Resource是j2ee的内容，如果要使用注解@Resource，必须引入jar文件common-annotations.jar

@Resource注解在set方法上，默认是通过ByType形式进行注入

class代码如下：

1 @Resource2     public void setBookDAO(BookDAO bookDAO) {3         System.out.println("******************setBookDAO");4         this.bookDAO = bookDAO;5         System.out.println(this.bookDAO.getClass().toString());        6     }

xml文件如下：

1 
     
      2     3   
     

@Resource注解在set方法上，也可以通过ByName指定bean

class代码如下：

1 @Resource(name="u")2     public void setBookDAO(BookDAO bookDAO) {3         System.out.println("******************setBookDAO");4         this.bookDAO = bookDAO;5         System.out.println(this.bookDAO.getClass().toString());        6     }

xml文件如下：

1 
     
         2   
     

@Component是Spring本身包含的功能，无需引入其它额外的jar文件

使用注解@Component之前，xml的头必须加上如下信息：

1 
     2        
     

@Component是标记是class类上面，class代码如下：

 

1 package com.test.service.impl; 2  3 import java.util.ArrayList; 4  5 import javax.annotation.Resource; 6  7 import org.springframework.beans.factory.annotation.Autowired; 8 import org.springframework.beans.factory.annotation.Qualifier; 9 import org.springframework.stereotype.Component;10 11 12 import com.test.dao.BookDAO;13 import com.test.domain.Book;14 import com.test.service.BookService;15 16 @Component("bookService")17 public class BookServiceImpl implements BookService{18     19     private BookDAO bookDAO;    20     public BookServiceImpl(){21         System.out.println("BookServiceImpl init!");22     }23 24     public BookDAO getBookDAO() {25         return bookDAO;26     }27     28     @Resource(name="BookDAOImpl")29     public void setBookDAO(BookDAO bookDAO) {30         System.out.println("******************setBookDAO");31         this.bookDAO = bookDAO;32         System.out.println(this.bookDAO.getClass().toString());        33     }34 35     public ArrayList
     
       getBooks() {36         // TODO Auto-generated method stub37         return null;38     }39 40     public void add(Book book) {41         System.out.println(bookDAO.getClass().toString());42         bookDAO.saveBook(book);43 44         45     }            46 47 }
     

@Component("bookService")是指定名字"bookService"，也就等同于在xml配置一个bean,如：

1 
     
         2 
     

可以通过context.getBean("bookService")获取到该实例

也可以通过@Resource(name="bookSercie")注解在set方法上，注入到变量中

下面代码是将BookDAOImpl类实例化，key变量为bookDAO

1 package com.test.dao.impl; 2  3 import java.util.List; 4 import org.springframework.stereotype.Component; 5 import com.test.dao.BookDAO; 6 import com.test.domain.Book; 7  8 @Component("bookDAO") 9 public class BookDAOImpl implements BookDAO {10     11     public void saveBook(Book book) {        12         System.out.println("save book success!");        13     }14     15     public BookDAOImpl(){16         System.out.println("BookDAOImpl inti!");17     }18     19     public List
     
       getBookList() {        20         return null;21     }22 }
     

下面的代码是通@Resource，指定name为bookDAO的实例类通过set方法注入到bookDAO变量中　　

1 package com.test.service.impl; 2  3 import java.util.ArrayList; 4 import javax.annotation.Resource; 5 import org.springframework.stereotype.Component; 6 import com.test.dao.BookDAO; 7 import com.test.domain.Book; 8 import com.test.service.BookService; 9 10 @Component("bookService")11 public class BookServiceImpl implements BookService{    12     private BookDAO bookDAO;    13     public BookServiceImpl(){14         System.out.println("BookServiceImpl init!");15     }16 17     public BookDAO getBookDAO() {18         return bookDAO;19     }20     21     @Resource(name="bookDAO")22     public void setBookDAO(BookDAO bookDAO) {23         System.out.println("******************setBookDAO");24         this.bookDAO = bookDAO;25         System.out.println(this.bookDAO.getClass().toString());        26     }27 28     public ArrayList
     
       getBooks() {29         return null;30     }31 32     public void add(Book book) {33         System.out.println(bookDAO.getClass().toString());34         bookDAO.saveBook(book);        35     }            36 }