Spring 注入集合
1. 介绍¶
你已经看到了如何使用 value 属性来配置基本数据类型和在你的 bean 配置文件中使用
现在如果你想传递多个值，如 Java Collection 类型 List、Set、Map 和 Properties，应该怎么做呢。为了处理这种情况，Spring 提供了四种类型的集合的配置元素，如下所示：
| 元素 | 描述 |
|---|---|
| <list> | 它有助于连线，如注入一列值，允许重复。 |
| <set> | 它有助于连线一组值，但不能重复。 |
| <map> | 它可以用来注入名称-值对的集合，其中名称和值可以是任何类型。 |
| <props> | 它可以用来注入名称-值对的集合，其中名称和值都是字符串类型。 |
你可以使用或
你会遇到两种情况（a）传递集合中直接的值（b）传递一个 bean 的引用作为集合的元素。
<!--给复杂类型进行赋值-->
<bean id="person9" class="com.cmz.bean.Nperson">
<property name="id" value="9"></property>
<property name="name" value="李9"></property>
<property name="age" value="29"></property>
<property name="gender" value="男"></property>
<property name="date" value="2020/02/28"></property>
<!--给数组赋值-->
<!--<property name="hobbies" value="book,girl,movie"></property>-->
<property name="hobbies">
<array>
<value>book</value>
<value>girl</value>
<value>movie</value>
</array>
</property>
<!--给引用类型赋值 可以使用ref引用外部bean-->
<property name="address" ref="address"></property>
<!--给list赋值-->
<!--写法1-->
<!--<property name="lists" value="1,2,3"></property>-->
<!--写法2-->
<property name="lists">
<list>
<!--使用内部bean 无非从IOC容器中直接获取对象的值-->
<bean class="com.cmz.bean.Address">
<property name="province" value="江苏省"></property>
<property name="city" value="南京市"></property>
<property name="town" value="下关"></property>
</bean>
<bean class="com.cmz.bean.Address">
<property name="province" value="河北省"></property>
<property name="city" value="北京市"></property>
<property name="town" value="朝阳大街"></property>
</bean>
<!--使用外部bean 可以随意从IOC容器获取对象的值-->
<ref bean="address"></ref>
</list>
</property>
<!--给set赋值-->
<property name="sets">
<set>
<value>张三</value>
<value>张三</value>
<value>李四</value>
<value>王五</value>
<value>赵六</value>
<value>陈七</value>
</set>
</property>
<!--给map赋值-->
<property name="maps">
<map>
<entry key="a" value="aaa"></entry>
<entry key="address" value-ref="address"></entry>
<entry key="address2">
<bean id="address2" class="com.cmz.bean.Address">
<property name="province" value="广东省"></property>
</bean>
</entry>
<entry>
<key>
<value>my_key</value>
</key>
<value>my_value</value>
</entry>
<entry key="list">
<list>
<value>11</value>
<value>22</value>
</list>
</entry>
</map>
</property>
<!--给properties赋值-->
<property name="properties">
<props>
<prop key="111">aaa</prop>
<prop key="222">bbb</prop>
<prop key="333">ccc</prop>
</props>
</property>
</bean>
2. 示例¶
ioc1.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="person" class="com.cmz.bean.Person">
<property name="id" value="1"></property>
<property name="name" value="张三"></property>
<property name="age" value="20"></property>
<property name="gender" value="男"></property>
<property name="date" value="2020/02/28"></property>
</bean>
<!--给复杂类型进行赋值-->
<bean id="person9" class="com.cmz.bean.Nperson">
<property name="id" value="9"></property>
<property name="name" value="李9"></property>
<property name="age" value="29"></property>
<property name="gender" value="男"></property>
<property name="date" value="2020/02/28"></property>
<!--给数组赋值-->
<!--<property name="hobbies" value="book,girl,movie"></property>-->
<property name="hobbies">
<array>
<value>book</value>
<value>girl</value>
<value>movie</value>
</array>
</property>
<!--给引用类型赋值 可以使用ref引用外部bean-->
<property name="address" ref="address"></property>
<!--给list赋值-->
<!--写法1-->
<!--<property name="lists" value="1,2,3"></property>-->
<!--写法2-->
<property name="lists">
<list>
<!--使用内部bean 无非从IOC容器中直接获取对象的值-->
<bean class="com.cmz.bean.Address">
<property name="province" value="江苏省"></property>
<property name="city" value="南京市"></property>
<property name="town" value="下关"></property>
</bean>
<bean class="com.cmz.bean.Address">
<property name="province" value="河北省"></property>
<property name="city" value="北京市"></property>
<property name="town" value="朝阳大街"></property>
</bean>
<!--使用外部bean 可以随意从IOC容器获取对象的值-->
<ref bean="address"></ref>
</list>
</property>
<!--给set赋值-->
<property name="sets">
<set>
<value>张三</value>
<value>张三</value>
<value>李四</value>
<value>王五</value>
<value>赵六</value>
<value>陈七</value>
</set>
</property>
<!--给map赋值-->
<property name="maps">
<map>
<entry key="a" value="aaa"></entry>
<entry key="address" value-ref="address"></entry>
<entry key="address2">
<bean id="address2" class="com.cmz.bean.Address">
<property name="province" value="广东省"></property>
</bean>
</entry>
<entry>
<key>
<value>my_key</value>
</key>
<value>my_value</value>
</entry>
<entry key="list">
<list>
<value>11</value>
<value>22</value>
</list>
</entry>
</map>
</property>
<!--给properties赋值-->
<property name="properties">
<props>
<prop key="111">aaa</prop>
<prop key="222">bbb</prop>
<prop key="333">ccc</prop>
</props>
</property>
</bean>
<bean id="address" class="com.cmz.bean.Address">
<property name="province" value="江苏省"></property>
<property name="city" value="宿迁市"></property>
<property name="town" value="来龙镇"></property>
</bean>
<!--bean之间的继承关系-->
<!--可以使用abstract标签定义抽象bean，无法进行实例化【abstract="true"】-->
<bean id="parent" class="com.cmz.bean.Nperson" abstract="false">
<property name="id" value="1"></property>
<property name="name" value="张三"></property>
<property name="age" value="20"></property>
<property name="gender" value="男"></property>
<property name="date" value="2020/02/28"></property>
</bean>
<!--可以通过parent属性来获取父bean中的某些属性值-->
<bean id="son" class="com.cmz.bean.Nperson" parent="parent">
<property name="name" value="儿子"></property>
</bean>
<!--创建bean的时候依赖关系
当bean对象被创建的时候，是按照xml配置文件定义的顺序创建的
谁在前就先被创建，如果需要干扰创建顺序，就使用depend-on属性
一般不用在意bean创建的顺序，无论谁先创建，需要依赖的对象在创建完成之后都会进行赋值
-->
<bean id="adress10" class="com.cmz.bean.Address"></bean>
<bean id="person10" class="com.cmz.bean.Nperson"></bean>
<bean id="adress11" class="com.cmz.bean.Address" depends-on="person11"></bean>
<bean id="person11" class="com.cmz.bean.Nperson"></bean>
</beans>
Nperson.class
package com.cmz.bean;
import java.util.*;
/**
* @author summer
* @create 2020-02-22 20:58
*/
public class Nperson{
private int id;
private String name;
private Integer age;
private String gender;
private Date date;
private String[] hobbies;
private Address address;
private List<Address> lists;
private Set<String> sets;
private Map<String,Object> maps;
private Properties properties;
public Nperson() {
System.out.println("Nperson 被创建");
}
public Nperson(int id, String name, Integer age, String gender, Date date, String[] hobbies, Address address, List<Address> lists, Set<String> sets, Map<String, Object> maps, Properties properties) {
this.id = id;
this.name = name;
this.age = age;
this.gender = gender;
this.date = date;
this.hobbies = hobbies;
this.address = address;
this.lists = lists;
this.sets = sets;
this.maps = maps;
this.properties = properties;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
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 String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public Date getDate() {
return date;
}
public void setDate(Date date) {
this.date = date;
}
public String[] getHobbies() {
return hobbies;
}
public void setHobbies(String[] hobbies) {
this.hobbies = hobbies;
}
public Address getAddress() {
return address;
}
public void setAddress(Address address) {
this.address = address;
}
public List<Address> getLists() {
return lists;
}
public void setLists(List<Address> lists) {
this.lists = lists;
}
public Set<String> getSets() {
return sets;
}
public void setSets(Set<String> sets) {
this.sets = sets;
}
public Map<String, Object> getMaps() {
return maps;
}
public void setMaps(Map<String, Object> maps) {
this.maps = maps;
}
public Properties getProperties() {
return properties;
}
public void setProperties(Properties properties) {
this.properties = properties;
}
@Override
public String toString() {
return "Person{" +
"id=" + id +
", name='" + name + '\'' +
", age=" + age +
", gender='" + gender + '\'' +
", date=" + date +
", hobbies=" + Arrays.toString(hobbies) +
", address=" + address +
", lists=" + lists +
", sets=" + sets +
", maps=" + maps +
", properties=" + properties +
'}';
}
}
Address.class
package com.cmz.bean;
/**
* @author summer
* @create 2020-02-28 18:24
*/
public class Address {
private String province;
private String city;
private String town;
public Address() {
System.out.println("Address 被创建");
}
public Address(String province, String city, String town) {
this.province = province;
this.city = city;
this.town = town;
}
public String getProvince() {
return province;
}
public void setProvince(String province) {
this.province = province;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getTown() {
return town;
}
public void setTown(String town) {
this.town = town;
}
@Override
public String toString() {
return "Address{" +
"province='" + province + '\'' +
", city='" + city + '\'' +
", town='" + town + '\'' +
'}';
}
}
MyTest1.class
import com.cmz.bean.Nperson;
import com.cmz.bean.Person;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
* @author summer
* @create 2020-02-22 21:06
*/
public class MyTest1 {
public static void main(String[] args) {
ApplicationContext context9 = new ClassPathXmlApplicationContext("ioc1.xml");
Nperson person9 = context9.getBean("person9", Nperson.class);
System.out.println(person9);
}
}
输出[稍微格式化了一下]
Person {
id = 9, name = '李9', age = 29, gender = '男', date = Fri Feb 28 00: 00: 00 CST 2020, hobbies = [book, girl, movie], address = Address {
province = '江苏省', city = '宿迁市', town = '来龙镇'
}, lists = [Address {
province = '江苏省', city = '南京市', town = '下关'
}, Address {
province = '河北省', city = '北京市', town = '朝阳大街'
}, Address {
province = '江苏省', city = '宿迁市', town = '来龙镇'
}], sets = [张三, 李四, 王五, 赵六, 陈七], maps = {
a = aaa,
address = Address {
province = '江苏省', city = '宿迁市', town = '来龙镇'
},
address2 = Address {
province = '广东省', city = 'null', town = 'null'
},
my_key = my_value,
list = [11, 22]
}, properties = {
333 = ccc,
222 = bbb,
111 = aaa
}
}