GetUserName()
    {

        return "Hello World";
    }

}

IUserService  接口    

package com.springfirst.Controller;

public interface IUserService {

    public  String GetUserName();
}

package com.springfirst.Controller;

public interface IUserService {

    public  String GetUserName();
}

UserService類

package com.springfirst.Controller;

import org.springframework.beans.factory.annotation.Autowired;

public class UserService implements IUserService {

    @Autowired
    private UserDao userDao;

    public String GetUserName() {
        // TODO Auto-generated method stub
        return userDao.GetUserName();
    }

}

package com.springfirst.Controller;

import org.springframework.beans.factory.annotation.Autowired;

public class UserService implements IUserService {

    @Autowired
    private UserDao userDao; 

    public String GetUserName() {
        // TODO Auto-generated method stub
        return userDao.GetUserName();
    }

}

 在controller中我們定義userService,系統會進行自動匹配裝載，找到userService的具體實現

@Autowired
private IUserService userService;


@RequestMapping(value=“userdetail”)
public String userdetail(ModelMap model)
{
    String name=userService.GetUserName();
    System.out.print(name);
    model.addAttribute(”username”,name);
    return “userdetail”;
}

   @Autowired
    private IUserService userService;


    @RequestMapping(value="userdetail")
    public String userdetail(ModelMap model)
    {
        String name=userService.GetUserName();
        System.out.print(name);
        model.addAttribute("username",name);
        return "userdetail";
    }

  配置文件      

<?xml version=“1.0” encoding=“UTF-8”?>
<beans xmlns=”http://www.springframework.org/schema/beans”
    xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance” xmlns:context=“http://www.springframework.org/schema/context”
    xmlns:aop=”http://www.springframework.org/schema/aop” xmlns:p=“http://www.springframework.org/schema/p”
    xmlns:cache=”http://www.springframework.org/schema/cache” xmlns:repo=“http://www.springframework.org/schema/data/repository”
    xmlns:tx=”http://www.springframework.org/schema/tx” xmlns:jpa=“http://www.springframework.org/schema/data/jpa”
    xsi:schemaLocation=”http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
        http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
        http://www.springframework.org/schema/data/repository http://www.springframework.org/schema/data/repository/spring-repository-1.7.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
            http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd ”
    default-lazy-init=“true”>

    <description>Spring配置</description>
 <!– 該 BeanPostProcessor 將自動起作用，對標註 @Autowired 的 Bean 進行自動注入 –>
    <bean class=“org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor”/>

 <bean id=”userService” class=“com.springfirst.Controller.UserService”/>
  <bean id=”userDao” class=“com.springfirst.Controller.UserDao”/>

</beans>

<?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"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:cache="http://www.springframework.org/schema/cache" xmlns:repo="http://www.springframework.org/schema/data/repository"
    xmlns:tx="http://www.springframework.org/schema/tx" xmlns:jpa="http://www.springframework.org/schema/data/jpa"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
        http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
        http://www.springframework.org/schema/data/repository http://www.springframework.org/schema/data/repository/spring-repository-1.7.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
            http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd "
    default-lazy-init="true">

    <description>Spring配置</description>
 <!-- 該 BeanPostProcessor 將自動起作用，對標註 @Autowired 的 Bean 進行自動注入 -->  
    <bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor"/>  

 <bean id="userService" class="com.springfirst.Controller.UserService"/>
  <bean id="userDao" class="com.springfirst.Controller.UserDao"/>

</beans>

上面的自動裝配是按類型進行匹配的，Spring會自動從配置文件中找到相應的類型，進行裝載

         使用方法進行註解  

private IUserService userService;

@Autowired()
public void setUserService(IUserService userService) {
    this.userService = userService;
}

  private IUserService userService;

    @Autowired()
    public void setUserService(IUserService userService) {
        this.userService = userService;
    }

           使用構造函數進行註解     

private IUserService userService;

    @Autowired
    public  UserController(IUserService userService)
    {
        this.userService=userService;

    }

private IUserService userService;

    @Autowired
    public  UserController(IUserService userService)
    {
        this.userService=userService;

    }

          2.@Autowired按名稱裝配

               按名稱裝載的時候,@Autowired需要配合@Qualifier一起使用，通過@Qualifier可以指定名稱。
               如果兩個類同時繼承一個接口，這個時候我們要通過@Qualifier來指定名稱進行匹配，所謂名稱就是XML文件中的bean的id, 這裏我們定義了Employee類和UserService類都繼承IUserService接口

               如果有兩個類同時繼承一個接口，使用的時候如果不通過名稱指定，會報異常。

package com.springfirst.Controller;

import org.springframework.beans.factory.annotation.Autowired;

public class Employee implements IUserService {



    public String GetUserName() {
        // TODO Auto-generated method stub
        return  “Employee”;
    }

}

package com.springfirst.Controller;

import org.springframework.beans.factory.annotation.Autowired;

public class Employee implements IUserService {



    public String GetUserName() {
        // TODO Auto-generated method stub
        return  "Employee";
    }

}

          

       

package com.springfirst.Controller;

import org.springframework.beans.factory.annotation.Autowired;

public class UserService implements IUserService {

    @Autowired
    private UserDao userDao;

    public String GetUserName() {
        // TODO Auto-generated method stub
        return userDao.GetUserName();
    }

}

package com.springfirst.Controller;

import org.springframework.beans.factory.annotation.Autowired;

public class UserService implements IUserService {

    @Autowired
    private UserDao userDao; 

    public String GetUserName() {
        // TODO Auto-generated method stub
        return userDao.GetUserName();
    }

}

            在xml中定義了bean

         

<?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”
    xmlns:aop=“http://www.springframework.org/schema/aop” xmlns:p=“http://www.springframework.org/schema/p”
    xmlns:cache=“http://www.springframework.org/schema/cache” xmlns:repo=“http://www.springframework.org/schema/data/repository”
    xmlns:tx=“http://www.springframework.org/schema/tx” xmlns:jpa=“http://www.springframework.org/schema/data/jpa”
    xsi:schemaLocation=”http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
        http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
        http://www.springframework.org/schema/data/repository http://www.springframework.org/schema/data/repository/spring-repository-1.7.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
            http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd ”
    default-lazy-init=“true”>

    <description>Spring配置</description>
 <!– 該 BeanPostProcessor 將自動起作用，對標註 @Autowired 的 Bean 進行自動注入 –>
    <bean class=“org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor”/>

 <bean id=“userService” class=“com.springfirst.Controller.UserService”/>
  <bean id=“employee” class=“com.springfirst.Controller.Employee”/>
  <bean id=“userDao” class=“com.springfirst.Controller.UserDao”/>

</beans>

<?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"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:cache="http://www.springframework.org/schema/cache" xmlns:repo="http://www.springframework.org/schema/data/repository"
    xmlns:tx="http://www.springframework.org/schema/tx" xmlns:jpa="http://www.springframework.org/schema/data/jpa"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
        http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd
        http://www.springframework.org/schema/data/repository http://www.springframework.org/schema/data/repository/spring-repository-1.7.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
            http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd "
    default-lazy-init="true">

    <description>Spring配置</description>
 <!-- 該 BeanPostProcessor 將自動起作用，對標註 @Autowired 的 Bean 進行自動注入 -->  
    <bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor"/>  

 <bean id="userService" class="com.springfirst.Controller.UserService"/>
  <bean id="employee" class="com.springfirst.Controller.Employee"/>
  <bean id="userDao" class="com.springfirst.Controller.UserDao"/>

</beans>

            在Controller中我們指定使用名稱爲 userService的bean，通過@Qualifier 指定，代碼如下

          

private IUserService userService;

 //這裏我們使用id爲userService的bean
@Autowired
public  UserController(@Qualifier(“userService”)IUserService userService)
{
    this.userService=userService;

}

  private IUserService userService;

     //這裏我們使用id爲userService的bean
    @Autowired
    public  UserController(@Qualifier("userService")IUserService userService)
    {
        this.userService=userService;

    }