您当前的位置： 首页 > 慢生活 > 程序人生 网站首页程序人生

17-Spring配置文件-依赖注入7（map、list、properties类型注入）

发布时间：2024-12-20 12:08:15编辑：雪饮阅读（）

上篇中主要是了解了通过Spring Config配置文件向类实例的普通属性注入值，那么其实也可以支持集合这种类型值的注入。
这里以List、Map、Properties为例。
首先我假定有一个User类
package com;

public class User {
    private String name;
    private String addr;

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

    public void setAddr(String addr) {
        this.addr = addr;
    }
    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", addr='" + addr + '\'' +
                '}';
    }
}
而我UserDao的实现中在map集合中map的key-val中的val部分就是该User对象实例
并且为了让List、Map、Properties能被注入，则需要实现setter方法，以及最后为了验证这3种类型数据的注入，则也需要打印这三种数据，所以在这里UserDao的实现如：
package com.dao.impl;

import com.User;
import com.dao.UserDao;

import java.util.List;
import java.util.Map;
import java.util.Properties;

public class UserDaoImpl implements UserDao {
    private int age;
    private String name;

    private List<String> strList;
    private Map<String, User> userMap;
    private Properties properties;

    public void setStrList(List<String> strList) {
        this.strList = strList;
    }

    public void setUserMap(Map<String, User> userMap) {
        this.userMap = userMap;
    }

    public void setProperties(Properties properties) {
        this.properties = properties;
    }




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

    public void setName(String name) {
        this.name = name;
    }
    public UserDaoImpl(){
        System.out.println("-----UserDaoImpl被创建--------");
    }
    public void save() {
        System.out.println("-----UserDaoImpl save: name:"+name+",age:"+age);
        System.out.println("-----UserDaoImpl save: strList:"+strList+",userMap:"+userMap+",properties:"+properties);
    }
    public void init(){
        System.out.println("执行了init方法");
    }
    public void destroy(){
        System.out.println("执行了destroy方法");
    }
}
那么对于map集合的注入，首先我们需要在Spring Config配置中定义key-val中val部分由于是User的实例，所以在Spring Config中需要先有User实例，这里也以bean定义为例手动定义。
用标签嵌套到bean中
对于list集合，property=>list=>value,这样三个标签。
map则是property=>map=>entry(key属性与value-ref
(因为这里key-val的val部分是User实例是引用)指向bean定义的User实例id)
properties则是property=》props(key属性)=》值
那么完整的Spring Config配置则如：
<?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="buser1" class="com.User">
                <property name="name" value="user1"></property>
                <property name="addr" value="shenzhen"></property>
        </bean>
        <bean id="buser2" class="com.User">
                <property name="name" value="user2"></property>
                <property name="addr" value="shanxi"></property>
        </bean>
        <bean id="userDao" class="com.dao.impl.UserDaoImpl">
                <property name="name" value="zhangsan"></property>
                <property name="age" value="18"></property>
                <property name="strList">
                        <list>
                                <value>a</value>
                                <value>b</value>
                                <value>c</value>
                        </list>
                </property>
                <property name="userMap">
                        <map>
                                <entry key="mp_user1" value-ref="buser1"></entry>
                                <entry key="mp_user2" value-ref="buser2"></entry>
                        </map>
                </property>
                <property name="properties">
                        <props>
                                <prop key="key1">val1</prop>
                                <prop key="key2">val2</prop>
                        </props>
                </property>
        </bean>
        <bean id="userService" class="com.service.impl.UserServiceImplement">
                <constructor-arg name="userDao" ref="userDao"></constructor-arg>
        </bean>
</beans>