Web项目同时使用SpringMVC和Struts

最近负责的项目需要前后端分离，该项目使用的是struts框架，准备在该项目上先同时使用SpringMVC+Struts，然后再拆掉Struts。

整合SpringMVC步骤

首先在项目的web.xml
上添加DispatcherServlet以及Servlet映射路径关系。通过DispatcherServlet，提供了SpringMVC集中访问点。
<!-- 拦截匹配的请求 --> <servlet> <servlet-name>DispatcherServlet</servlet-name> <
servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param> <param-name>contextConfigLocation</param-name> <param-value>
classpath:spring/dispatcher-servlet.xml</param-value> </init-param> <!--
是否在启动时加载这个Servlet --> <load-on-startup>1</load-on-startup> </servlet> <
servlet-mapping> <servlet-name>DispatcherServlet</servlet-name> <!--
拦截匹配规则,拦截/,例如:/user/add--> <!-- SpringMVC的请求都改为以mvc结尾--> <url-pattern>/api/*</
url-pattern> </servlet-mapping>
dispathcer-servlet.xml用于定义视图文件位置、定义全局变量、定义拦截器、开启注解扫描等。
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns:xsi=
"http://www.w3.org/2001/XMLSchema-instance" xmlns=
"http://www.springframework.org/schema/beans" xmlns:context=
"http://www.springframework.org/schema/context" xmlns:mvc=
"http://www.springframework.org/schema/mvc" 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/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd" default-autowire=
"byName"> <!-- 视图解析器 --> <!-- 定义支持注解的HanlderMapping,用于分发请求 --> <
mvc:annotation-driven/> <!-- 设置使用注解的类所在的jar包 --> <context:component-scan
base-package="com.xx.xxxx.web.controller"/> </beans>
下面是web.xml几乎完整的配置
<?xml version="1.0" encoding="utf-8"?> <web-app version="2.4" xmlns=
"http://java.sun.com/xml/ns/j2ee" xmlns:xsi=
"http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=
"http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <display-name>xxxxxx</
display-name> <context-param> <param-name>logPath</param-name> <param-value>
/export/home/tomcat/logs/xxxx.xx.com</param-value> </context-param> <!-- spring
listener,自动装配ApplicationContext的配置信息 --> <listener> <listener-class>
org.springframework.web.context.ContextLoaderListener</listener-class> </
listener> <!-- spring config 部署spring-config.xml --> <context-param> <param-name
>contextConfigLocation</param-name> <param-value>classpath:spring-config.xml</
param-value> </context-param> <!-- spring character encoding,解决页面传过来的编码问题 --> <
filter> <filter-name>Character Encoding</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> </filter> <!-- 拦截匹配的请求 --> <servlet> <servlet-name>
DispatcherServlet</servlet-name> <servlet-class>
org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <
param-name>contextConfigLocation</param-name> <param-value>
classpath:spring/dispatcher-servlet.xml</param-value> </init-param> <!--
是否在启动时加载这个Servlet --> <load-on-startup>1</load-on-startup> </servlet> <
servlet-mapping> <servlet-name>DispatcherServlet</servlet-name> <!--
拦截匹配规则,拦截/,例如:/user/add--> <!-- SpringMVC的请求都改为以mvc结尾--> <url-pattern>/api/*</
url-pattern> </servlet-mapping> <!-- 指定欢迎页 --> <welcome-file-list> <welcome-file
>index.jsp</welcome-file> </welcome-file-list> <filter-mapping> <filter-name>
Character Encoding</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
<!-- struts配置 --> <!-- struts2 filter --> <filter> <filter-name>struts2</
filter-name> <filter-class>
org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</
filter-class> </filter> <filter-mapping> <filter-name>struts2</filter-name> <
url-pattern>*.action</url-pattern> <dispatcher>REQUEST</dispatcher> <dispatcher>
FORWARD</dispatcher> </filter-mapping> <filter-mapping> <filter-name>struts2</
filter-name> <url-pattern>*.html</url-pattern> <dispatcher>REQUEST</dispatcher>
<dispatcher>FORWARD</dispatcher> </filter-mapping> </web-app>
接下来在POM文件中引入SpringMVC依赖的jar包。
<!-- 添加springmvc依赖 --> <dependency> <groupId>org.springframework</groupId> <
artifactId>spring-webmvc</artifactId> <version>${spring.version}</version> </
dependency>
就这样，导致了依赖冲突，报错如下：
java.lang.NoSuchMethodError: org.springframework.core.GenericTypeResolver
.resolveTypeArguments

可以查看到GenericTypeResolver这个类在我项目中有2个！一个2.7.6版本，一个是3.1.1版本。发现是用于spring这个包冲突的，那么解决依赖冲突吧。
通过MAVEN的Show
Dependencies(Ctrl+Alt+Shift+U),对这个Spring包Exclude吧。这个有时候鼠标排除有bug，那么只能手动在POM文件里添加。
<exclusions> <exclusion> <artifactId>spring</artifactId> <groupId>
org.springframework</groupId> </exclusion> </exclusions>
推荐IDEA插件MAVEN Helper插件，听说很好用，然而不会，待学习，有会的小伙伴教教我=.=。

项目跑起来后又抱错，错误如下：
[org.springframework.web.servlet.DispatcherServlet] - Context initialization
failed org.springframework.beans.factory.BeanCreationException: Error creating
bean with name
'org.springframework.validation.beanvalidation.LocalValidatorFactoryBean#0':
Invocation of init method failed; nested exception is
javax.validation.ValidationException: Unable tocreate a Configuration, because
no Bean Validation provider could be found. Add a provider like Hibernate
Validator (RI)to your classpath. at
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:
1514) at
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:
521) at
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:
458) at org.springframework.beans.factory.support.AbstractBeanFactory$1.
getObject(AbstractBeanFactory.java:293) at
org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:
223) at
org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:
290) at
org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:
191) at
org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:
636) at
org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:
934) at
org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:
479) at
org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:
651) at
org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:
602) at
org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:
665) at
org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:
521) at
org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:
462) at
org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
at javax.servlet.GenericServlet.init(GenericServlet.java:158)
需要给项目中添加jsr303-validation包。MAVEN添加依赖
<dependency> <groupId>org.apache.bval</groupId> <artifactId>bval-jsr303</
artifactId> <version>0.5</version> </dependency>
一切正常，当我想通过@ResponseBody将对象自动转换为JSON返回时，报错了。
@Controller @RequestMapping("/home") public class HomeController {
@RequestMapping("/category") @ResponseBody public Category category() { return
new Category(1, "默认分类"); } /** * 为了方便先这么写这个类~ **/ public static class Category{
public int getCateId() { return cateId; } public void setCateId(int cateId) {
this.cateId = cateId; } public String getCateName() { return cateName; } public
void setCateName(String cateName) { this.cateName = cateName; } public int
cateId;public String cateName; public Category(int cateId, String cateName) {
this.cateId = cateId; this.cateName = cateName; } } }
报错描述是，页面状态码为406 Not Accepatable。
The resource identified by this request is only capable of generating responses
with characteristics not acceptable according to the request "accept" headers
().
406解析：HTTP 协议中的 406 Not Acceptable 状态码表示客户端错误，指代服务器端无法提供与 Accept-Charset 以及
Accept-Language 消息头指定的值相匹配的响应。

发现HTTP Response的content-type是text/xml。而不是application/json。

解决方法，需要我们添加POM依赖：
<!-- 解决注解返回JSON,抛出406错误 --> <dependency> <groupId>com.fasterxml.jackson.core</
groupId> <artifactId>jackson-core</artifactId> <version>2.7.9</version> </
dependency> <dependency> <groupId>org.codehaus.jackson</groupId> <artifactId>
jackson-core-asl</artifactId> <version>1.9.13</version> </dependency> <
dependency> <groupId>org.codehaus.jackson</groupId> <artifactId>
jackson-mapper-asl</artifactId> <version>1.9.13</version> </dependency> <
dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>
jackson-annotations</artifactId> <version>2.7.9</version> </dependency> <
dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>
jackson-databind</artifactId> <version>2.7.9.1</version> </dependency>
到此第一步工作完成。

参考链接：
Validation错误 <https://blog.csdn.net/xlgen157387/article/details/49799973>
Web项目同时使用Struts2和SpringMVC
<https://blog.csdn.net/accountwcx/article/details/46809467>
Spring MVC的web.xml配置详解
<https://blog.csdn.net/u010796790/article/details/52098258>
@ResponseBody返回json 报406 not acceptable
<https://blog.csdn.net/zhujianli1314/article/details/50697967>

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