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spring注解实例一

SpringServletlog4jWebXML 
阅读更多

先来构建一个极为简单的web应用，从controller到dao。不考虑具体实现，只是先对整体架构有一个清晰的了解。

 

我们将用到如下jar包：

引用

aopalliance-1.0.jar
commons-logging-1.1.1.jar
log4j-1.2.15.jar
spring-beans-2.5.6.jar
spring-context-2.5.6.jar
spring-context-support-2.5.6.jar
spring-core-2.5.6.jar
spring-tx-2.5.6.jar
spring-web-2.5.6.jar
spring-webmvc-2.5.6.jar


先看web.xml

Xml代码 复制代码
  1. <?xml version="1.0" encoding="UTF-8"?>  
  2. <web-app  
  3.     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
  4.     xmlns="http://java.sun.com/xml/ns/javaee"  
  5.     xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"  
  6.     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"  
  7.     id="WebApp_ID"  
  8.     version="2.5">  
  9.     <display-name>spring</display-name>  
  10.     <!-- 应用路径 -->  
  11.     <context-param>  
  12.         <param-name>webAppRootKey</param-name>  
  13.         <param-value>spring.webapp.root</param-value>  
  14.     </context-param>  
  15.     <!-- Log4J 配置  -->  
  16.     <context-param>  
  17.         <param-name>log4jConfigLocation</param-name>  
  18.         <param-value>classpath:log4j.xml</param-value>  
  19.     </context-param>  
  20.     <context-param>  
  21.         <param-name>log4fRefreshInterval</param-name>  
  22.         <param-value>60000</param-value>  
  23.     </context-param>  
  24.     <!--Spring上下文 配置  -->  
  25.     <context-param>  
  26.         <param-name>contextConfigLocation</param-name>  
  27.         <param-value>/WEB-INF/applicationContext.xml</param-value>  
  28.     </context-param>  
  29.     <!-- 字符集 过滤器  -->  
  30.     <filter>  
  31.         <filter-name>CharacterEncodingFilter</filter-name>  
  32.         <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>  
  33.         <init-param>  
  34.             <param-name>encoding</param-name>  
  35.             <param-value>UTF-8</param-value>  
  36.         </init-param>  
  37.         <init-param>  
  38.             <param-name>forceEncoding</param-name>  
  39.             <param-value>true</param-value>  
  40.         </init-param>  
  41.     </filter>  
  42.     <filter-mapping>  
  43.         <filter-name>CharacterEncodingFilter</filter-name>  
  44.         <url-pattern>/*</url-pattern>  
  45.     </filter-mapping>  
  46.     <!-- Spring 监听器 -->  
  47.     <listener>  
  48.         <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>  
  49.     </listener>  
  50.     <listener>  
  51.         <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>  
  52.     </listener>  
  53.     <!-- Spring 分发器 -->  
  54.     <servlet>  
  55.         <servlet-name>spring</servlet-name>  
  56.         <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>  
  57.         <init-param>  
  58.             <param-name>contextConfigLocation</param-name>  
  59.             <param-value>/WEB-INF/servlet.xml</param-value>  
  60.         </init-param>  
  61.     </servlet>  
  62.     <servlet-mapping>  
  63.         <servlet-name>spring</servlet-name>  
  64.         <url-pattern>*.do</url-pattern>  
  65.     </servlet-mapping>  
  66.     <welcome-file-list>  
  67.         <welcome-file>index.html</welcome-file>  
  68.         <welcome-file>index.htm</welcome-file>  
  69.         <welcome-file>index.jsp</welcome-file>  
  70.         <welcome-file>default.html</welcome-file>  
  71.         <welcome-file>default.htm</welcome-file>  
  72.         <welcome-file>default.jsp</welcome-file>  
  73.     </welcome-file-list>  
  74. </web-app>   
<?xml version="1.0" encoding="UTF-8"?>
<web-app
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://java.sun.com/xml/ns/javaee"
	xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	id="WebApp_ID"
	version="2.5">
	<display-name>spring</display-name>
	<!-- 应用路径 -->
	<context-param>
		<param-name>webAppRootKey</param-name>
		<param-value>spring.webapp.root</param-value>
	</context-param>
	<!-- Log4J 配置  -->
	<context-param>
		<param-name>log4jConfigLocation</param-name>
		<param-value>classpath:log4j.xml</param-value>
	</context-param>
	<context-param>
		<param-name>log4fRefreshInterval</param-name>
		<param-value>60000</param-value>
	</context-param>
	<!--Spring上下文 配置  -->
	<context-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>/WEB-INF/applicationContext.xml</param-value>
	</context-param>
	<!-- 字符集 过滤器  -->
	<filter>
		<filter-name>CharacterEncodingFilter</filter-name>
		<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
		<init-param>
			<param-name>encoding</param-name>
			<param-value>UTF-8</param-value>
		</init-param>
		<init-param>
			<param-name>forceEncoding</param-name>
			<param-value>true</param-value>
		</init-param>
	</filter>
	<filter-mapping>
		<filter-name>CharacterEncodingFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
	<!-- Spring 监听器 -->
	<listener>
		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>
	<listener>
		<listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
	</listener>
	<!-- Spring 分发器 -->
	<servlet>
		<servlet-name>spring</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>/WEB-INF/servlet.xml</param-value>
		</init-param>
	</servlet>
	<servlet-mapping>
		<servlet-name>spring</servlet-name>
		<url-pattern>*.do</url-pattern>
	</servlet-mapping>
	<welcome-file-list>
		<welcome-file>index.html</welcome-file>
		<welcome-file>index.htm</welcome-file>
		<welcome-file>index.jsp</welcome-file>
		<welcome-file>default.html</welcome-file>
		<welcome-file>default.htm</welcome-file>
		<welcome-file>default.jsp</welcome-file>
	</welcome-file-list>
</web-app>


有不少人问我，这段代码是什么：

Xml代码 复制代码
  1. <!-- 应用路径 -->  
  2. <context-param>  
  3.     <param-name>webAppRootKey</param-name>  
  4.     <param-value>spring.webapp.root</param-value>  
  5. </context-param>   
	<!-- 应用路径 -->
	<context-param>
		<param-name>webAppRootKey</param-name>
		<param-value>spring.webapp.root</param-value>
	</context-param>


这是当前应用的路径变量，也就是说你可以在其他代码中使用${spring.webapp.root}指代当前应用路径。我经常用它来设置log的输出目录。
为什么要设置参数log4jConfigLocation？

Xml代码 复制代码
  1. <!-- Log4J 配置  -->  
  2.     <context-param>  
  3.         <param-name>log4jConfigLocation</param-name>  
  4.         <param-value>classpath:log4j.xml</param-value>  
  5.     </context-param>  
  6.     <context-param>  
  7.         <param-name>log4fRefreshInterval</param-name>  
  8.         <param-value>60000</param-value>  
  9.     </context-param>   
<!-- Log4J 配置  -->
	<context-param>
		<param-name>log4jConfigLocation</param-name>
		<param-value>classpath:log4j.xml</param-value>
	</context-param>
	<context-param>
		<param-name>log4fRefreshInterval</param-name>
		<param-value>60000</param-value>
	</context-param>


这是一种基本配置，spring中很多代码使用了不同的日志接口，既有log4j也有commons-logging，这里只是强制转换为log4j！并且，log4j的配置文件只能放在classpath根路径。同时，需要通过commons-logging配置将日志控制权转交给log4j。同时commons-logging.properties必须放置在classpath根路径。
commons-logging内容：

Properties代码 复制代码
  1. org.apache.commons.logging.Log=org.apache.commons.logging.impl.Log4JLogger  
org.apache.commons.logging.Log=org.apache.commons.logging.impl.Log4JLogger


最后，记得配置log4j的监听器：

Xml代码 复制代码
  1. <listener>  
  2.     <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>  
  3. </listener>   
	<listener>
		<listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
	</listener>


接下来，我们需要配置两套配置文件，applicationContext.xml和servlet.xml。
applicationContext.xml用于对应用层面做整体控制。按照分层思想，统领service层和dao层。servlet.xml则单纯控制controller层。

Xml代码 复制代码
  1. <?xml version="1.0" encoding="UTF-8"?>  
  2. <beans  
  3.     xmlns="http://www.springframework.org/schema/beans"  
  4.     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
  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/context http://www.springframework.org/schema/context/spring-context.xsd">  
  8.     <import  
  9.         resource="service.xml" />  
  10.     <import  
  11.         resource="dao.xml" />  
  12. </beans>   
<?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: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/context http://www.springframework.org/schema/context/spring-context.xsd">
	<import
		resource="service.xml" />
	<import
		resource="dao.xml" />
</beans>


applicationContext.xml什么都不干，它只管涉及到整体需要的配置，并且集中管理。
这里引入了两个配置文件service.xml和dao.xml分别用于业务、数据处理。
service.xml

Xml代码 复制代码
  1. <?xml version="1.0" encoding="UTF-8"?>  
  2. <beans  
  3.     xmlns="http://www.springframework.org/schema/beans"  
  4.     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
  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/context http://www.springframework.org/schema/context/spring-context.xsd">  
  8.     <context:component-scan  
  9.         base-package="org.zlex.spring.service" />  
  10. </beans>   
<?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: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/context http://www.springframework.org/schema/context/spring-context.xsd">
	<context:component-scan
		base-package="org.zlex.spring.service" />
</beans>


注意，这里通过<context:component-scan />标签指定了业务层的基础包路径——“org.zlex.spring.service”。也就是说，业务层相关实现均在这一层。这是有必要的分层之一。
dao.xml

Xml代码 复制代码
  1. <?xml version="1.0" encoding="UTF-8"?>  
  2. <beans  
  3.     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.     xmlns:tx="http://www.springframework.org/schema/tx"  
  8.     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd   
  9.         http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd   
  10.         http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd   
  11.         http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">  
  12.     <context:component-scan  
  13.         base-package="org.zlex.spring.dao" />  
  14. </beans>   
<?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"
	xmlns:tx="http://www.springframework.org/schema/tx"
	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.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd">
	<context:component-scan
		base-package="org.zlex.spring.dao" />
</beans>


dao层如法炮制，包路径是"org.zlex.spring.dao"。从这个角度看，注解还是很方便的！
最后，我们看看servlet.xml

Xml代码 复制代码
  1. <?xml version="1.0" encoding="UTF-8"?>  
  2. <beans  
  3.     xmlns="http://www.springframework.org/schema/beans"  
  4.     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
  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/context http://www.springframework.org/schema/context/spring-context.xsd">  
  8.     <context:component-scan  
  9.         base-package="org.zlex.spring.controller" />  
  10.     <bean  
  11.         id="urlMapping"  
  12.         class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />  
  13.     <bean  
  14.         class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />  
  15. </beans>   
<?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: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/context http://www.springframework.org/schema/context/spring-context.xsd">
	<context:component-scan
		base-package="org.zlex.spring.controller" />
	<bean
		id="urlMapping"
		class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />
	<bean
		class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
</beans>


包路径配置就不细说了，都是一个概念。最重要的时候后面两个配置，这将使得注解生效！
“org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping”是默认实现，可以不写，Spring容器默认会默认使用该类。
“org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter”直接关系到多动作控制器配置是否可用！
简单看一下代码结构，如图：

Account类是来存储账户信息，属于域对象，极为简单，代码如下所示：
Account.java

Java代码 复制代码
  1. /**  
  2.  * 2010-1-23  
  3.  */  
  4. package org.zlex.spring.domain;   
  5.   
  6. import java.io.Serializable;   
  7.   
  8. /**  
  9.  *   
  10.  * @author <a href="mailto:zlex.dongliang@gmail.com">梁栋</a>  
  11.  * @version 1.0  
  12.  * @since 1.0  
  13.  */  
  14. public class Account implements Serializable {   
  15.   
  16.     /**  
  17.      *   
  18.      */  
  19.     private static final long serialVersionUID = -533698031946372178L;   
  20.   
  21.     private String username;   
  22.     private String password;   
  23.   
  24.     /**  
  25.      * @param username  
  26.      * @param password  
  27.      */  
  28.     public Account(String username, String password) {   
  29.         this.username = username;   
  30.         this.password = password;   
  31.     }   
  32.   
  33.     /**  
  34.      * @return the username  
  35.      */  
  36.     public String getUsername() {   
  37.         return username;   
  38.     }   
  39.   
  40.     /**  
  41.      * @param username the username to set  
  42.      */  
  43.     public void setUsername(String username) {   
  44.         this.username = username;   
  45.     }   
  46.   
  47.     /**  
  48.      * @return the password  
  49.      */  
  50.     public String getPassword() {   
  51.         return password;   
  52.     }   
  53.   
  54.     /**  
  55.      * @param password the password to set  
  56.      */  
  57.     public void setPassword(String password) {   
  58.         this.password = password;   
  59.     }   
  60.        
  61.        
  62. }  
/**
 * 2010-1-23
 */
package org.zlex.spring.domain;

import java.io.Serializable;

/**
 * 
 * @author <a href="mailto:zlex.dongliang@gmail.com">梁栋</a>
 * @version 1.0
 * @since 1.0
 */
public class Account implements Serializable {

	/**
	 * 
	 */
	private static final long serialVersionUID = -533698031946372178L;

	private String username;
	private String password;

	/**
	 * @param username
	 * @param password
	 */
	public Account(String username, String password) {
		this.username = username;
		this.password = password;
	}

	/**
	 * @return the username
	 */
	public String getUsername() {
		return username;
	}

	/**
	 * @param username the username to set
	 */
	public void setUsername(String username) {
		this.username = username;
	}

	/**
	 * @return the password
	 */
	public String getPassword() {
		return password;
	}

	/**
	 * @param password the password to set
	 */
	public void setPassword(String password) {
		this.password = password;
	}
	
	
}


通常，在构建域对象时，需要考虑该对象可能需要进行网络传输，本地缓存，因此建议实现序列化接口Serializable 
我们再来看看控制器，这就稍微复杂了一点代码如下所示：
AccountController .java

Java代码 复制代码
  1. /**  
  2.  * 2010-1-23  
  3.  */  
  4. package org.zlex.spring.controller;   
  5.   
  6. import javax.servlet.http.HttpServletRequest;   
  7. import javax.servlet.http.HttpServletResponse;   
  8.   
  9. import org.springframework.beans.factory.annotation.Autowired;   
  10. import org.springframework.stereotype.Controller;   
  11. import org.springframework.web.bind.ServletRequestUtils;   
  12. import org.springframework.web.bind.annotation.RequestMapping;   
  13. import org.springframework.web.bind.annotation.RequestMethod;   
  14. import org.zlex.spring.service.AccountService;   
  15.   
  16. /**  
  17.  *   
  18.  * @author <a href="mailto:zlex.dongliang@gmail.com">梁栋</a>  
  19.  * @version 1.0  
  20.  * @since 1.0  
  21.  */  
  22. @Controller  
  23. @RequestMapping("/account.do")   
  24. public class AccountController {   
  25.   
  26.     @Autowired  
  27.     private AccountService accountService;   
  28.   
  29.     @RequestMapping(method = RequestMethod.GET)   
  30.     public void hello(HttpServletRequest request, HttpServletResponse response)   
  31.             throws Exception {   
  32.   
  33.         String username = ServletRequestUtils.getRequiredStringParameter(   
  34.                 request, "username");   
  35.         String password = ServletRequestUtils.getRequiredStringParameter(   
  36.                 request, "password");   
  37.         System.out.println(accountService.verify(username, password));   
  38.     }   
  39. }  
/**
 * 2010-1-23
 */
package org.zlex.spring.controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.ServletRequestUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.zlex.spring.service.AccountService;

/**
 * 
 * @author <a href="mailto:zlex.dongliang@gmail.com">梁栋</a>
 * @version 1.0
 * @since 1.0
 */
@Controller
@RequestMapping("/account.do")
public class AccountController {

	@Autowired
	private AccountService accountService;

	@RequestMapping(method = RequestMethod.GET)
	public void hello(HttpServletRequest request, HttpServletResponse response)
			throws Exception {

		String username = ServletRequestUtils.getRequiredStringParameter(
				request, "username");
		String password = ServletRequestUtils.getRequiredStringParameter(
				request, "password");
		System.out.println(accountService.verify(username, password));
	}
}


分段详述：

Java代码 复制代码
  1. @Controller  
  2. @RequestMapping("/account.do")   
@Controller
@RequestMapping("/account.do")


这两行注解，@Controller是告诉Spring容器，这是一个控制器类，@RequestMapping("/account.do")是来定义该控制器对应的请求路径（/account.do）

Java代码 复制代码
  1. <span style=
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