作爲當前最火的mvc框架,優點:性能快,開發簡單,能很方便的支持restfull風格,可以直接返回json和xml格式。
一:簡單入門
<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.julyday</groupId>
<artifactId>spring_mvc</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>
<name>spring_mvc Maven Webapp</name>
<url>http://maven.apache.org</url>
<properties>
<commons-lang.version>2.6</commons-lang.version>
<slf4j.version>1.7.6</slf4j.version>
<spring.version>4.1.3.RELEASE</spring.version>
<jackson.version>2.5.4</jackson.version>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-framework-bom</artifactId>
<version>${spring.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-oxm</artifactId>
</dependency>
<dependency>
<groupId>commons-lang</groupId>
<artifactId>commons-lang</artifactId>
<version>${commons-lang.version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>${slf4j.version}</version>
<exclusions>
<exclusion>
<artifactId>slf4j-api</artifactId>
<groupId>org.slf4j</groupId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>${slf4j.version}</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
</dependency>
<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.1</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>${jackson.version}</version>
</dependency>
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.3</version>
</dependency>
<!-- xml格式輸出 -->
<dependency>
<groupId>com.thoughtworks.xstream</groupId>
<artifactId>xstream</artifactId>
<version>1.4.7</version>
</dependency>
</dependencies>
</project>
<?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"
metadata-complete="true">
<display-name>spring_mvc</display-name>
<!-- spring上下文 -->
<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>
<!-- 編碼utf-8 -->
<filter>
<filter-name>encodingFilter</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>encodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!-- Spring MVC的核心 DispatcherServlet-->
<servlet>
<servlet-name>mvc-dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring-mvc.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>mvc-dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
這裏我們還是用到了spring,雖然我們這個項目可以不整合spring,但是在實際的開發中不運用spring幾乎是不可能的。這裏我們把controller層交給springmvc處理,service層交給spring來處理,我們接下來的service層也是模擬出來的,不是真正的經過數據庫的<?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/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">
<!-- 使用@ Resource 、@ PostConstruct、@ PreDestroy -->
<!-- context:component-scan 會一併掃描,如果註解在base-package下使用可以去掉該註解 -->
<context:annotation-config />
<!-- 自動掃描 -->
<context:component-scan base-package="com.julyday">
<context:exclude-filter type="annotation"
expression="org.springframework.stereotype.Controller" />
</context:component-scan>
<!--<context:component-scan base-package="com.julyday.service.impl"/>-->
</beans>
這裏我們只模擬了service層,所有註釋的自動掃描也是可以的,但是最後還是用沒註釋的,以後我們如果是和數據庫相連的話是不會錯的。<?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/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">
<!-- 啓用Spring基於annotation的DI, 使用戶可以在Spring MVC中使用Spring的強大功能。 激活 @Required
@Autowired,JSR 250's @PostConstruct, @PreDestroy and @Resource 等標註 -->
<context:annotation-config />
<!-- DispatcherServlet上下文, 只管理@Controller類型的bean, 忽略其他型的bean, 如@Service -->
<context:component-scan base-package="com.julyday">
<context:include-filter type="annotation"
expression="org.springframework.stereotype.Controller" />
</context:component-scan>
<!-- <context:component-scan base-package="com.julyday.controller"/> -->
<!-- 擴充了註解驅動,可以將請求參數綁定到控制器參數 -->
<mvc:annotation-driven />
<!-- 靜態資源處理,resources, css, js, imgs -->
<!--<mvc:resources mapping="/resources/**" location="/resources/" />
<mvc:resources mapping="/js/**" location="/js/" />
<mvc:resources mapping="/images/**" location="/images/" />
<mvc:resources mapping="/css/**" location="/css/" /> -->
<!-- 容器默認的DefaultServletHandler處理 所有靜態內容與無RequestMapping處理的URL -->
<mvc:default-servlet-handler/>
<!-- 配置ViewResolver。 可以用多個ViewResolver。 使用order屬性排序。 InternalResourceViewResolver放在最後。 -->
<bean
class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
<property name="order" value="1"/>
<!-- 在沒有擴展名時即: "/user/1" 時的默認展現形式 -->
<!-- 以json作爲默認返回,方便調用,省去後綴.json -->
<!-- <property name="defaultContentType" value="application/json"></property>-->
<!-- 擴展名至mimeType的映射,即 /user.json => application/json -->
<property name="mediaTypes">
<map>
<!-- 告訴視圖解析器,返回的類型 /user/123.xml 將返回xml格式數據
/user/123.json 將返回json格式數據
/user/123.html 將返回html格式數據
favorParameter = false
/user/123?format=xml //將返回xml數據
/user/123?format=json //將返回json數據 -->
<entry key="json" value="application/json" />
<entry key="html" value="text/html" />
<entry key="xml" value="application/xml" />
</map>
</property>
<!-- 用於開啓 /userinfo/123?format=json 的支持 -->
<property name="favorParameter" value="true" />
<property name="defaultViews">
<list>
<!-- for application/json -->
<bean
class="org.springframework.web.servlet.view.json.MappingJackson2JsonView">
</bean>
<!-- for application/xml -->
<bean class="org.springframework.web.servlet.view.xml.MarshallingView">
<property name="marshaller">
<bean class="org.springframework.oxm.xstream.XStreamMarshaller" />
</property>
</bean>
</list>
</property>
<property name="ignoreAcceptHeader" value="true" />
</bean>
<bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass"
value="org.springframework.web.servlet.view.JstlView" />
<property name="prefix" value="/WEB-INF/jsp/" />
<property name="suffix" value=".jsp" />
</bean>
<!--200*1024*1024即200M resolveLazily屬性啓用是爲了推遲文件解析,以便捕獲文件大小異常 -->
<bean id="multipartResolver"
class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<property name="maxUploadSize" value="209715200" />
<property name="defaultEncoding" value="UTF-8" />
<property name="resolveLazily" value="true" />
</bean>
</beans>
在看springmvc配置之前,大家可以參考springmvc流程這篇文章,文章很詳細的講解了springmvc的流程,大家會知道HandlerMapping,HandlerAdapter,Controller,ViewResolver,View。HandlerMapping,HandlerAdapter
這個springmvc有默認的,我們不需要配置,Controller我們自己寫的邏輯,交給springmvc管理,ViewResolver這個就是需要我們配置的,在上文中,View視圖我們自己寫的,最後只要在controller裏面告訴springmvc,我們返回哪個視圖即可。package com.julyday.entity;
public class User {
private int id;
private String name;
private int age;
//getter setter
}
</pre><pre name="code" class="java">@Service("userService")
public class UserServiceImpl implements UserService{
@Override
public User findByid(Integer id) {
System.out.println("UserServiceImpl findByid"+id);
User u = new User("julyday",18);
u.setId(1);
return u;
}
@Override
public List<User> findAll() {
User u1 = new User("julyday",18);
u1.setId(1);
User u2 = new User("zhangsan",28);
u2.setId(2);
List<User> list = new ArrayList<User>();
list.add(u1);
list.add(u2);
return list;
}
}
@Controller
@RequestMapping("/user")
public class UserController {
private static Logger log = LoggerFactory.getLogger(UserController.class);
@Autowired
private UserService userService;
// 本方法將處理/user/hello
@RequestMapping(value = "hello")
public String hello() {
return "hello";
}
}
@Controller:告訴springmvc,管理這個controller。<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>hello.jsp</title>
</head>
<body>
this is julyday hello.jsp
</body>
</html>
return "hello";springmvc會更具我們的配置信息InternalResourceViewResolver,返回我們需要的實體hello.jsp。二:restfull風格的支持
@RequestMapping("/restful/{userId}")
public String restful(@PathVariable("userId") Integer id,
Map<String, Object> model) {
log.debug("UserController restful {}", id);
User user = userService.findByid(id);
model.put("user", user);
return "user/view";
}
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>view.jsp</title>
</head>
<body>
歡迎您:${user.name}
</body>
</html>
當然我們還可以這樣:
@RequestMapping("/restful2/{userId:[0-9]+}/{param}")
public String restful2(@PathVariable("userId") Integer id,@PathVariable("param")String param,
Map<String, Object> model){
log.debug("UserController restful id: {} and param: {}",id,param);
User user = userService.findByid(id);
model.put("user", user);
return "user/view";
}
userId我們用了正則的方式,我們還可以是多個參數的restfull。三:返回格式及文件下載
@RequestMapping("request")
public String request(HttpServletRequest request){
Integer id = Integer.valueOf(request.getParameter("userId"));
log.debug("UserController request {}",id);
User user = userService.findByid(id);
request.setAttribute("user", user);
return "user/view";
}
我們可以在參數中加入HttpServletRequest這樣,直接訪問request,response,session等servlet參數。@RequestMapping("all")
public @ResponseBody String findAll(){
List<User> list = userService.findAll();
return JSON.toJSONString(list);
}
@RequestMapping("all2")
public ResponseEntity<List<User>> findAll2(){
List<User> list = userService.findAll();
return new ResponseEntity<List<User>>(list, HttpStatus.OK);
}
@ResponseBody:通過適當的HttpMessageConverter轉換爲指定格式後,寫入到Response對象的body數據區。@RequestMapping(value="/upload", method=RequestMethod.GET)
public ModelAndView showUploadPage(ModelAndView model){
model.setViewName("upload");
return model;
}
@RequestMapping(value="/doUpload", method=RequestMethod.POST)
public String doUploadFile(@RequestParam("file") MultipartFile file) throws IOException{
if(!file.isEmpty()){
log.debug("doUpload file: {}", file.getOriginalFilename());
FileUtils.copyInputStreamToFile(file.getInputStream(), new File("c:\\temp\\", System.currentTimeMillis()+ file.getOriginalFilename()));
}
return "success";
}
四:過濾器
springmvc過濾器可以有兩種接口去實現:HandlerInterceptor,WebRequestInterceptor,兩種方式差不多public class MyInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request,
HttpServletResponse response, Object handler) throws Exception {
System.out.println("MyInterceptor preHandle...");
return true;
}
@Override
public void postHandle(HttpServletRequest request,
HttpServletResponse response, Object handler,
ModelAndView modelAndView) throws Exception {
if("/spring_mvc/user/upload/".equals(request.getRequestURI())){
modelAndView.setViewName("user/add");
}
System.out.println("MyInterceptor postHandle..."+handler.toString());
}
@Override
public void afterCompletion(HttpServletRequest request,
HttpServletResponse response, Object handler, Exception ex)
throws Exception {
System.out.println("MyInterceptor afterCompletion...");
}
}
public class WebInterceptor implements WebRequestInterceptor {
@Override
public void preHandle(WebRequest request) throws Exception {
System.out.println("WebInterceptor preHandle ...");
}
@Override
public void postHandle(WebRequest request, ModelMap model) throws Exception {
System.out.println("WebInterceptor postHandle ...");
}
@Override
public void afterCompletion(WebRequest request, Exception ex)
throws Exception {
System.out.println("WebInterceptor afterCompletion ...");
}
}
<mvc:interceptors>
<bean class="com.julyday.interceptor.MyInterceptor"></bean>
<mvc:interceptor>
<mvc:mapping path="/user/upload2"/>
<bean class="com.julyday.interceptor.WebInterceptor"></bean>
</mvc:interceptor>
</mvc:interceptors>
springmvc配置文件加上如上信息。