Spring的DI初步

DI：依赖注入

第一个DEMO：域属性注入

　　java类：（Car类和Stu类，学生有一辆小汽车）

 1 package cn.dawn.day02di;
 2 /**
 3  * Created by Dawn on 2018/3/3.
 4  *///小汽车类public class Car {
 5     private String type;
 6     private String color;
 7
 8     public String getType() {
 9         return type;
10     }
11
12     public void setType(String type) {
13         this.type = type;
14     }
15
16     public String getColor() {
17         return color;
18     }
19
20     public void setColor(String color) {
21         this.color = color;
22     }
23 }

package cn.dawn.day02di;
/**
 * Created by Dawn on 2018/3/3.
 *///学生类public class Stu {
    private String name;
    private Integer age;
    private Car car;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Car getCar() {
        return car;
    }

    public void setCar(Car car) {
        this.car = car;
    }
}

配置xml中

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <!--汽车-->
    <bean id="car" class="cn.dawn.day02di.Car">
        <property name="type" value="奔驰"></property>
        <property name="color" value="红色"></property>
    </bean>
    <!--学生-->
    <!--这儿的小汽车不能用value，用ref引用上面的那个汽车car-->
    <bean id="stu" class="cn.dawn.day02di.Stu">
        <property name="name" value="孟六"></property>
        <property name="age" value="20"></property>
        <property name="car" ref="car"></property>
    </bean>

</beans>

　测试类

package cn.dawn.day02;

import cn.dawn.day02di.Stu;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
 * Created by Dawn on 2018/3/3.
 */public class test20180303 {
    @Test
    /*域属性*/
    public void t01(){
        ApplicationContext context=new ClassPathXmlApplicationContext("ApplicationContext-day02.xml");
        Stu stu = (Stu) context.getBean("stu");
        System.out.println(stu.getName()+"开"+stu.getCar().getType());
    }
}

第二个Demo：打印机案例

  项目架构

 1 package cn.dawn.day03printer.ink;
 2 /**
 3  * Created by Dawn on 2018/3/3.
 4  *//*墨盒*/public interface Ink {
 5     public String getInkColor();
 6 }
 7
 8
 9 package cn.dawn.day03printer.ink;
10 /**
11  * Created by Dawn on 2018/3/3.
12  *//*彩色墨盒*/public class ColorInk implements Ink {
13     public String getInkColor() {
14         return "彩色墨盒";
15     }
16 }
17
18
19
20 package cn.dawn.day03printer.ink;
21 /**
22  * Created by Dawn on 2018/3/3.
23  *//*黑白墨盒*/public class BlackInk implements Ink {
24     public String getInkColor() {
25         return "黑白墨盒";
26     }
27 }
28
29
30
31 package cn.dawn.day03printer.paper;
32 /**
33  * Created by Dawn on 2018/3/3.
34  *//*纸张*/public interface Paper {
35     public String getPagerSize();
36 }
37
38
39
40 package cn.dawn.day03printer.paper;
41 /**
42  * Created by Dawn on 2018/3/3.
43  *//*B5纸张*/public class B5Paper implements Paper{
44
45     public String getPagerSize() {
46         return "B5纸";
47     }
48 }
49
50
51
52 package cn.dawn.day03printer.paper;
53 /**
54  * Created by Dawn on 2018/3/3.
55  *//*A4纸张*/public class A4Paper implements Paper {
56     public String getPagerSize() {
57         return "A4纸";
58     }
59 }
60
61
62
63 package cn.dawn.day03printer.printer;
64
65 import cn.dawn.day03printer.ink.Ink;
66 import cn.dawn.day03printer.paper.Paper;
67 /**
68  * Created by Dawn on 2018/3/3.
69  *//*打印机*/public class Printer {
70     /*墨盒*/
71     private Ink ink;
72     /*纸张*/
73     private Paper paper;
74     /*打印方法*/
75     public void print(){
76         System.out.println("我们的喷墨打印机，用"+ink.getInkColor()+"和"+paper.getPagerSize()+"打印出了------》我爱Spring");
77     }
78
79
80     public Ink getInk() {
81         return ink;
82     }
83
84     public void setInk(Ink ink) {
85         this.ink = ink;
86     }
87
88     public Paper getPaper() {
89         return paper;
90     }
91
92     public void setPaper(Paper paper) {
93         this.paper = paper;
94     }
95 }

　　配置文件中：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <!--墨盒-->
    <bean id="ink" class="cn.dawn.day03printer.ink.ColorInk"></bean>
    <!--纸张-->
    <bean id="paper" class="cn.dawn.day03printer.paper.A4Paper"></bean>
    <!--打印机-->
    <bean id="printer" class="cn.dawn.day03printer.printer.Printer">
        <property name="ink" ref="ink"></property>
        <property name="paper" ref="paper"></property>
     </bean>
</beans>

　　单测方法

package cn.dawn.day03;

import cn.dawn.day02di.Stu;
import cn.dawn.day03printer.printer.Printer;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
 * Created by Dawn on 2018/3/3.
 */public class test20180303 {
    @Test
    /*打印机案例*/
    public void t01(){
        ApplicationContext context=new ClassPathXmlApplicationContext("ApplicationContext-day03.xml");
        Printer printer = (Printer) context.getBean("printer");
        printer.print();
    }
}

原文地址：https://www.cnblogs.com/wh1520577322/p/9379779.html