Spring5框架学习1(ioc容器)

小编主要介绍的是ioc中的两大重要作用：创建对象和DI(属性注入)
Spring框架的底层原理  :xml解析技术，工厂模式，反射 

(小编就直接使用现成的图做一下描述)

对象的创建（基于xml文件)

 class类

package com.java.sping5;
//尝试用sping来创建对象并调用方法
public class User {
    public void  add(){
        System.out.println("add a user");
    }
}

package com.java.sping5;

public class Oder {
    private String oname;
    private String oadress;

    public Oder(String oname, String oadress) {
        this.oname = oname;
        this.oadress = oadress;
    }

    @Override
    public String toString() {
        return "Oder{" +
                "oname='" + oname + ''' +
                ", oadress='" + oadress + ''' +
                '}';
    }
    public    void output (){
        System.out.println(oname);
        System.out.println(oadress);
    }
}

package com.java.sping5;

public class Book {
    private  String bname;
    private  String banthor;
    public void setBname(String bname) {
        this.bname = bname;
    }
    public void setBanthor(String banthor) {
        this.banthor = banthor;
    }

    @Override
    public String toString() {
        return "Book{" +
                "bname='" + bname + ''' +
                ", banthor='" + banthor + ''' +
                '}';
    }
}

属性注入

    
 
    
     
         
             张三
             李四
             王伟
         
     
     
     
         
             张三
             李四
             王伟
         
     
     
     
         
     
     
     
         
             Mysql
             Rides
         
     
     
       
         
             
             
         
     
 
    
        
    
    
        
    

对象创建基于(注解)

首先是在xml文件中开启文件扫描

接口和实现类

package com.java.spring.Dao;
public interface UserDao {
    public void add();
}

//实现类
package com.java.spring.Dao;

import org.springframework.stereotype.Repository;

@Repository(value = "userdaoimpl")
public class UserDaoimpl implements UserDao{
    @Override
    public void add() {
        System.out.println("userdao add");
    }
}

注解实现对象创建和测试

package com.java.spring;
import com.java.spring.Dao.UserDao;
import com.java.spring.Dao.UserDaoimpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.expression.evaluationException;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Controller;
import org.springframework.stereotype.Service;
//注解来创建对象 如果不添加(value="xxx") 默认是类的首字符小写名称
//@Component(value ="user") @Service
@Controller
public class User {
    @Autowired  // 根据类型进行注入  注解后不需set方法
    @Qualifier(value = "userdaoimpl") //当一个接口的实现类较多的时候，就可以根据名称找的需要的类
    private UserDao userDao;
    @Value("张三")
    private  String uname;
    public void add(){
        System.out.println(uname);
        userDao.add();
    }
}

package com.java.spring;

import com.java.comfriger.Springcomfeiger;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Springtest {

    @Test
    public void test1(){
        ApplicationContext context=
                new ClassPathXmlApplicationContext("Bean4.xml");
        User user = context.getBean("user", User.class);
        System.out.println(user);
        user.add();
    }
    @Test
    public void test2(){
        ApplicationContext context=
                new AnnotationConfigApplicationContext(Springcomfeiger.class);
        User user = context.getBean("user", User.class);
        System.out.println(user);
        user.add();
    }
}