• Spring DI


     

    DI(Dependency Injection),依赖注入是一种技术,即一个对象提供另一个对象的依赖关系。

    构造注入

    前提:类型必须有构造,index与参数类型保持一致

    1.创建Student类

    package cn.happy.day03aop.aop;
    
    /**
     * Created by Administrator on 2018/3/5.
     */
    //构造注入
    public class Student {
        private String name;
        private Integer age;
    
        public Student() {
        }
    
        public Student(String name, Integer age) {
            this.name = name;
            this.age = age;
        }
    
        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;
        }
    }
    

    2.配置applicationContext.xml文件

    <!--构造注入-->
        <bean id="dao" class="cn.happy.day03aop.aop.Student">
            <!--index 0 代表构造中的第一个参数,须与构造中的参数类型保持一致-->
            <constructor-arg index="0" value="小张"></constructor-arg>
            <constructor-arg index="1" value="18"></constructor-arg>
        </bean>
    

    3.编写测试类

     @Test
        public void SpringStructure(){
            ApplicationContext ctx=new ClassPathXmlApplicationContext("applicationContext-day04di.xml");
            Student service=(Student)ctx.getBean("dao");
            System.out.println( service.getName()+"
    "+service.getAge());
        }
    

    4.查看测试结果

    p命名空间的注入

    使用前要先要在applicationContext.xml配置文件中引入p命名空间
    xmlns:p="http://www.springframework.org/schema/p"

    1.1创建一个Car类

    public class Car {
        private String color;
    
        public String getColor() {
            return color;
        }
    
        public void setColor(String color) {
            this.color = color;
        }
    }
    

    1.2在Student类中加入一个Car类型的car属性,并封装

    2.配置applicationContext.xml

    <!--命名空间p注入-->
        <bean id="car" class="cn.happy.day03aop.aop.Car">
            <property name="color" value="red"/>
        </bean>
    
        <bean id="service" class="cn.happy.day03aop.aop.Student" p:name="小王" p:age="20" p:car-ref="car"></bean>
    

    3.查看测试结果

    集合属性注入

    1.创建Mycollection类

    package cn.happy.day03aop.aop;
    
    import java.util.*;
    
    /**
     * Created by Administrator on 2018/3/5.
     */
    //集合属性注入
    public class Mycollection {
        private String[] array;
        private List<String> list;
        private Set<String> set;
        private Map<String,String> map;
        private Properties properties;
    
        @Override
        public String toString() {
            return "Mycollection{" +
                    "array=" + Arrays.toString(array) +
                    ", list=" + list +
                    ", set=" + set +
                    ", map=" + map +
                    ", properties=" + properties +
                    '}';
        }
    
        public String[] getArray() {
            return array;
        }
    
        public void setArray(String[] array) {
            this.array = array;
        }
    
        public List<String> getList() {
            return list;
        }
    
        public void setList(List<String> list) {
            this.list = list;
        }
    
        public Set<String> getSet() {
            return set;
        }
    
        public void setSet(Set<String> set) {
            this.set = set;
        }
    
        public Map<String, String> getMap() {
            return map;
        }
    
        public void setMap(Map<String, String> map) {
            this.map = map;
        }
    
        public Properties getProperties() {
            return properties;
        }
    
        public void setProperties(Properties properties) {
            this.properties = properties;
        }
    }

    2.配置applicationContext.xml

    <!--集合属性注入-->
        <bean id="collection" class="cn.happy.day03aop.aop.Mycollection" >
            <!--数组-->
            <property name="array">
                <array>
                    <value>小李</value>
                    <value>小王</value>
                </array>
            </property>
            <!--集合List-->
            <property name="list">
                <list>
                    <value>小张</value>
                    <value>小黄</value>
                </list>
            </property>
            <!--集合Set-->
            <property name="set">
                <set>
                    <value>小赵</value>
                    <value>小辉</value>
                </set>
            </property>
            <!--集合Map-->
            <property name="map">
                <map>
                   <entry key="Y2167" value="青鸟杯"></entry>
                    <entry key="Y2166" value="面试题"></entry>
                </map>
            </property>
            <!--集合Properties-->
            <property name="properties">
                <props>
                    <prop key="prop1">1</prop>
                    <prop key="prop2">2</prop>
                </props>
            </property>
        </bean>
    

    3.测试

     分享完毕

     

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  • 原文地址:https://www.cnblogs.com/xuchangqi1/p/8510975.html
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