• spring01

    目录

    一、对spring的理解

    二、spring中ioc的特点

    2.1控制反转

     2.2注入依赖

    方式① set注入

     方式② 构造注入

    方式③ 自动装配

    三、spring与web容器的整合

    一、对spring的理解

    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。

    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。

    二、spring中ioc的特点

    建一个maven项目

    pom.xml

    1. <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    2.   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    3.   <modelVersion>4.0.0modelVersion>
    4.   <groupId>com.cdlgroupId>
    5.   <artifactId>T280_springartifactId>
    6.   <packaging>warpackaging>
    7.   <version>0.0.1-SNAPSHOTversion>
    8.   <name>T280_spring Maven Webappname>
    9.   <url>http://maven.apache.orgurl>
    10.   
    11.   
    12.   <properties>
    13. 		<spring.version>5.0.1.RELEASEspring.version>
    14. 		<javax.servlet.version>4.0.0javax.servlet.version>
    15. 		<junit.version>4.12junit.version>
    16.   properties>
    17.   
    18.   <dependencies>
    19.    <dependency>
    20. 			<groupId>junitgroupId>
    21. 			<artifactId>junitartifactId>
    22. 			<version>3.8.1version>
    23. 			<scope>testscope>
    24. 		dependency>
    25. 		
    26. 		<dependency>
    27. 			<groupId>org.springframeworkgroupId>
    28. 			<artifactId>spring-contextartifactId>
    29. 			<version>${spring.version}version>
    30. 		dependency>
    31. 		<dependency>
    32. 			<groupId>org.springframeworkgroupId>
    33. 			<artifactId>spring-aspectsartifactId>
    34. 			<version>${spring.version}version>
    35. 		dependency>
    36. 		
    37. 		<dependency>
    38. 			<groupId>junitgroupId>
    39. 			<artifactId>junitartifactId>
    40. 			<version>${junit.version}version>
    41. 			<scope>testscope>
    42. 		dependency>
    43. 		
    44. 		<dependency>
    45. 			<groupId>javax.servletgroupId>
    46. 			<artifactId>javax.servlet-apiartifactId>
    47. 			<version>${javax.servlet.version}version>
    48. 			<scope>providedscope>
    49. 		dependency>
    50.   dependencies>
    51.   <build>
    52.     <finalName>T280_springfinalName>
    53.     <plugins>
    54. 			<plugin>
    55. 				<groupId>org.apache.maven.pluginsgroupId>
    56. 				<artifactId>maven-compiler-pluginartifactId>
    57. 				<version>3.7.0version>
    58. 				<configuration>
    59. 					<source>1.8source>
    60. 					<target>1.8target>
    61. 					<encoding>UTF-8encoding>
    62. 				configuration>
    63. 			plugin>
    64. 		plugins>
    65.   build>
    66. project>

    web.xml

    1. <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    2.          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    3.          xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
    4.          version="3.1">
    5.   <display-name>Archetype Created Web Applicationdisplay-name>
    6. web-app>
    7.

    2.1控制反转

    建一个com.cdl.biz的包

    UserBiz

    1. package com.cdl.biz;
    2.  
    3. /**
    4.  * 用户业务类
    5.  * @author Lenovo
    6.  *
    7.  */
    8. public interface UserBiz {
    9. 	void list();
    10. }

    建一个com.cdl.biz.impl的包

    UserBizImpl1

    1. package com.cdl.biz.impl;
    2.  
    3. import com.cdl.biz.UserBiz;
    4.  
    5. public class UserBizImpl1 implements UserBiz{
    6.  
    7. 	@Override
    8. 	public void list() {
    9. 		System.out.println("查询用户数据。。按照年龄排序。");
    10. 	}
    11. 	
    12. }

    UserBizImpl2

    1. package com.cdl.biz.impl;
    2.  
    3. import com.cdl.biz.UserBiz;
    4.  
    5. public class UserBizImpl2 implements UserBiz{
    6.  
    7. 	@Override
    8. 	public void list() {
    9. 		System.out.println("查询用户数据。。按照入职时间排序。");
    10. 	}
    11. 	
    12. }

    建一个com.cdl.web的包

    OrderAction

    1. package com.cdl.web;
    2.  
    3. import com.cdl.biz.UserBiz;
    4. import com.cdl.biz.impl.UserBizImpl1;
    5.  
    6. public class OrderAction {
    7.  
    8. private UserBiz userBiz = new UserBizImpl1();
    9. 	
    10. 	public void list() {
    11. 		userBiz.list();
    12. 	}
    13. 	
    14. }

    UserAction

    1. package com.cdl.web;
    2.  
    3. import com.cdl.biz.UserBiz;
    4. import com.cdl.biz.impl.UserBizImpl1;
    5.  
    6. public class UserAction {
    7. 	
    8. 	private UserBiz userBiz = new UserBizImpl1();
    9. 	
    10. 	public void list() {
    11. 		userBiz.list();
    12. 	}
    13. }

    常规做法即运用spring之前的处理方法

    * 需求：
     * 同时在用户模块，订单模块拿到所有的用户数据
     * 
     * 需求变更1：
     * 同时在用户模块，订单模块拿到所有的用户数据，并且要求用户数据是通过年龄排序的
     * 对应策略：修改UserBiz中list方法，添加排序功能
     * 
     * 需求变更2：
     * 同时在用户模块，订单模块拿到所有的用户数据，并且要求用户数据是通过注册时间排序的
     * 对应策略，修改UserBiz中list方法，添加排序功能，按照时间点排序

     总结：
     * 最原始：频繁修改业务层biz的代码
     * 多实现：凡是涉及到用户业务层调用的地方，都需要修改代码

    运用spring处理

     将spring的配置文件加入

    spring-context.xml

    2. <beans xmlns="http://www.springframework.org/schema/beans"
    3. 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    4. 	xmlns:aop="http://www.springframework.org/schema/aop"
    5. 	xmlns:context="http://www.springframework.org/schema/context"
    6. 	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    7. 		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
    8. 		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">
    9.  
    10.  
    11. beans>

    注意：一定要在有网络的情况下进行，否则约束不生效

    IOC的主要作用管理整个项目的Javabean：依靠依赖注入、控制反转的特点进行管理

     spring-context.xml

    1.  
    3. <beans xmlns="http://www.springframework.org/schema/beans"
    4. 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    5. 	xmlns:aop="http://www.springframework.org/schema/aop"
    6. 	xmlns:context="http://www.springframework.org/schema/context"
    7. 	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    8. 		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
    9. 		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">
    10.  
    11. 	
    12. 	
    13. 	<bean class="com.cdl.biz.impl.UserBizImpl2" id="userBiz2">bean>
    14. 	<bean class="com.cdl.web.UserAction" id="userAction">
    15. 		<property name="userBiz" ref="userBiz2">property>
    16. 	bean>
    17. 	<bean class="com.cdl.web.OrderAction" id="orderAction">bean>
    18. beans>

    UserAction

    1. package com.cdl.web;
    2.  
    3. import com.cdl.biz.UserBiz;
    4. import com.cdl.biz.impl.UserBizImpl1;
    5.  
    6. public class UserAction {
    7. 	
    8. 	//private UserBiz userBiz = new UserBizImpl1();
    9. 	private UserBiz userBiz;
    10. 	
    11. 	public void list() {
    12. 		userBiz.list();
    13. 	}
    14. 	public UserBiz getUserBiz() {
    15. 		return userBiz;
    16. 	}
    17. 	public void setUserBiz(UserBiz userBiz) {
    18. 		this.userBiz = userBiz;
    19. 	}
    20. 	
    21. 	
    22. }

    建一个com.cdl.ioc的包

    在里面建一个Demo1的类

    建模，打印com.cdl.biz.impl.UserBizImpl2中的语句

    1. package com.cdl.ioc;
    2.  
    3. import org.springframework.context.support.ClassPathXmlApplicationContext;
    4.  
    5. import com.cdl.web.UserAction;
    6.  
    7. public class Demo1 {
    8. 	@SuppressWarnings("resource")
    9. 	public static void main(String[] args) {
    10. 		//建模
    11. 		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("/spring-context.xml");
    12. 		UserAction userAction = (UserAction) context.getBean("userAction");
    13. 		userAction.list();
    14. 	}
    15. 	
    16. 	
    17. }

     运行结果：

     可见 能拿到

    总结

    1.对spring框架的配置文件进行建模，建模之后spring-context.xml中所有的Javabean信息
     都会加载进spring容器的上下文中
     2.上下文中就包含了spring-context.xml 所有对象

     测试orderaction也拿到相同结果，配置和orderaction都如useraction一致修改

    1. package com.cdl.web;
    2.  
    3. import com.cdl.biz.UserBiz;
    4. import com.cdl.biz.impl.UserBizImpl1;
    5.  
    6. public class OrderAction {
    7.  
    8. //private UserBiz userBiz = new UserBizImpl1();
    9. 	
    10. 	private UserBiz userBiz;
    11. 	
    12. 	public void list() {
    13. 		userBiz.list();
    14. 	}
    15.  
    16. 	public UserBiz getUserBiz() {
    17. 		return userBiz;
    18. 	}
    19.  
    20. 	public void setUserBiz(UserBiz userBiz) {
    21. 		this.userBiz = userBiz;
    22. 	}
    23. 	
    24. 	
    25. 	
    26. }

    2. <beans xmlns="http://www.springframework.org/schema/beans"
    3. 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    4. 	xmlns:aop="http://www.springframework.org/schema/aop"
    5. 	xmlns:context="http://www.springframework.org/schema/context"
    6. 	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    7. 		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
    8. 		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">
    9.  
    10. 	
    11. 	
    12. 	<bean class="com.cdl.biz.impl.UserBizImpl2" id="userBiz2">bean>
    13. 	<bean class="com.cdl.web.UserAction" id="userAction">
    14. 		<property name="userBiz" ref="userBiz2">property>
    15. 	bean>
    16. 	<bean class="com.cdl.web.OrderAction" id="orderAction">
    17. 		<property name="userBiz" ref="userBiz2">property>
    18. 	bean>
    19. beans>
    1. package com.cdl.ioc;
    2.  
    3. import org.springframework.context.support.ClassPathXmlApplicationContext;
    4.  
    5. import com.cdl.web.OrderAction;
    6. import com.cdl.web.UserAction;
    7. /**
    8.  * 1.对spring框架的配置文件进行建模，建模之后spring-context.xml中所有的Javabean信息
    9.  * 都会加载进spring容器的上下文中
    10.  * 2.上下文中就包含了spring-context.xml 所有对象
    11.  * @author Lenovo
    12.  *
    13.  */
    14. public class Demo1 {
    15. 	@SuppressWarnings("resource")
    16. 	public static void main(String[] args) {
    17. 		//建模
    18. 		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("/spring-context.xml");
    19. 		UserAction userAction = (UserAction) context.getBean("userAction");
    20. 		userAction.list();
    21. 		
    22. 		OrderAction orderAction = (OrderAction) context.getBean("orderAction");
    23. 		orderAction.list();
    24. 	}
    25. 	
    26. 	
    27. }

    结果：

     若是要按年龄排序，就只需要修改配置文件就OK了

    2. <beans xmlns="http://www.springframework.org/schema/beans"
    3. 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    4. 	xmlns:aop="http://www.springframework.org/schema/aop"
    5. 	xmlns:context="http://www.springframework.org/schema/context"
    6. 	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    7. 		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
    8. 		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">
    9.  
    10. 	
    11. 	<bean class="com.cdl.biz.impl.UserBizImpl1" id="userBiz2">bean>
    12. 	<bean class="com.cdl.web.UserAction" id="userAction">
    13. 		<property name="userBiz" ref="userBiz2">property>
    14. 	bean>
    15. 	<bean class="com.cdl.web.OrderAction" id="orderAction">
    16. 		<property name="userBiz" ref="userBiz2">property>
    17. 	bean>
    18. beans>

     结论：IOC特点（控制反转）：将创建对象的权利反转给spring容器来完成

     2.2注入依赖

    方式① set注入

     

     可见报错的原因就是找不到set的方法

    接下来用一个例子（多注入三个属性）来更深入的了解

    UserAction

    1. package com.cdl.web;
    2.  
    3. import java.util.List;
    4.  
    5. import com.cdl.biz.UserBiz;
    6. import com.cdl.biz.impl.UserBizImpl1;
    7.  
    8. public class UserAction {
    9. 	
    10. 	//private UserBiz userBiz = new UserBizImpl1();
    11. 	private UserBiz userBiz;
    12. 	
    13. 	
    14. 	public UserBiz getUserBiz() {
    15. 		return userBiz;
    16. 	}
    17. 	public void setUserBiz(UserBiz userBiz) {
    18. 		this.userBiz = userBiz;
    19. 	}
    20. 	
    21. 	private String name;
    22. 	private int age;
    23. 	private List hobby;
    24.  
    25. 	public String getName() {
    26. 		return name;
    27. 	}
    28.  
    29. 	public void setName(String name) {
    30. 		this.name = name;
    31. 	}
    32.  
    33. 	public int getAge() {
    34. 		return age;
    35. 	}
    36.  
    37. 	public void setAge(int age) {
    38. 		this.age = age;
    39. 	}
    40.  
    41. 	public List getHobby() {
    42. 		return hobby;
    43. 	}
    44.  
    45. 	public void setHobby(List hobby) {
    46. 		this.hobby = hobby;
    47. 	}
    48. 	
    49. 	public void list() {
    50. 		System.out.println(name);
    51. 		System.out.println(age);
    52. 		System.out.println(hobby);
    53. 		userBiz.list();
    54. 	}
    55. 	
    56. }
    2. <beans xmlns="http://www.springframework.org/schema/beans"
    3. 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    4. 	xmlns:aop="http://www.springframework.org/schema/aop"
    5. 	xmlns:context="http://www.springframework.org/schema/context"
    6. 	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    7. 		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
    8. 		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">
    9.  
    10. 	
    11. 	<bean class="com.cdl.biz.impl.UserBizImpl1" id="userBiz2">bean>
    12. 	<bean class="com.cdl.web.UserAction" id="userAction">
    13. 		<property name="userBiz" ref="userBiz2">property>
    14. 		
    15. 		<property name="age" value="22">property>
    16. 		<property name="name" value="cdl">property>
    17. 		<property name="hobby">
    18. 			<list>
    19. 				<value>篮球value>
    20. 				<value>足球value>
    21. 				<value>唱歌value>
    22. 			list>
    23. 		property>
    24. 	bean>
    25. 	<bean class="com.cdl.web.OrderAction" id="orderAction">
    26. 		<property name="userBiz" ref="userBiz2">property>
    27. 	bean>
    28. beans>
    1. package com.cdl.ioc;
    2.  
    3. import org.springframework.context.support.ClassPathXmlApplicationContext;
    4.  
    5. import com.cdl.web.OrderAction;
    6. import com.cdl.web.UserAction;
    7. /**
    8.  * 1.对spring框架的配置文件进行建模，建模之后spring-context.xml中所有的Javabean信息
    9.  * 都会加载进spring容器的上下文中
    10.  * 2.上下文中就包含了spring-context.xml 所有对象
    11.  * @author Lenovo
    12.  * 
    13.  * IOC特点（控制反转）：将创建对象的权利反转给spring容器来完成
    14.  * 
    15.  *
    16.  */
    17. public class Demo1 {
    18. 	@SuppressWarnings("resource")
    19. 	public static void main(String[] args) {
    20. 		//建模
    21. 		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("/spring-context.xml");
    22. 		UserAction userAction = (UserAction) context.getBean("userAction");
    23. 		userAction.list();
    24. 		
    25. 		OrderAction orderAction = (OrderAction) context.getBean("orderAction");
    26. 		orderAction.list();
    27. 	}
    28. 	
    29. 	
    30. }

    结果：

     方式② 构造注入

    OrderAction

    1. package com.cdl.web;
    2.  
    3. import java.util.List;
    4.  
    5. import com.cdl.biz.UserBiz;
    6. import com.cdl.biz.impl.UserBizImpl1;
    7.  
    8. /**
    9.  * 依赖注入的三种方式：
    10.  * 1.set注入
    11.  * 2.构造注入
    12.  * 3.自动装配
    13.  *  byName
    14.  *  byType
    15.  * @author Lenovo
    16.  *
    17.  */
    18. public class OrderAction {
    19.  
    20. //private UserBiz userBiz = new UserBizImpl1();
    21. 	
    22. 	private UserBiz userBiz;
    23. 	
    24.  
    25. 	public UserBiz getUserBiz() {
    26. 		return userBiz;
    27. 	}
    28.  
    29. 	public void setUserBiz(UserBiz userBiz) {
    30. 		this.userBiz = userBiz;
    31. 	}
    32. 	
    33. 	private String name;
    34. 	private int age;
    35. 	private List hobby;
    36.  
    37. 	public OrderAction(String name, int age, List hobby) {
    38. 		super();
    39. 		this.name = name;
    40. 		this.age = age;
    41. 		this.hobby = hobby;
    42. 	}
    43.  
    44. 	public OrderAction() {
    45. 		super();
    46. 		// TODO Auto-generated constructor stub
    47. 	}
    48. 	
    49. 	public void list() {
    50. 		System.out.println(name);
    51. 		System.out.println(age);
    52. 		System.out.println(hobby);
    53. 		userBiz.list();
    54. 	}
    55. 	
    56. }
    2. <beans xmlns="http://www.springframework.org/schema/beans"
    3. 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    4. 	xmlns:aop="http://www.springframework.org/schema/aop"
    5. 	xmlns:context="http://www.springframework.org/schema/context"
    6. 	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    7. 		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
    8. 		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">
    9.  
    10. 	
    11. 	<bean class="com.cdl.biz.impl.UserBizImpl1" id="userBiz2">bean>
    12. 	
    13. 	
    14. 	<bean class="com.cdl.web.UserAction" id="userAction">
    15. 		<property name="userBiz" ref="userBiz2">property>
    16. 		<property name="age" value="22">property>
    17. 		<property name="name" value="cdl">property>
    18. 		<property name="hobby">
    19. 			<list>
    20. 				<value>篮球value>
    21. 				<value>足球value>
    22. 				<value>唱歌value>
    23. 			list>
    24. 		property>
    25. 	bean>
    26. 	
    27. 	
    28. 	<bean class="com.cdl.web.OrderAction" id="orderAction">
    29. 		<property name="userBiz" ref="userBiz2">property>
    30. 		<constructor-arg name="name" value="cdl">constructor-arg>
    31. 		<constructor-arg name="age" value="23">constructor-arg>
    32. 		<constructor-arg name="hobby">
    33. 				<list>
    34. 				<value>篮球1value>
    35. 				<value>足球1value>
    36. 				<value>唱歌1value>
    37. 				list>
    38. 		constructor-arg>
    39. 	bean>
    40. beans>

    在Demo1运行

    方式③ 自动装配

    将set和构造的注入 注释

    byType不报错 byName报错

     

     

     

    byType报错 byName不报错

     

     

    自动装配
     default-autowire="byName" 
    byName:是通过spring管理的bean对象的ID进行查找，如果找不到，则注入失败，反之成功
     byType：是通过spring管理的bean对象的接口实现类进行查找，如果没有或者2个以上，则注入失败，反之成功

    三、spring与web容器的整合

    分析：

    spring与web容器的整合原理
        why:建模的过程是十分耗时的
      解决问题：
     1.建模必不可少
     2.建模只保障只执行一次
     3.建模后期望在每一个servlet都能够拿到spring的上下文对象ClassPathXmlApplicationContext
      how:
      1.监听器的初始化方法 只执行一次
      2.spring的上下文要存放在Tomcat上下文中

    建一个包com.cdl.ioc.listener

    1. package com.cdl.ioc.listener;
    2.  
    3. import javax.servlet.ServletContext;
    4. import javax.servlet.ServletContextEvent;
    5. import javax.servlet.ServletContextListener;
    6.  
    7. import org.springframework.context.support.ClassPathXmlApplicationContext;
    8.  
    9. public class SpringLoadListener implements ServletContextListener{
    10. 	
    11. 	@Override
    12. 	public void contextInitialized(ServletContextEvent sce) {
    13. 		System.out.println("初始化执行");
    14. 		ServletContext servletContext = sce.getServletContext();
    15. 		String springConfigLocation = servletContext.getInitParameter("springConfigLocation");
    16. 		System.out.println(springConfigLocation+"...");
    17. 		//拿到spring上下文
    18. 		ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("/spring-context.xml");
    19. 		//将spring的上下文保存在Tomcat上下文中
    20. 		servletContext.setAttribute("springContext", context);
    21. 	}
    22. 	
    23. }

    在com.cdl.ioc中建一个类DemoServlet

    1. package com.cdl.ioc;
    2.  
    3. import java.io.IOException;
    4.  
    5. import javax.servlet.ServletException;
    6. import javax.servlet.annotation.WebServlet;
    7. import javax.servlet.http.HttpServlet;
    8. import javax.servlet.http.HttpServletRequest;
    9. import javax.servlet.http.HttpServletResponse;
    10.  
    11. import org.springframework.context.support.ClassPathXmlApplicationContext;
    12.  
    13. import com.cdl.web.UserAction;
    14.  
    15. /**
    16.  * spring与web容器的整合原理
    17.  * 	why:建模的过程是十分耗时的
    18.  * 解决问题：
    19.  * 1.建模必不可少
    20.  * 2.建模只保障只执行一次
    21.  * 3.建模后期望在每一个servlet都能够拿到spring的上下文对象ClassPathXmlApplicationContext
    22.  * how:
    23.  * 1.监听器的初始化方法 只执行一次
    24.  * 2.spring的上下文要存放在Tomcat上下文中
    25.  * @author Lenovo
    26.  *
    27.  */
    28. @WebServlet("/springDemo")
    29. public class DemoServlet extends HttpServlet{
    30. 	
    31. 	@Override
    32. 	protected void service(HttpServletRequest arg0, HttpServletResponse arg1){
    33. 		//ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("/spring-context.xml");
    34. 		ClassPathXmlApplicationContext context = (ClassPathXmlApplicationContext) arg0.getServletContext().getAttribute("springContext");
    35. 		UserAction userAction = (UserAction) context.getBean("userAction");
    36. 		userAction.list();
    37. 	}
    38. 	
    39. }

    spring-context.xml

    2. <beans xmlns="http://www.springframework.org/schema/beans"
    3. 	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    4. 	xmlns:aop="http://www.springframework.org/schema/aop"
    5. 	xmlns:context="http://www.springframework.org/schema/context"
    6. 	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    7. 		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
    8. 		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd">
    9.  
    10. 	
    11. 	<bean class="com.cdl.biz.impl.UserBizImpl1" id="userBiz">bean>
    12. 	<bean class="com.cdl.biz.impl.UserBizImpl1" id="userBiz1">bean>
    13. 	
    14. 	<bean class="com.cdl.web.UserAction" id="userAction">
    15. 		<property name="userBiz" ref="userBiz1">property> 
    16. 		<property name="age" value="22">property>
    17. 		<property name="name" value="cdl">property>
    18. 		<property name="hobby">
    19. 			<list>
    20. 				<value>篮球value>
    21. 				<value>足球value>
    22. 				<value>唱歌value>
    23. 			list>
    24. 		property>
    25. 	bean>
    26. 	
    27. 	
    28. 	<bean class="com.cdl.web.OrderAction" id="orderAction">
    29. 		<property name="userBiz" ref="userBiz1">property> 
    30. 		<constructor-arg name="name" value="cdl">constructor-arg>
    31. 		<constructor-arg name="age" value="23">constructor-arg>
    32. 		<constructor-arg name="hobby">
    33. 				<list>
    34. 				<value>篮球1value>
    35. 				<value>足球1value>
    36. 				<value>唱歌1value>
    37. 				list>
    38. 		constructor-arg>
    39. 	bean>
    40. 	
    41. 	
    42. 	
    43. 	
    44. beans>

    web.xml

    1. <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    2.          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    3.          xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
    4.          version="3.1">
    5.   <display-name>Archetype Created Web Applicationdisplay-name>
    6.  
    7. 	<context-param>
    8. 		<param-name>springConfigLocationparam-name>
    9. 		<param-value>/applicationContext.xmlparam-value>
    10. 	context-param>
    11.  
    12. 	<listener>
    13. 		<listener-class>com.cdl.ioc.listener.SpringLoadListenerlistener-class>
    14. 	listener>
    15. web-app>
    16.

    结果：

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  • 原文地址：https://blog.csdn.net/weixin_62735525/article/details/126164581