Spring的属性注入
注入方式
1. set方法注入(!!!)
新建Car.java
com/eilas/c_injection/applicationContext.xml
bean对象使用ref (reference引用),普通类型使用value
<?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">
<!-- set方式注入: -->
<bean name="user" class="com.eilas.bean.User" >
<!--值类型注入: 为User对象中名为name的属性注入tom作为值 -->
<property name="name" value="tom" ></property>
<property name="age" value="18" ></property>
<property name="car" ref="car"></property>
<!-- 引用类型注入: 为car属性注入下方配置的car对象 -->
</bean>
<!-- 将car对象配置到容器中 -->
<bean name="car" class="com.eilas.bean.Car" >
<property name="name" value="兰博基尼" ></property>
<property name="color" value="黄色" ></property>
</bean>
</beans>
Test_injection.java
package com.eilas.c_injection;
import com.eilas.bean.User;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Test_injection {
@Test
public void test01() {
ApplicationContext context = new ClassPathXmlApplicationContext("com/eilas/c_injection/applicationContext.xml");
User user = (User) context.getBean("user");
System.out.println(user);
}
}
result
2. 构造函数注入
com/eilas/c_injection/applicationContext.xml
<!-- 构造函数注入 -->
<!-- name属性: 构造函数的参数名 -->
<!-- index属性: 构造函数的参数索引 -->
<!-- type属性: 构造函数的参数类型-->
<bean name="user2" class="com.eilas.bean.User">
<constructor-arg name="name" value="111" index="0" type="java.lang.Integer"></constructor-arg>
<constructor-arg name="car" ref="car" index="1"></constructor-arg>
</bean>
User.java
public User() {
System.out.println("空参数构造方法");
}
public User(String name, Car car) {
System.out.println("User(String name, Car car)!!");
this.name = name;
this.car = car;
}
public User(Car car,String name) {
System.out.println("User(Car car,String name)!!");
this.name = name;
this.car = car;
}
public User(Integer name, Car car) {
System.out.println("User(Integer name, Car car)!!");
this.name = name+"";
this.car = car;
}
Test_injection.java
@Test
public void test02() {
ApplicationContext context = new ClassPathXmlApplicationContext("com/eilas/c_injection/applicationContext.xml");
User user = (User) context.getBean("user2");
System.out.println(user);
}
result:
3.p名称空间注入
p名称空间注入, 走set方法
1.导入P名称空间 xmlns:p=“http://www.springframework.org/schema/p”
2.使用p:属性完成注入
|-值类型: p:属性名=“值”
|-对象类型: p:属性名-ref=“bean名称”
.xml
<!-- p名称空间注入, 走set方法
1.导入P名称空间 xmlns:p="http://www.springframework.org/schema/p"
2.使用p:属性完成注入
|-值类型: p:属性名="值"
|-对象类型: p:属性名-ref="bean名称" -->
<bean name="user3" class="com.eilas.bean.User" p:name="jack" p:age="20" p:car-ref="car">
</bean>
Test_injection.java
@Test
public void test03() {
ApplicationContext context = new ClassPathXmlApplicationContext("com/eilas/c_injection/applicationContext.xml");
User user = (User) context.getBean("user3");
System.out.println(user);
}
4. spel注入
.xml
<!--
spel注入: spring Expression Language sping表达式语言
使用已有bean的属性
-->
<bean name="user4" class="com.eilas.bean.User">
<property name="name" value="#{user.name}"></property>
<property name="age" value="#{user3.age}"></property>
<property name="car" ref="car"></property>
</bean>
Test_injection.java
@Test
public void test04() {
ApplicationContext context = new ClassPathXmlApplicationContext("com/eilas/c_injection/applicationContext.xml");
User user = (User) context.getBean("user4");
System.out.println(user);
}
复杂类型注入
新建类CollectionBean.java
package com.eilas.c_injection;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Properties;
public class CollectionBean {
private Object[] arr;//数组
private List list; //list/set
private Map map;//map类型
private Properties prop; //properties(也是键值)
public Object[] getArr() {
return arr;
}
public void setArr(Object[] arr) {
this.arr = arr;
}
public List getList() {
return list;
}
public void setList(List list) {
this.list = list;
}
public Map getMap() {
return map;
}
public void setMap(Map map) {
this.map = map;
}
public Properties getProp() {
return prop;
}
public void setProp(Properties prop) {
this.prop = prop;
}
@Override
public String toString() {
return "CollectionBean{" +
"arr=" + Arrays.toString(arr) +
", list=" + list +
", map=" + map +
", prop=" + prop +
'}';
}
}
.xml
<!-- 复杂类型注入 -->
<bean name="cb" class="com.eilas.c_injection.CollectionBean">
<!-- array注入,单个元素注入 -->
<!-- 如果数组中只准备注入一个值(对象),直接使用value|ref即可-->
<!--<property name="arr" value="tom"></property>-->
<!-- array注入,多个元素注入 -->
<property name="arr">
<array>
<value>tom</value>
<value>jerry</value>
<ref bean="user4"></ref>
</array>
</property>
<!-- 如果List中只准备注入一个值(对象),直接使用value|ref即可
<property name="list" value="jack" ></property>-->
<property name="list">
<list>
<value>jack</value>
<value>rose</value>
<ref bean="user3"></ref>
</list>
</property>
<!-- map类型注入 -->
<property name="map">
<map>
<entry key="url" value="jdbc:mysql://localhost:3306?admin"></entry>
<entry key="driver" value="com.mysql.jdbc.Driver"></entry>
<entry key="user" value-ref="user4"></entry>
<entry key-ref="user3" value-ref="user2"></entry>
</map>
</property>
<!-- prperties 类型注入 -->
<property name="prop">
<props>
<prop key="driverClass">com.mysql.jdbc.Driver</prop>
<prop key="userName">admin</prop>
<prop key="password">123465</prop>
</props>
</property>
</bean>
Test_injection.java
@Test
public void test05() {
ApplicationContext context = new ClassPathXmlApplicationContext("com/eilas/c_injection/applicationContext.xml");
CollectionBean cb = (CollectionBean) context.getBean("cb");
System.out.println(cb);
}
result:
