Spring ： constructor-arg property 注入

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转载最新推荐文章于 2026-04-10 11:30:12 发布 718 阅读 AI 写同款· GEO 优化 ›

《Spring》第十一篇 DI手动注入之使用＜constructor-arg＞标签 1. 简述与样例 2. 源码解析 3. 构造参数注入时机 4. 装配过程 5. 属性精准映射赋值依赖注入属于Bean的生命周期的一个很重要的环节,大类可分为使用xml配置和使用注解定义的方式两大类, 也可分为手动注入和自动注入(现用的最多的方式) 本文重点介绍使用XML实现注入的构造函数注入方式,Spring源码版本是5.0 不管使用哪种方式实现注入,只要是使用了xml配置文件的方式,第一步都需要解析xml配置文件,解析的过程参见另一篇文章《Spring》第九篇 XML配置文件的解析过程 1. 简述阅读详情

1、说明

constructor-arg：通过构造函数注入。
property：通过setter对应的方法注入。

2、constructor-arg的使用示例

(1)、Model代码：

public class Student
 {

    private Integer
 id;

    private String
 name;

    private List<String>
 dream;

    private Map<String,
 Integer> score;

    private boolean graduation;

                                                                                                                                                                           

    public Student()
 {

                                                                                                                                                                           

    }

                                                                                                                                                                           

    public Student(Integer
 id, String name, List<String> dream,

            Map<String,
 Integer> score, boolean graduation)
 {

        this.id
 = id;

        this.name
 = name;

        this.dream
 = dream;

        this.score
 = score;

        this.graduation
 = graduation;

    }

                                                                                                                                                                           

    @Override

    public String
 toString() {

        return "Student
 [id=" +
 id + ",
 name=" +
 name + ",
 dream=" +
 dream

                + ",
 score=" +
 score + ",
 graduation=" +
 graduation + "]";

    }

                                                                                                                                                                           

}

(2)、xml配置：

<bean id="student" class="com.rc.sp.Student">

    <constructor-arg name="id" value="1"/>

    <constructor-arg name="name" value="student"/>

    <constructor-arg name="dream">

        <list>

            <value>soldier</value>

            <value>scientist</value>

            <value>pilot</value>

        </list>

    </constructor-arg>

    <constructor-arg name="score">

        <map>

            <entry key="math" value="90"/>

            <entry key="english" value="85"/>

        </map>

    </constructor-arg>

    <constructor-arg name="graduation" value="false"/>

</bean>

说明：<constructor-arg name="id" value="1"/>也可以改成<constructor-arg index="0" value="1"/>方式；boolean的值既可以用0/1填充，也可以用true/false填充。

3、property的使用示例

(1)、Model代码：

public class Teacher
 {

    private Integer
 id;

    private String
 name;

    public Integer
 getId() {

        return id;

    }

    public void setId(Integer
 id) {

        this.id
 = id;

    }

    public String
 getName() {

        return name;

    }

    public void setName(String
 name) {

        this.name
 = name;

    }

    @Override

    public String
 toString() {

        return "Teacher
 [id=" +
 id + ",
 name=" +
 name + "]";

    }

}

(2)、xml配置：

<bean id="teacher" class="com.rc.sp.Teacher">

    <property name="id" value="1"></property>

    <property name="name" value="teacher"></property>

</bean>

4、Test

(1)、测试代码：

public class Run
 {

    public static void main(String[]
 args) {

        ApplicationContext
 context = new ClassPathXmlApplicationContext(

                "applicationContext.xml");

        Student
 student = (Student) context.getBean("student");

        System.out.println(student);

        Teacher
 teacher = (Teacher) context.getBean("teacher");

        System.out.println(teacher);

    }

}