公司項目通過前后端分離，提出一個需求。用戶信息被node.js存儲在request的header中，而后台使用的是Spring MVC通過@RequestBody注釋，只能封裝請求參數，header中的參數無法被封裝成用戶對象。
解決方法：Spring MVC提供動態修改被訪問的controller參數。
controller類
package com.ch.controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import org.springframework.web.servlet.ModelAndView; import com.ch.user.User; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.util.HashMap; import java.util.Map; /** * Created by CH on 2017/12/6/006. */ @RestController @RequestMapping("/admin") public class AdminController { /** *訪問initAPI時，User會自動組裝，組裝函數在resolver類
*/ @RequestMapping("/init") public ModelAndView init(HttpServletRequest request, HttpServletResponse response, User user){ return new ModelAndView("", new HashMap<String, Object>()); } } 自定義用戶類 package com.ch.user; /** * Created by CH on 2017/12/6/006. */ public class User { private String name; private Integer age; public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } } resolver類 package com.ch.resolver; import com.ch.user.User; import org.springframework.core.MethodParameter; import org.springframework.web.bind.support.WebArgumentResolver; import org.springframework.web.context.request.NativeWebRequest; import javax.servlet.http.HttpServletRequest; /** * Created by CH on 2017/12/7/007.
* 訪問controller中任何函數都會觸發下面方法 */ public class BeanArgumentResolver implements WebArgumentResolver{ @Override public Object resolveArgument(MethodParameter methodParameter, NativeWebRequest webRequest) throws Exception { //methodParameter就是訪問方法的參數對象，以下判斷為被訪問的方法參數不為空，並且被訪問的參數為用戶參數 if(methodParameter.getParameterType() != null && methodParameter.getParameterType().equals(User.class)){ HttpServletRequest request = webRequest.getNativeRequest(HttpServletRequest.class); //獲取request中的請求對象，從header中獲取，並封裝返回 User user = new User(); if(request != null){ String name = request.getHeader("name"); String age = request.getHeader("age"); if(name != null && !name.isEmpty()){ user.setName(name); } if(age != null && !age.isEmpty()){ user.setAge(Integer.parseInt(age)); } } return user; } return UNRESOLVED; } }
applicationContext.xml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:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:mvc="http://www.springframework.org/schema/c" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd"> <!-- 自動掃描與裝配 Service 和 Dao 層的 Bean --> <context:component-scan base-package="com.ch"> <context:exclude-filter type="regex" expression=".*Controller$"/> </context:component-scan> </beans> dispatcher-servlet.xml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:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd 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-4.2.xsd"> <!-- 此配置文件是配置需要掃描的控制層類 --> <context:component-scan base-package="com.ch.controller"/> <mvc:annotation-driven> <mvc:argument-resolvers> <bean class="com.ch.resolver.BeanArgumentResolver" /> </mvc:argument-resolvers> </mvc:annotation-driven> </beans> web.xml配置 <?xml version="1.0" encoding="UTF-8"?> <web-app 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_3_0.xsd" version="3.0"> <context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath*:applicationContext*.xml</param-value> </context-param> <listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener> <servlet> <servlet-name>dispatcher</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <!-- 顯式指定 Spring MVC 控制器的配置文件 --> <param-value>classpath:/dispatcher-servlet.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>dispatcher</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <!-- 配置編碼方式過濾器,注意:要配置在所有過濾器的前面 --> <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> </web-app> maven配置 <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/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.helloword</groupId> <artifactId>helloword</artifactId> <version>1.0-SNAPSHOT</version> <name>helloword</name>
<properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <spring.version>4.3.10.RELEASE</spring.version> </properties> <dependencies> <!-- Spring Framework - Begin --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aspects</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context-support</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-expression</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-instrument</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-instrument-tomcat</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jms</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-messaging</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-oxm</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-tx</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc-portlet</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-websocket</artifactId> <version>${spring.version}</version> </dependency> <!-- Spring Framework - End -->
<!-- Servlet - Begin --> <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api --> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>3.1.0</version> <scope>provided</scope> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> <!-- Servlet - End --> </dependencies> </project>