spring框架：对象类型属性及复杂类型属性的注入

一、对象属性类型的注入：

以MVC三层架构为例（Service、Controller、Dao）,通常service和controller层需要对dao层的数据进行访问操作，这里以将dao层数据注入到Service层作为例子来说明

1、创建一个dao层的接口类

package com.xawl.spring.dao;

public interface UserDao {
    void method1();
}

2、实现该接口的方法

package com.xawl.spring.dao;

public class UserDaoImp implements UserDao {
    @Override
    public void method1() {
        System.out.println("this is UserDao");
    }
}

3、创建Service层下的调用类

package com.xawl.spring.service;

import com.xawl.spring.dao.UserDao;

public class UserService {
    private UserDao userDao;

    public UserDao getUserDao() {
        return userDao;
    }

    public void setUserDao(UserDao userDao) {
        this.userDao = userDao;
    }

    public void userservice() {
        System.out.println("this is userservice");
        this.userDao.method1();
    }

    @Override
    public String toString() {
        return "UserService{" +
                "userDao=" + userDao +
                '}';
    }
}

4、配置spring.xml（ref表示到跳转id）

5、创建测试类

package springdi;

import com.xawl.spring.service.UserService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestService {
    public static void main(String[] args) {
        //获取资源文件
        String resources = "spring.xml";
        //根据资源文件创建对象
        ApplicationContext context = new ClassPathXmlApplicationContext(resources);
        UserService userService = (UserService)context.getBean("userService");
        System.out.println(userService);
        userService.getUserDao();
        userService.userservice();
    }
}

6、输出结果

UserService{userDao=com.xawl.spring.dao.UserDaoImp@2f686d1f}
this is userservice
this is UserDao

二、复杂类型属性注入

数组、set、map、list四种类型的属性注入

1、创建bean实类

package com.xawl.spring.di;

import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class Demo3 {
    private String[] arrs;
    private List list;
    private Map map;
    private Set set;

    public String[] getArrs() {
        return arrs;
    }

    public void setArrs(String[] arrs) {
        this.arrs = arrs;
    }

    public List getList() {
        return list;
    }

    public void setList(List list) {
        this.list = list;
    }

    public Map getMap() {
        return map;
    }

    public void setMap(Map map) {
        this.map = map;
    }

    public Set getSet() {
        return set;
    }

    public void setSet(Set set) {
        this.set = set;
    }

    @Override
    public String toString() {
        return "Demo3{" +
                "arrs=" + Arrays.toString(arrs) +
                ", list=" + list +
                ", map=" + map +
                ", set=" + set +
                '}';
    }
}

2、配置spring.xml

    
    
    
    
        
    
    
    
        
    
    
    
    
        
    
    
    
        
        
            
                1
                2
                3
            
        
        
        
            
                11
                22
                33
            
        
        
        
            
                111
                222
                333
            
        
        
        
            
        
    

3、创建测试类

package springdi;

import com.xawl.spring.di.Demo3;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TestDemo3 {
    public static void main(String[] args) {
        //获取数据源
        String resources = "spring.xml";
        //创建对象
      ApplicationContext context = new ClassPathXmlApplicationContext(resources);
        Demo3 demo3 = (Demo3) context.getBean("demo3");
        System.out.println(demo3);
    }
}

4、输出结果

Demo3{arrs=[1, 2, 3], list=[11, 22, 33], map={1=01, 2=02, 3=03}, set=[111, 222, 333]}

三、IOC和DI的关系和区别

IOC是容器，把对象交给spring处理

DI依赖注入，通过spring向类的属性设置值

依赖注入（DI）不能单独存在，需要在控制反转(IOC)的基础之上完成操作