搭建一个超级简单的spring框架


1.前期准备

(1)首先下载所需要的jar包

下载地址:
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
其他诸如log4j之类的并不是必须下载的。
如果下载速度慢可以在国内网站下载。
附:
spring-4.3.13-all:
链接:https://pan.baidu.com/s/1tUUzKOkVLbkJD7jZukM1hg 提取码:v2zc
commons-logging-1.2-bin:
链接:https://pan.baidu.com/s/1CdYp9ozTH-zVStaTw5WI1g 提取码:1ixb
下载后获得的jar包放在lib文件夹下面

(2)做一个测试类

实体类Person:

package com.demo;

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

}

测试类:

package com.demo;

import org.junit.Test;

public class Test01 {

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

}

项目的文件结构如下

2.spring的最简单的应用

在上图位置新建一个applicationContext.xml文件
内容如下:

<?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定义这个文件

<?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>

做好声明处理之后,就可以在测试类Test测试了,内容如下:

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());
	}

}

测试成功后,这样,最简单的spring框架就弄好了。

3.新建一个Servlet类

(1)具体步骤如下:


(2)新建完后的变化:


新建完,在web.xml会自动添加以下配置:

<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)测试代码

在IndexServlet类下,修改如下代码:

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>一二零叁的网站</title></head><body>");
		out.print(p.say()+"</body></html>");
		
	}

这时候输入地址,就会出现想要的结果:

4.用注释注入依赖

(1)准备工作:需要导入的一个包:

spring-aop-4.3.13.RELEASE.jar

(2)准备工作:导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>

备注:
开启注解扫描有两种配置:

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

区别是:
a.两种配置都能开启注解扫描,这样就可以使用@Component、@Autowired这些注解了。
b.<context:component-scan base-package= “”/>会到指定包(包括指定包下的所有子包)中扫描类、方法、属性上面是否有注解。(如有多个,可使用逗号分隔)
<context:annotation-config></context:annotation-config>这个配置只扫描属性上是否有注解,所以一般不用写。

(3)使用注释注入依赖

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 "说了一句话:哇哈哈哈哈~";
	}
	
}

调用:

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("张三");
		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>一二零叁的网站</title></head><body>");
		out.print(p1.getUsername() + p1.say()+"<br/>");
		out.print(p2.getUsername() + p2.say());
		out.print("</body></html>");
		
	}

结果:

这样,使用xml配置文件和使用注释来注入依赖就都可以实现了
备注:
Spring容器有三种方式配置Bean:
1、基于xml配置Bean
2、使用注解定义Bean
(@Component、@Controller、@Service、@Repository)
3、基于javaConfig提供Bean定义信息(@Configuration、@Bean)

5.AOP应用

(1)下载所需要的包

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:
链接:https://pan.baidu.com/s/1rp6erh5WUVZsUymsO2b6Ow 提取码:lm7x

(2)新建一个通知类:

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("【异常通知】---" + joinpoint.toString());
	}

	public Object aroundMethod(ProceedingJoinPoint pjp) {
		Object obj = null;
		try {
			System.out.println("环绕通知---");
			long start = System.currentTimeMillis();
			obj = pjp.proceed(); // 执行目标方法
			long end = System.currentTimeMillis();
			System.out.println("环绕通知结束---方法执行时间:" + (end - start));
		} catch (Throwable e) {
			e.printStackTrace();
		}
		return obj;
	}
}

注:
JoinPoint:连接点(切入点)的连接对象,通过它可以获取目标对象中的信息。
Object resuldt的参数名必须与配置文件中的<aop:after-returning returning="result"/>中的returning属性的值一致。

(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>
		<!-- 配置切入点 -->
		<!-- public * *(..) 表示所有public的方法 -->
		<aop:pointcut expression="execution(public * *(..))" id="pointcut" />
		<!-- 配置切面及切入的对象 -->
		<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)显示界面修改

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("张三");
		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>一二零叁的网站</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)最终结果


后台显示:

这样,就能够使用spring的注入依赖和面向切面技术了,一个很简单的spring框架就搭好了。
附:
Spring PPT教程:
链接:https://pan.baidu.com/s/1T6ZJrb9Pbb2_Qmso72trIg 提取码:x1sn


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