Spring学习（1）--使用xml配置Bean属性

使用xml配置Bean属性之前需要先定义对应的XML和对应xsd文件：

<?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">

依赖注入主要有三种方式：

1.setter注入

2.构造器注入

3.接口注入

由于接口注入使用很少，这里主要写下前面两种注入属性的方式。

1.使用setter方式

Java文件代码：

package com.study.beans;

public class HelloWorld {
private String name;

public void setName(String name) {
System.out.println("setName()"+name);
this.name = name;
}
public HelloWorld(){
System.out.println("HelloWorld的无参构造器");
}
public void hello(){
System.out.println("hello"+name);
}

}

xml文件代码：

<!--setter方式属性注入  -->
<bean id="helloWorld" class="com.study.beans.HelloWorld">
<property name="name" value="zhang"></property>
</bean>

测试代码：

public class TestDemo {

@Test
public void test(){
//1.加载spring配置文件，根据配置创建对象
//ClassPathXmlApplicationContext是ApplicationContext接口的实现类，该类从类路径下加载配置文件
ApplicationContext app=new ClassPathXmlApplicationContext("applicationContext.xml");
//2.获取Bean
HelloWorld helloWorld=(HelloWorld) app.getBean("helloWorld");
System.out.println(helloWorld);
}
}

测试结果：

HelloWorld的无参构造器
setName()zhang

2.使用构造器方式
Java文件代码：

package com.study.beans;

public class CarDemo {
private String brand;
private String corp;
private double price;
private int maxSpeed;

public void setMaxSpeed(int maxSpeed) {
this.maxSpeed = maxSpeed;
}

public CarDemo(String brand, String corp, double price) {
super();
this.brand = brand;
this.corp = corp;
this.price = price;
}

public CarDemo(String brand, String corp, int maxSpeed) {
super();
this.brand = brand;
this.corp = corp;
this.maxSpeed = maxSpeed;
}

public CarDemo(String brand, String corp, double price, int maxSpeed) {
super();
this.brand = brand;
this.corp = corp;
this.price = price;
this.maxSpeed = maxSpeed;
}

@Override
public String toString() {
return "CarDemo [brand=" + brand + ", corp=" + corp + ", price="
+ price + ", maxSpeed=" + maxSpeed + "]";
}

}

xml文件代码：

<!--构造器方式属性注入  -->
<bean id="carDemo" class="com.study.beans.CarDemo">
<constructor-arg value="BMW"></constructor-arg>
<constructor-arg value="HEFEI"></constructor-arg>
<constructor-arg value="6900"></constructor-arg>
</bean>

3.属性值特殊字符的注入，如xml中的特殊字符"<"">"使用<!CDATA[xxx]>
xml文件代码：

<!--特殊字符可以使用<!CDATA[xxx]>方式注入  -->
<bean id="carDemo1" class="com.study.beans.CarDemo">
<constructor-arg  index="0" type="String">
<value><![CDATA[<DGDG>]]></value>
</constructor-arg>
<constructor-arg  index="1" type="String">
<value>822</value>
</constructor-arg>
<constructor-arg value="6900" index="2" type="int"></constructor-arg>
</bean>

测试结果：

CarDemo [brand=<DGDG>, corp=822, price=0.0, maxSpeed=6900]

4.null值的注入

<!-- null值使用<null/>注入 -->
<bean id="carDemo2" class="com.study.beans.CarDemo">
<constructor-arg value="Bmw" index="0" type="String"></constructor-arg>
<constructor-arg>
<null/>
</constructor-arg>
<constructor-arg >
<value>822.0</value>
</constructor-arg>
</bean>

5.使用ref引用其他Bean，引用的是其他Bean的id
java文件代码：

package com.study.beans;

public class Person {
private String name;
private int age;
private CarDemo car;

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

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

public String getName() {
return name;
}

public int getAge() {
return age;
}

public CarDemo getCar() {
return car;
}

public void setCar(CarDemo car) {
this.car = car;
}

public Person() {
}

public Person(String name, i
b155
nt age, CarDemo car) {
super();
this.name = name;
this.age = age;
this.car = car;
}

@Override
public String toString() {
return "Person [name=" + name + ", age=" + age + ", car=" + car + "]";
}
}

xml文件代码：

<!-- 使用ref引用其他Bean -->
<bean id="person1" class="com.study.beans.Person">
<property name="name" value="zhangshiwei"></property>
<property name="age" value="23"></property>
<property name="car" ref="carDemo2"></property>
</bean>

6.使用内部Bean

<!-- 内部Bean，只能在内部使用，不能被外部引用 -->
<bean id="person2" class="com.study.beans.Person">
<property name="name" value="zhangshiwei"></property>
<property name="age" value="23"></property>
<property name="car">
<bean class="com.study.beans.CarDemo">
<constructor-arg value="Bmw" index="0" type="String"></constructor-arg>
<constructor-arg><null/></constructor-arg>
<constructor-arg >
<value>822.0</value>
</constructor-arg>
</bean>
</property>
</bean>

7.为级联属性赋值

<!--为级联属性赋值  -->
<bean id="person3" class="com.study.beans.Person">
<constructor-arg name="name" value="zhangshiwei"></constructor-arg>
<constructor-arg name="age" value="23"></constructor-arg>
<constructor-arg name="car" ref="carDemo2"></constructor-arg>
<property name="car.maxSpeed" value="444"></property>
</bean>

上面代码中必须先初始化id为car的Bean，否则报错

8.为list集合属性赋值
将person类中的car属性改为：

public class PersonListCar {
private String name;
private int age;
private List<CarDemo> cars;

<!--为list集合属性赋值  -->
<bean id="personListCar" class="com.study.beans.PersonListCar">
<constructor-arg name="name" value="zhangshiwei"></constructor-arg>
<constructor-arg name="age" value="23"></constructor-arg>
<constructor-arg name="cars">
<list>
<ref bean="carDemo"/>
<ref bean="carDemo1"/>
<ref bean="carDemo2"/>
</list>
</constructor-arg>
</bean>

测试结果：

PersonListCar [name=zhangshiwei, age=23, cars=[CarDemo [brand=BMW, corp=HEFEI, price=0.0, maxSpeed=6900],
CarDemo [brand=<DGDG>, corp=822, price=0.0, maxSpeed=6900], CarDemo [brand=Bmw, corp=null, price=822.0, maxSpeed=444]]]

如上面代码所示<list>节点引用了其他Bean,若注入的值是基本数据类型,写法如下：

<list>
<value>list1</value>
<value>list2</value>
<value>list3</value>
</list>

set集合和数组类型的属性注入方式与list集合类似，区别在与list集合使用<list>节点，set集合使用<set>节点，数组使用<array>节点。

9.为Map类型属性赋值
将person类中的car属性改为：

public class PersonMapCar {
private String name;
private int age;
private Map<String,CarDemo> car;

<!--为Map类型属性赋值  -->
<bean id="personMapCar" class="com.study.beans.PersonMapCar">
<constructor-arg name="name" value="zhangshiwei"></constructor-arg>
<constructor-arg name="age" value="23"></constructor-arg>
<constructor-arg name="car">
<map>
<entry key="car1" value-ref="carDemo"/>
<entry key="car2" value-ref="carDemo1"/>
<entry key="car3" value-ref="carDemo2"/>
</map>
</constructor-arg>
</bean>

测试结果：

PersonMapCar [name=zhangshiwei, age=23, car={car1=CarDemo [brand=BMW, corp=HEFEI, price=0.0, maxSpeed=6900],
car2=CarDemo [brand=<DGDG>, corp=822, price=0.0, maxSpeed=6900], car3=CarDemo [brand=Bmw, corp=null, price=822.0, maxSpeed=444]}]

10.配置Properties类型属性值

Java文件代码：

package com.study.beans;

import java.util.Properties;

public class DataSource {
private Properties properties;

public Properties getProperties() {
return properties;
}

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

@Override
public String toString() {
return "DataSource [properties=" + properties + "]";
}

}

xml文件代码：

<!--配置Properties类型属性值  -->
<bean id="dataSource" class="com.study.beans.DataSource">
<property name="properties">
<props>
<prop key="user">root</prop>
<prop key="password">root</prop>
<prop key="jdbcUrl">jdbc:mysql:///test</prop>
<prop key="driverClass">com.mysql.jdbc.Driver</prop>
</props>
</property>
</bean>

测试结果：

DataSource [properties={driverClass=com.mysql.jdbc.Driver, user=root, password=root, jdbcUrl=jdbc:mysql:///test}]

11.使用util命名空间，配置独立的集合Bean,可供其他Bean引用

<!-- 使用util命名空间，配置独立的集合Bean,可供其他Bean引用 ，需要先引入util命名空间-->
<util:list id="car">
<ref bean="carDemo"/>
<ref bean="carDemo1"/>
<ref bean="carDemo2"/>
</util:list>
<bean id="personListCar1" class="com.study.beans.PersonListCar">
<constructor-arg name="name" value="zhangshiwei"></constructor-arg>
<constructor-arg name="age" value="23"></constructor-arg>
<constructor-arg name="cars" ref="car"></constructor-arg>
</bean>

引入的util命名空间：

xmlns:util="http://www.springframework.org/schema/util"
xsi:schemaLocation="http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd">[/code] 12.使用p命名空间为Bean的属性赋值

<!--使用p命名空间为Bean的属性赋值  ,需要先导入p命名空间-->
<bean id="personListCar2" class="com.study.beans.PersonListCar"
p:name="ZhangShiWei" p:age="23" p:cars-ref="car"></bean>
引入的p命名空间：

xmlns:p="http://www.springframework.org/schema/p"


13.使用c命名空间注入构造参数的属性

<!--使用c命名空间注入构造参数的属性 ,需要先导入c命名空间  -->
<bean id="personListCar3" class="com.study.beans.PersonListCar"
c:_0="ZHANGSHIwei" c:_1="23" c:_2-ref="car"></bean>


引入的c命名空间：

xmlns:c="http://www.springframework.org/schema/c"