Spring

一 :什么是spring?


   Spring是一个开源框架,它由Rod Johnson创建。它是为了解决企业应用开发的复杂性而创建的。
   Spring使用基本的JavaBean来完成以前只可能由EJB完成的事情。
   然而,Spring的用途不仅限于服务器端的开发。从简单性、可测试性和松耦合的角度而言,任何Java应用都可以从Spring中受益。
   目的:解决企业应用开发的复杂性
   功能:使用基本的JavaBean代替EJB,并提供了更多的企业应用功能
   范围:任何Java应用
   简单来说,Spring是一个轻量级的控制反转(IoC)和面向切面(AOP)的容器框架。
   
2.中间层框架、万能胶
       struts2
       spring
       hibernate
  3.容器框架
         JavaBean    项目中的一个个类
         IOC和AOP

4.框架与框架之间需要整合:

5. spring包含的核心模块: 

 二: 什么是控制反转(依赖注入) 

  控制反转(IoC=Inversion of Control)IoC,用白话来讲,就是由容器控制程序之间的(依赖)关系,而非传统实现中,由程序代码直接操控。这也就是所谓“控制反转”的概念所在:(依赖)控制权由应用代码中转到了外部容器,控制权的转移,是所谓反转。
   IoC还有一个另外的名字:“依赖注入 (DI=Dependency Injection)”  ,即由容器动态的将某种依赖关系注入到组件之中 
案例:

 1、原始上传功能:接口
 

package com.xly.ioc.biz;
 
public interface UserBiz {
	
public void upload();
	
 
}

2、接口

package com.xly.ioc.biz.impl;
 
import com.xly.ioc.biz.UserBiz;
 
/**
 * 功能:上传功能
 * 如更改功能:1.限定上传文件大小
 *         2.限定上传文件类别 (就要更改原本代码)
 * 总结:1。更新版本需要改动原有代码
 * 2.相关调用此方法的模块伴随着巨大的风险
 * @author zjjt
 *
 */
public class UserBizImpl implements UserBiz{
	
@Override
public void upload() {
System.out.println("循规蹈矩的开发出来");
	
}
 
}

3、UserAction

package com.xly.ioc.web;
 
import com.xly.ioc.biz.UserBiz;
import com.xly.ioc.biz.impl.UserBizImpl;
 
public class UserAction {
	private UserBiz userBiz=new UserBizImpl();
	
	public void upload() {
		 userBiz.upload();
	}
	public static void main(String[] args) {
		UserAction userAction =new UserAction();
		userAction.upload();
	}
 
}

结果

三:spring的使用 

1、导入jar包

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.xly</groupId>
  <artifactId>maven_4</artifactId>
  <packaging>war</packaging>
  <version>0.0.1-SNAPSHOT</version>
  <name>maven_4 Maven Webapp</name>
  <url>http://maven.apache.org</url>
  <properties>
		<spring.version>5.0.1.RELEASE</spring.version>
		<javax.servlet.version>4.0.0</javax.servlet.version>
		<junit.version>4.12</junit.version>
	</properties>
  <dependencies>
    <dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>3.8.1</version>
			<scope>test</scope>
		</dependency>
		<!-- 2、导入spring依赖 -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-context</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-aspects</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<!-- 5.1、junit -->
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>${junit.version}</version>
			<scope>test</scope>
		</dependency>
		<!-- 5.2、servlet -->
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>javax.servlet-api</artifactId>
			<version>${javax.servlet.version}</version>
			<scope>provided</scope>
		</dependency>
  </dependencies>
  <build>
    <finalName>maven_4</finalName>
    <plugins>
    <plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>3.7.0</version>
				<configuration>
					<source>1.8</source>
					<target>1.8</target>
					<encoding>UTF-8</encoding>
				</configuration>
			</plugin>
    </plugins>
  </build>
</project>

2、核心配置文件(spring-context.xml)

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">
 
 
</beans>

3、进行xml配置

package com.xly.ioc.web;
 
import com.xly.ioc.biz.UserBiz;
import com.xly.ioc.biz.impl.UserBizImpl2;
 
 
public class PersonAction {
private UserBiz userBiz;
 
	public UserBiz getUserBiz() {
	return userBiz;
}
 
public void setUserBiz(UserBiz userBiz) {
	this.userBiz = userBiz;
}
 
	public void upload() {
		 userBiz.upload();
	}
 
}

4、由配置文件负责配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">
 
<!--本文件中配置整个项目中包含的所有javabean  目的在于spring统一管理-->
<bean name="userBiz" class="com.zy.ioc.biz.impl.UserBizImpl"></bean>
<bean name="userBiz2" class="com.zy.ioc.biz.impl.UserBizImpl2"></bean>
<bean name="personAction" class="com.zy.ioc.web.PersonAction">
<property name="userBiz" ref="userBiz1"></property>
</bean>
<bean name="userAction" class="com.xly.ioc.web.UserAction"></bean>
 
</beans>

运行结果

这样我们就可以不用更改源代码了

 

三:spring三种传参

一、set传参

package com.xly.ioc.web;
 
import java.util.List;
 
public class ParamAction {
 
	private int age;
	private String name;
	private List<String> hobby;
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public List<String> getHobby() {
		return hobby;
	}
	public void setHobby(List<String> hobby) {
		this.hobby = hobby;
	}
	
	
	public void execute() {
		System.out.println(this.age);
		System.out.println(this.name);
		System.out.println(this.hobby);
	}
	
}

2、配置

<property name="name" value="影子1"></property>
<property name="age" value="18"></property>
<property name="hobby" >
<list>
<value>打羽毛球</value>
<value>追剧</value>
</list>
</property>

3、测试

package com.xly.ioc.test;
 
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
import com.xly.ioc.web.ParamAction;
import com.xly.ioc.web.PersonAction;
 
public class IocTest {
	public static void main(String[] args) {
	//建模
	
		ApplicationContext applicationContext=new  ClassPathXmlApplicationContext("/spring-context.xml");
	
		ParamAction paramAction= (ParamAction)applicationContext.getBean("paramAction");
		paramAction.execute();
	
	
	}
 
}

运行结果

 二、构造传参

package com.xly.ioc.web;
 
import java.util.List;
 
public class ParamAction {
 
	private int age;
	private String name;
	private List<String> hobby;
public ParamAction(int age, String name, List<String> hobby) {
		super();
		this.age = age;
		this.name = name;
		this.hobby = hobby;
	}
	public ParamAction() {
		// TODO Auto-generated constructor stub
	}
	
	public void execute() {
		System.out.println(this.age);
		System.out.println(this.name);
		System.out.println(this.hobby);
	}
	
}

2、配置

<constructor-arg name="name" value="影子2"></constructor-arg>
<constructor-arg  name="age" value="18"></constructor-arg>
<constructor-arg name="hobby" >
<list>
<value>打羽毛球</value>
<value>追剧</value>
</list>
</constructor-arg>

运行结果


四:spring与tomcat的整合

假如spring-context.xml中配置了几百个类,测试建模的时间过程非常久;

javabean每建一次模,时间就越久,性能就越差,所以将建模放到监听器中

1.监听类 

package com.xly.ioc.listenner;
 
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.http.HttpSessionListener;
 
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
import com.xly.ioc.web.ParamAction;
 
public class SpringLoaderListener implements ServletContextListener{
@Override
public void contextInitialized(ServletContextEvent sce) {
 
    
    System.out.println("监听器方法执行.....");
    ApplicationContext applicationContext=new  ClassPathXmlApplicationContext("/spring-context.xml");
    sce.getServletContext().setAttribute("SpringContext", applicationContext);
    
}
}


2.xml配置

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">
  <display-name>Archetype Created Web Application</display-name>
<listener>
 
<listener-class>com.xly.ioc.listenner.SpringLoaderListener</listener-class>
</listener>
</web-app>


3.测试

package com.xly.ioc.web;
 
import java.io.IOException;
 
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
@WebServlet("/user")
public class UserServlet extends HttpServlet{
 
    @Override
    public void service(ServletRequest req, ServletResponse res) throws ServletException, IOException {
ApplicationContext springContext= (ApplicationContext) req.getServletContext().getAttribute("SpringContext");
ParamAction paramAction = (ParamAction) springContext.getBean("paramAction");
paramAction.execute();
    }
 
}

运行结果

注意:spring监听器只会执行一次

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