搭建一個超級簡單的spring框架


1.前期准備

(1)首先下載所需要的jar包

下載地址:
spring-framework-4.0.4.RELEASE-dist:http://repo.springsource.org/libs-release-local/org/springframework/spring/4.0.4.RELEASE/
commons-logging-1.1.3-bin:http://commons.apache.org
其他諸如log4j之類的並不是必須下載的。
如果下載速度慢可以在國內網站下載。
附:
spring-4.3.13-all:
鏈接:https://pan.baidu.com/s/1tUUzKOkVLbkJD7jZukM1hg 提取碼:v2zc
commons-logging-1.2-bin:
鏈接:https://pan.baidu.com/s/1CdYp9ozTH-zVStaTw5WI1g 提取碼:1ixb
下載后獲得的jar包放在lib文件夾下面

(2)做一個測試類

實體類Person:

package com.demo;

public class Person {
	public String say(){
		return "說了一句話:哇哈哈哈哈~";
	}

}

測試類:

package com.demo;

import org.junit.Test;

public class Test01 {

	@Test
	public void test() {
		Person p =new Person();
		System.out.println(p.say());
	}

}

項目的文件結構如下

2.spring的最簡單的應用

在上圖位置新建一個applicationContext.xml文件
內容如下:

<?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="person" class="com.demo.Person"></bean>
</beans>

之后在web.xml定義這個文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
	<display-name></display-name>
	<welcome-file-list>
		<welcome-file>index.jsp</welcome-file>
	</welcome-file-list>
	
	<context-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>classpath:resource/applicationContext.xml</param-value>
	</context-param>
	
</web-app>

做好聲明處理之后,就可以在測試類Test測試了,內容如下:

package com.demo;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Test01 {

	@Test
	public void test() {
		ApplicationContext ctx = new ClassPathXmlApplicationContext("resource/applicationContext.xml");
		Person p = (Person) ctx.getBean("person", Person.class);
		System.out.println(p.say());
	}

}

測試成功后,這樣,最簡單的spring框架就弄好了。

3.新建一個Servlet類

(1)具體步驟如下:


(2)新建完后的變化:


新建完,在web.xml會自動添加以下配置:

<servlet>
    <servlet-name>IndexServlet</servlet-name>
    <servlet-class>com.servlet.IndexServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>IndexServlet</servlet-name>
    <url-pattern>/IndexServlet</url-pattern>
  </servlet-mapping>

(3)測試代碼

在IndexServlet類下,修改如下代碼:

public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
		ApplicationContext ctx = new ClassPathXmlApplicationContext("resource/applicationContext.xml");
		Person p = (Person) ctx.getBean("person", Person.class);
		
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html");
		PrintWriter out = response.getWriter();
		out.println("<html><head><title>一二零叄的網站</title></head><body>");
		out.print(p.say()+"</body></html>");
		
	}

這時候輸入地址,就會出現想要的結果:

4.用注釋注入依賴

(1)准備工作:需要導入的一個包:

spring-aop-4.3.13.RELEASE.jar

(2)准備工作:導完包后修改一下配置文件

配置信息如下:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context"
	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
          http://www.springframework.org/schema/context 
          http://www.springframework.org/schema/context/spring-context.xsd">
          
      <context:component-scan base-package="com.entity"></context:component-scan>
      
      <bean id="person1" class="com.entity.Person"></bean>
    
</beans>

備注:
開啟注解掃描有兩種配置:

<context:component-scan base-package= ""/>
<context:annotation-config/>

區別是:
a.兩種配置都能開啟注解掃描,這樣就可以使用@Component、@Autowired這些注解了。
b.<context:component-scan base-package= “”/>會到指定包(包括指定包下的所有子包)中掃描類、方法、屬性上面是否有注解。(如有多個,可使用逗號分隔)
<context:annotation-config></context:annotation-config>這個配置只掃描屬性上是否有注解,所以一般不用寫。

(3)使用注釋注入依賴

package com.entity;

import org.springframework.stereotype.Component;

@Component("person2")
public class Person {
	
	private String username;
	private int sex;
	
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public int getSex() {
		return sex;
	}
	public void setSex(int sex) {
		this.sex = sex;
	}
	public String say(){
		return "說了一句話:哇哈哈哈哈~";
	}
	
}

調用:

public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
		ApplicationContext ctx = new ClassPathXmlApplicationContext("resource/applicationContext.xml");
		Person p1 = (Person) ctx.getBean("person1");
		p1.setUsername("張三");
		Person p2 = (Person) ctx.getBean("person2");
		p2.setUsername("李四");
		
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html");
		PrintWriter out = response.getWriter();
		out.println("<html><head><title>一二零叄的網站</title></head><body>");
		out.print(p1.getUsername() + p1.say()+"<br/>");
		out.print(p2.getUsername() + p2.say());
		out.print("</body></html>");
		
	}

結果:

這樣,使用xml配置文件和使用注釋來注入依賴就都可以實現了
備注:
Spring容器有三種方式配置Bean:
1、基於xml配置Bean
2、使用注解定義Bean
(@Component、@Controller、@Service、@Repository)
3、基於javaConfig提供Bean定義信息(@Configuration、@Bean)

5.AOP應用

(1)下載所需要的包

aspectj 1.8.10:http://mvnrepository.com/artifact/org.aspectj/aspectjrt/1.8.10
aspectjweaver 1.8.10:http://mvnrepository.com/artifact/org.aspectj/aspectjweaver/1.8.10
aopalliance 1.0:http://mvnrepository.com/artifact/aopalliance/aopalliance/1.0
附:
aopalliance、aspectjrt、aspectjweaver:
鏈接:https://pan.baidu.com/s/1rp6erh5WUVZsUymsO2b6Ow 提取碼:lm7x

(2)新建一個通知類:

package com.service;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;

public class MyAdvice {
	public void beforeMethod(JoinPoint joinpoint) {
		System.out.println("前置通知---");
	}

	public void afterMethod(JoinPoint joinpoint) {
		System.out.println("后置通知---");
	}

	public void afterReturnning(JoinPoint joinpoint, Object result) {
		System.out.println("返回通知---");
	}

	public void afterThrowing(JoinPoint joinpoint, Exception ex) {
		System.out.println("【異常通知】---" + joinpoint.toString());
	}

	public Object aroundMethod(ProceedingJoinPoint pjp) {
		Object obj = null;
		try {
			System.out.println("環繞通知---");
			long start = System.currentTimeMillis();
			obj = pjp.proceed(); // 執行目標方法
			long end = System.currentTimeMillis();
			System.out.println("環繞通知結束---方法執行時間:" + (end - start));
		} catch (Throwable e) {
			e.printStackTrace();
		}
		return obj;
	}
}

注:
JoinPoint:連接點(切入點)的連接對象,通過它可以獲取目標對象中的信息。
Object resuldt的參數名必須與配置文件中的<aop:after-returning returning="result"/>中的returning屬性的值一致。

(3)配置文件修改:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:aop="http://www.springframework.org/schema/aop"
	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
          http://www.springframework.org/schema/context 
          http://www.springframework.org/schema/context/spring-context.xsd
          http://www.springframework.org/schema/aop 
          http://www.springframework.org/schema/aop/spring-aop-4.1.xsd">

	<context:component-scan base-package="com.entity"></context:component-scan>

	<bean id="person1" class="com.entity.Person"></bean>
	<bean id="makePerson" class="com.service.MakePerson" />
	<bean id="myAdvice" class="com.service.MyAdvice" />

	<!-- aop的配置 -->
	<aop:config>
		<!-- 配置切入點 -->
		<!-- public * *(..) 表示所有public的方法 -->
		<aop:pointcut expression="execution(public * *(..))" id="pointcut" />
		<!-- 配置切面及切入的對象 -->
		<aop:aspect ref="myAdvice">
			<aop:before pointcut-ref="pointcut" method="beforeMethod" />
			<aop:after pointcut-ref="pointcut" method="afterMethod" />
			<aop:after-returning pointcut-ref="pointcut"
				method="afterReturnning" returning="result" />
			<aop:around pointcut-ref="pointcut" method="aroundMethod" />
			<aop:after-throwing pointcut-ref="pointcut"
				method="afterThrowing" throwing="ex" />
		</aop:aspect>
	</aop:config>

</beans>

(4)顯示界面修改

public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		
		ApplicationContext ctx = new ClassPathXmlApplicationContext("resource/applicationContext.xml");
		Person p1 = (Person) ctx.getBean("person1");
		p1.setUsername("張三");
		Person p2 = (Person) ctx.getBean("person2");
		p2.setUsername("李四");
		MakePerson p3 = (MakePerson) ctx.getBean("makePerson");
		
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html");
		PrintWriter out = response.getWriter();
		out.println("<html><head><title>一二零叄的網站</title></head><body>");
		out.print(p1.getUsername() + p1.say()+"<br/>");
		out.print(p2.getUsername() + p2.say()+"<br/>");
		out.print(p3.getNewPerson("王五"));
		out.print("</body></html>");
	}

(5)最終結果


后台顯示:

這樣,就能夠使用spring的注入依賴和面向切面技術了,一個很簡單的spring框架就搭好了。
附:
Spring PPT教程:
鏈接:https://pan.baidu.com/s/1T6ZJrb9Pbb2_Qmso72trIg 提取碼:x1sn


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