注解注入

一、配置文件中添加 配置 <context:component-scan base-package=“com.test”/>  扫描com.test包中代码中的注解

@Component 是所有受Spring 管理组件的通用形式,不推荐使用

@Repository    对应数据层Bean

@Service        业务层Bean

@Controller    控制层Bean

 

如果不指定value，如： @Repositor 则生成的bean为类名（小写开头）

如果@Repository（“dao”） 则生成名为dao的bean

默认生成的bean为singleton类型，可用@Scope("prototype")进行声名

 

二、配置bean依赖关系

 

@Autowired 根据bean 类型从spring 上下文中进行查找,按byType自动注入

1、如果某个类的bean是唯一的，则可直接注入

@Autowired

private Student student

 

2、如果不是唯一的话，可用@Qualifier来指定注入Bean的名字

@Autowired

@Qualifier("student1")

private Student student

 

3、@Required 只能放置在setter方法上，且必须通过XML配置的setter注入

    @Required
    public void setAge(String age) {
        this.age = age;
    }

 

 

 

<?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"       
    xsi:schemaLocation="http://www.springframework.org/schema/beans        
    http://www.springframework.org/schema/beans/spring-beans-2.5.xsd        
    http://www.springframework.org/schema/context        
    http://www.springframework.org/schema/context/spring-context-2.5.xsd"> 
     
    <context:component-scan base-package="bupt.lesson3"/> 
    
</beans>

package bupt.lesson3;

import org.springframework.beans.factory.annotation.Required;
import org.springframework.stereotype.Repository;

@Repository("student")
public class Student {
    private int id;
    private String name;
    private String age;
    
    public Student(){
        
    }
    
    public Student(int id, String name, String age) {
        this.id = this.id;
        this.name = name;
        this.age = age;
    }
    
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getAge() {
        return age;
    }
    public void setAge(String age) {
        this.age = age;
    }
    
    
}

package bupt.lesson3;

import org.springframework.stereotype.Repository;

@Repository("studentDao")
public class StudentDaoImpl implements StudentDao {

    @Override
    public boolean saveStudents(Student s) {
        // TODO Auto-generated method stub
        if (s != null){
            System.out.println("学号=" + s.getId());
            System.out.println("姓名=" + s.getName());
            System.out.println("年龄=" + s.getAge());
            return true;
        }
        
        return false;
    }

}

package bupt.lesson3;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Service;

@Service("studentService")
@Scope("prototype")
public class StudentService {
    @Autowired
    @Qualifier("studentDao")
    private StudentDao sDao;
    
    @Autowired
    @Qualifier("student")
    private Student s;
    
    public Student getS() {
        return s;
    }

    public void setS(Student s) {
        this.s = s;
    }

    public StudentDao getsDao() {
        return sDao;
    }

    public void setsDao(StudentDao sDao) {
        this.sDao = sDao;
    }

    public boolean saveStudent(){
        if (sDao.saveStudents(s)){
            return true;
        }else{
            return false;
        }
    }
}

package test.bupt.lesson3;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import bupt.lesson3.StudentService;

import com.sun.org.apache.xerces.internal.util.XML11Char;

import junit.framework.Assert;
import junit.framework.TestCase;

public class testStudentService extends TestCase {

    public void testSaveStudent() {
        ApplicationContext ctx = new ClassPathXmlApplicationContext("lesson3.xml");
        StudentService stService = (StudentService) ctx.getBean("studentService");
        Assert.assertEquals(true, stService.saveStudent());
    }

}