spring bean 配置

在spring的xml配置文件中咱們能夠經過<bean>標籤 進行java bean的注入

基礎注入

基礎bean類

package com.zhu.example.beantest;

/**
 * <p>Title: HelloWorldBean</p>
 * <p>Description: </p>
 * @author zhukai
 */
public class HelloWorldBean {
	private String messageString="Hello World";
	
	HelloWorldBean(){
		
	}
	
	HelloWorldBean(String message){
		this.messageString=message;
	}

	public String getMessageString() {
		return messageString;
	}

	public void setMessageString(String messageString) {
		this.messageString = messageString;
	}
	
	
}

xml文件bean配置

<!-- 最基礎的bean配置 -->
     <bean id="HelloWorldBean" class="com.zhu.example.beantest.HelloWorldBean" ></bean>

這種bean注入採用的是注入類的無參數構造函數進行類的實例化，而且是單例模式的

多實例注入

<!-- 多實例模式 每次getbean有一個新的實例生成-->
     <bean id="mutiHelloWorldBean" class="com.zhu.example.beantest.HelloWorldBean" scope="prototype"></bean>

針對web應用程序，還能夠配置爲request、session等範圍。

帶參數的構造函數的bean注入

注入類

package com.zhu.example.beantest;

import java.util.Date;

/**
 * <p>Title: ParamConstructorBean</p>
 * <p>Description:這個類沒有空方法 </p>
 * @author zhukai
 */
public class ParamConstructorBean {
	
	private String name;
	
	private Date  date;
	
	ParamConstructorBean(String name){
		this.name=name;
	}
	
	ParamConstructorBean(Date date){
		this.date=date;
	}

	public String getName() {
		return name;
	}

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

	public Date getDate() {
		return date;
	}

	public void setDate(Date date) {
		this.date = date;
	}

	
}

這個類有兩個構造函數。

xml文件配置

<!-- 帶參數的構造函數 -->
	<bean id="ParamConstructorBean" class="com.zhu.example.beantest.ParamConstructorBean">
		<constructor-arg>
			<value>hello</value>
		</constructor-arg>
	</bean>

這個注入使用的構造函數是 String 類型爲參數的

<!-- 帶參數的構造函數(參數爲一個bean) -->
	<bean id="bean_date" class="java.util.Date" /> 


	<bean id="ParamConstructorBean" class="com.zhu.example.beantest.ParamConstructorBean">
		<constructor-arg index="0" ref="bean_date">
		</constructor-arg>
	</bean>

這個注入 使用構造函數參數爲date的

工廠模式注入

使用靜態工廠和實例工廠，兩種工廠來注入HelloWorldBean類

靜態工廠

package com.zhu.example.beantest;

/**
 * <p>Title: StaticBeanFactory</p>
 * <p>Description: </p>
 * @author zhukai
 */
public class StaticBeanFactory {
	
	public static HelloWorldBean getHelloBean() {
		
		return new HelloWorldBean("sta hello world");
	}

}

實例工廠

package com.zhu.example.beantest;

/**
 * <p>Title: InstanceBeanFactory</p>
 * <p>Description: </p>
 * @author zhukai
 */
public class InstanceBeanFactory {
	
	public HelloWorldBean getHelloBean() {
		return new HelloWorldBean("ins hello world");
	}
}

xml文件配置

<!-- 工廠模式配置bean -->
	<!-- 靜態工廠 -->
	<bean id="HelloWorldBeanfac" class="com.zhu.example.beantest.StaticBeanFactory" factory-method="getHelloBean"/> 
	
	<!-- 實例工廠 -->
	<bean id="bean_factory" class="com.zhu.example.beantest.InstanceBeanFactory"/> 

	<bean id="HelloWorldBeanfacIns" factory-bean="bean_factory" factory-method="getHelloBean"/>

bean property 注入

<!-- 屬性注入 -->
    <bean id="HelloWorldBeanPro" class="com.zhu.example.beantest.HelloWorldBean" >
    	    <property name="messageString" value="pro 測試 你好！" /> 
    </bean>

只要實現了相似這種get、set方法就等實現成員變量的注入

public String getMessageString() {
		return messageString;
	}

	public void setMessageString(String messageString) {
		this.messageString = messageString;
	}

注入完成後的bean取用

首先初始化context

@Before
	public void setUp() throws Exception {
		context = new ClassPathXmlApplicationContext(new String[]{"classpath:applicationContext.xml","applicationContext-beantest.xml"});

	}

測試類

@Test
	public void testRegBean() throws Exception {
		//基礎bean
		HelloWorldBean basicHelloBean = (HelloWorldBean) context.getBean("HelloWorldBean");
		
		//基礎帶參數構造函數bean
		ParamConstructorBean basicParamBean = (ParamConstructorBean) context.getBean("ParamConstructorBean");
		
		//靜態工廠模式bean
		HelloWorldBean facHelloBean = (HelloWorldBean) context.getBean("HelloWorldBeanfac");
		
		//實例工廠模式bean
		HelloWorldBean facInsHelloBean = (HelloWorldBean) context.getBean("HelloWorldBeanfacIns");
		
		
		
		System.out.println(basicHelloBean.getMessageString());
		System.out.println(basicParamBean.getDate());
		System.out.println(facHelloBean.getMessageString());
		System.out.println(facInsHelloBean.getMessageString());
		
		
	}

輸出以下

Hello World
Thu Aug 11 11:11:04 CST 2016
sta hello world
ins hello world