Spring依赖注入详解-优快云博客

<?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">


    <bean id="pojo" class="di.Pojo"/>

    <!-- setter注入，必须提供对应属性的set方法-->
    <bean id="d1" class="di.DiTest">
        <property name="age" value="18"/>
        <property name="name" value="mika"/>
        <property name="pojo" ref="pojo"/>
        <property name="list">
            <list value-type="java.lang.Integer">
                <value>1</value>
                <value>2</value>
                <value>3</value>
            </list>
        </property>
        <property name="map">
            <map key-type="java.lang.Integer" value-type="java.lang.String">
                <entry key="1" value="a"/>
                <entry key="2" value="b"/>
                <entry key="3" value="c"/>
            </map>
        </property>
    </bean>


    <!--无参构造方法注入-->
    <bean id="d2" class="di.DiTest"/>

    <!--有参构造方法注入，可以使用参数名称或使用参数下标进行对应，或混用，参数个数对应不同有参构造，相同个数的构造根据参数类型进行对应  -->
    <bean id="d3" class="di.DiTest">
        <!-- type默认为String，建议指明类型 -->
        <constructor-arg name="age" type="int" value="18"/>
        <constructor-arg name="name" type="java.lang.String" value="mika"/>
        <constructor-arg index="2" type="di.Pojo" ref="pojo"/>
    </bean>

</beans>

package di;

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

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author LiFeng
 * @create 2021-03-09 10:13
 * @describe
 */
public class DiTest {

    private int age;
    private String name;
    private Pojo pojo;
    private List<Integer> list = new ArrayList<>();
    private Map<Integer, String> map = new HashMap<>();

    DiTest() {}

    DiTest(int age) {
        this.age = age;
    }

    DiTest(int age, String name) {
        this.age = age;
        this.name = name;
    }

    public DiTest(int age, String name, Pojo pojo) {
        this.age = age;
        this.name = name;
        this.pojo = pojo;
    }

    @Override
    public String toString() {
        return "DiTest{" +
                "age=" + age +
                ", name='" + name + '\'' +
                ", pojo=" + pojo +
                ", list=" + list +
                ", map=" + map +
                '}';
    }

    public List<Integer> getList() {
        return list;
    }

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

    public Map<Integer, String> getMap() {
        return map;
    }

    public void setMap(Map<Integer, String> map) {
        this.map = map;
    }

    public int getAge() {
        return age;
    }

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

    public String getName() {
        return name;
    }

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

    public Pojo getPojo() {
        return pojo;
    }

    public void setPojo(Pojo pojo) {
        this.pojo = pojo;
    }

    public static void main(String[] args) {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");

        DiTest di1 = (DiTest)applicationContext.getBean("d1");
        System.out.println(di1);
        DiTest di2 = (DiTest)applicationContext.getBean("d2");
        System.out.println(di2);
        DiTest di3 = (DiTest)applicationContext.getBean("d3");
        System.out.println(di3);
    }

}

package di;

/**
 * @author LiFeng
 * @create 2021-03-09 16:00
 * @describe
 */
public class Pojo {


}

结果如下

DiTest{age=18, name='mika', pojo=di.Pojo@56aac163, list=[1, 2, 3], map={1=a, 2=b, 3=c}}
DiTest{age=0, name='null', pojo=null, list=[], map={}}
DiTest{age=18, name='mika', pojo=di.Pojo@56aac163, list=[], map={}}