springmvc 基礎內容

時間 2019-11-10

原文原文鏈接

springmvc 基礎內容java

1.須要導入的包
   commons-logging-1.2.jar
   spring-aop-4.1.6.RELEASE.jar
   spring-beans-4.1.6.RELEASE.jar
   spring-context-4.1.6.RELEASE.jar
   spring-core-4.1.6.RELEASE.jar
   spring-expression-4.1.6.RELEASE.jar
   spring-web-4.1.6.RELEASE.jar
   spring-webmvc-4.1.6.RELEASE.jar
或者經過maven中配置web

   <dependency>
       <groupId>org.springframework</groupId>
       <artifactId>spring-webmvc</artifactId>
       <version>4.3.1.RELEASE</version>
   </dependency>
   <dependency>
       <groupId>org.springframework</groupId>
       <artifactId>spring-web</artifactId>
       <version>4.3.1.RELEASE</version>
   </dependency>ajax

2.添加Web.xml配置文件中關於SpringMVC的配置spring

   <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
              <param-name>contextConfigLocation</param-name>
              <param-value>classpath:springmvc-servlet.xml</param-value>
          </init-param>
   </servlet>
   <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
   </servlet-mapping>express

3.在src下添加springmvc-servlet.xml配置文件
<?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-4.1.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd">


<context:component-scan base-package="test.SpringMVC"/>


<mvc:default-servlet-handler />


<mvc:annotation-driven />


<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
id="internalResourceViewResolver">

<property name="prefix" value="/WEB-INF/jsp/" />

<property name="suffix" value=".jsp" />
</bean>
</beans>json

4.在WEB-INF文件夾下建立名爲jsp的文件夾，用來存放jsp視圖。建立一個hello.jsp，在body中添加「Hello World」。api

5.創建包及Controller瀏覽器

6.編寫Controller代碼
   @Controller
   @RequestMapping("/mvc")
   public class mvcController {

   @RequestMapping("/hello")
   public String hello(){
       return "hello";
   }
   }spring-mvc

7.啓動服務器，鍵入 http://localhost:8080/項目名/mvc/hello服務器

2、配置解析

　　1.Dispatcherservlet
　　DispatcherServlet是前置控制器，配置在web.xml文件中的。
攔截匹配的請求，Servlet攔截匹配規則要自已定義，把攔截下來的請求，依據相應的規則分發到目標Controller來處理，是配置spring MVC的第一步。

　　2.InternalResourceViewResolver
　　視圖名稱解析器

　　3.以上出現的註解
　　@Controller 負責註冊一個bean 到spring 上下文中
　　@RequestMapping 註解爲控制器指定能夠處理哪些 URL 請求

3、SpringMVC經常使用註解

　　@Controller
　　負責註冊一個bean 到spring 上下文中

　　@RequestMapping
　　註解爲控制器指定能夠處理哪些 URL 請求

　　@RequestBody
　　該註解用於讀取Request請求的body部分數據，使用系統默認配置的HttpMessageConverter進行解析，
而後把相應的數據綁定到要返回的對象上 ,再把HttpMessageConverter返回的對象數據綁定到 controller中方法的參數上

　　@ResponseBody
　　該註解用於將Controller的方法返回的對象，經過適當的HttpMessageConverter轉換爲指定格式後，寫入到Response對象的body數據區

　　@ModelAttribute 　　　
　　在方法定義上使用 @ModelAttribute 註解：Spring MVC 在調用目標處理方法前，會先逐個調用在方法級上標註了@ModelAttribute 的方法
　　在方法的入參前使用 @ModelAttribute 註解：能夠從隱含對象中獲取隱含的模型數據中獲取對象，再將請求參數 –綁定到對象中，再傳入入參將方法入參對象添加到模型中

　　@RequestParam　
　　在處理方法入參處使用 @RequestParam 能夠把請求參數傳遞給請求方法

　　@PathVariable
　　綁定 URL 佔位符到入參

　　@ExceptionHandler
　　註解到方法上，出現異常時會執行該方法

　　@ControllerAdvice
　　使一個Contoller成爲全局的異常處理類，類中用@ExceptionHandler方法註解的方法能夠處理全部Controller發生的異常

4、自動匹配參數
   //match automatically
   @RequestMapping("/person")
   public String toPerson(String name,double age){
   System.out.println(name+" "+age);
   return "hello";
   }

5、自動裝箱

　　1.編寫一個Person實體類
   package test.SpringMVC.model;
   public class Person {
   public String getName() {
       return name;
   }
   public void setName(String name) {
       this.name = name;
   }
   public int getAge() {
       return age;
   }
   public void setAge(int age) {
       this.age = age;
   }
   private String name;
   private int age;

   }
2.在Controller裏編寫方法
   //boxing automatically
   @RequestMapping("/person1")
   public String toPerson(Person p){
   System.out.println(p.getName()+" "+p.getAge());
   return "hello";
   }

6、使用InitBinder來處理Date類型的參數
   //the parameter was converted in initBinder
   @RequestMapping("/date")
   public String date(Date date){
   System.out.println(date);
   return "hello";
   }

   //At the time of initialization,convert the type "String" to type "date"
   @InitBinder
   public void initBinder(ServletRequestDataBinder binder){
   binder.registerCustomEditor(Date.class, new CustomDateEditor(new SimpleDateFormat("yyyy-MM-dd"),
       true));
   }

7、向前臺傳遞參數
   //pass the parameters to front-end
   @RequestMapping("/show")
   public String showPerson(Map<String,Object> map){
   Person p =new Person();
   map.put("p", p);
   p.setAge(20);
   p.setName("jayjay");
   return "show";
   }
   //前臺可在Request域中取到"p"

8、使用Ajax調用
   //pass the parameters to front-end using ajax
   @RequestMapping("/getPerson")
   public void getPerson(String name,PrintWriter pw){
   pw.write("hello,"+name);
   }
   @RequestMapping("/name")
   public String sayHello(){
   return "name";
   }
   　　前臺用下面的Jquery代碼調用
   $(function(){
   $("#btn").click(function(){
   $.post("mvc/getPerson",{name:$("#name").val()},function(data){
       alert(data);
       });
   });
   });
9、在Controller中使用redirect方式處理請求
   //redirect
   @RequestMapping("/redirect")
   public String redirect(){
   return "redirect:hello";
   }

10、文件上傳

1.須要導入兩個jar包
   commons-fileupload-1.3.1.jar
   commons-io-2.4.jar
　2.在SpringMVC配置文件中加入
   
   <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
   <property name="maxUploadSize" value="102400000"></property>
   </bean>

3.方法代碼
   @RequestMapping(value="/upload",method=RequestMethod.POST)
   public String upload(HttpServletRequest req) throws Exception{
   MultipartHttpServletRequest mreq = (MultipartHttpServletRequest)req;
   MultipartFile file = mreq.getFile("file");
   String fileName = file.getOriginalFilename();
   SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
   FileOutputStream fos = new FileOutputStream(req.getSession().getServletContext().getRealPath("/")+
       "upload/"+sdf.format(new Date())+fileName.substring(fileName.lastIndexOf('.')));
   fos.write(file.getBytes());
   fos.flush();
   fos.close();

   return "hello";
   }

　4.前臺form表單
   <form action="mvc/upload" method="post" enctype="multipart/form-data">
   <input type="file" name="file"><br>
   <input type="submit" value="submit">
   </form>

11、使用@RequestParam註解指定參數的name
   @Controller
   @RequestMapping("/test")
   public class mvcController1 {
   @RequestMapping(value="/param")
   public String testRequestParam(@RequestParam(value="id") Integer id,
       @RequestParam(value="name")String name){
       System.out.println(id+" "+name);
       return "/hello";
   }
   }

12、RESTFul風格的SringMVC
   　　1.RestController
   @Controller
   @RequestMapping("/rest")
   public class RestController {
   @RequestMapping(value="/user/{id}",method=RequestMethod.GET)
   public String get(@PathVariable("id") Integer id){
       System.out.println("get"+id);
       return "/hello";
   }

   @RequestMapping(value="/user/{id}",method=RequestMethod.POST)
   public String post(@PathVariable("id") Integer id){
       System.out.println("post"+id);
       return "/hello";
   }

   @RequestMapping(value="/user/{id}",method=RequestMethod.PUT)
   public String put(@PathVariable("id") Integer id){
       System.out.println("put"+id);
       return "/hello";
   }

   @RequestMapping(value="/user/{id}",method=RequestMethod.DELETE)
   public String delete(@PathVariable("id") Integer id){
       System.out.println("delete"+id);
       return "/hello";
   }

   }

2.form表單發送put和delete請求
　　在web.xml中配置
   
   <filter>
   <filter-name>HiddenHttpMethodFilter</filter-name>
   <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
   </filter>
   <filter-mapping>
   <filter-name>HiddenHttpMethodFilter</filter-name>
   <url-pattern>/*</url-pattern>
   </filter-mapping>

在前臺能夠用如下代碼產生請求
   <form action="rest/user/1" method="post">
   <input type="hidden" name="_method" value="PUT">
   <input type="submit" value="put">
   </form>

   <form action="rest/user/1" method="post">
   <input type="submit" value="post">
   </form>

   <form action="rest/user/1" method="get">
   <input type="submit" value="get">
   </form>

   <form action="rest/user/1" method="post">
   <input type="hidden" name="_method" value="DELETE">
   <input type="submit" value="delete">
   </form>

十3、返回json格式的字符串
   1.導入如下jar包
   jackson-annotations-2.2.1.jar
   jackson-core-2.2.1.jar
   jackson-databind-2.2.1.jar

   2.2.方法代碼
   @Controller
   @RequestMapping("/json")
   public class jsonController {

   @ResponseBody
   @RequestMapping("/user")
   public User get(){
       User u = new User();
       u.setId(1);
       u.setName("jayjay");
       u.setBirth(new Date());
       return u;
   }
   }

十4、異常的處理

　　1.處理局部異常（Controller內）
   @ExceptionHandler
   public ModelAndView exceptionHandler(Exception ex){
   ModelAndView mv = new ModelAndView("error");
   mv.addObject("exception", ex);
   System.out.println("in testExceptionHandler");
   return mv;
   }

   @RequestMapping("/error")
   public String error(){
   int i = 5/0;
   return "hello";
   }

2.處理全局異常（全部Controller）
   @ControllerAdvice
   public class testControllerAdvice {
   @ExceptionHandler
   public ModelAndView exceptionHandler(Exception ex){
       ModelAndView mv = new ModelAndView("error");
       mv.addObject("exception", ex);
       System.out.println("in testControllerAdvice");
       return mv;
   }
   }

　　3.另外一種處理全局異常的方法
　　在SpringMVC配置文件中配置
   
   <bean class="org.springframework.web.servlet.handler.SimpleMappingExceptionResolver">
   <property name="exceptionMappings">
       <props>
       <prop key="java.lang.ArithmeticException">error</prop>
       </props>
   </property>
   </bean>

　十5、設置一個自定義攔截器
　　1.建立一個MyInterceptor類，並實現HandlerInterceptor接口

public class MyInterceptor implements HandlerInterceptor {

   @Override
   public void afterCompletion(HttpServletRequest arg0,
       HttpServletResponse arg1, Object arg2, Exception arg3)
       throws Exception {
       System.out.println("afterCompletion");
   }

   @Override
   public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1,
       Object arg2, ModelAndView arg3) throws Exception {
       System.out.println("postHandle");
   }

   @Override
   public boolean preHandle(HttpServletRequest arg0, HttpServletResponse arg1,
       Object arg2) throws Exception {
       System.out.println("preHandle");
       return true;
   }

   }
　2.在SpringMVC的配置文件中配置
   
   <mvc:interceptors>
   <mvc:interceptor>
       <mvc:mapping path="/mvc/**"/>
       <bean class="test.SpringMVC.Interceptor.MyInterceptor"></bean>
   </mvc:interceptor>
   </mvc:interceptors>

　3.攔截器執行順序
   1. FirstInterceptor#preHandle
   2. HandlerAdapter#handle
   3. FirstInterceptor#postHandle
   4. DispatcherServlet#render
   5. FirstInterceptor#afterCompletion

十6、表單的驗證（使用Hibernate-validate）及國際化

　　1.導入Hibernate-validate須要的jar包
   classmate-1.0.0.jar
   jboss-loggin-3.1.3.GA.jar
   validation-api-1.1.0.Final.jar
   hibernate-validator-5.1.3.Final.jar
   hibernate-validator-annotation-proce

2.編寫實體類User並加上驗證註解
   public class User {
   public int getId() {
       return id;
   }
   public void setId(int id) {
       this.id = id;
   }
   public String getName() {
       return name;
   }
   public void setName(String name) {
       this.name = name;
   }
   public Date getBirth() {
       return birth;
   }
   public void setBirth(Date birth) {
       this.birth = birth;
   }
   @Override
   public String toString() {
       return "User [id=" + id + ", name=" + name + ", birth=" + birth + "]";
   }
   private int id;
   @NotEmpty
   private String name;

   @Past
   @DateTimeFormat(pattern="yyyy-MM-dd")
   private Date birth;
   }
   //　ps:@Past表示時間必須是一個過去值

　　3.在jsp中使用SpringMVC的form表單
   <form:form action="form/add" method="post" modelAttribute="user">
   id:<form:input path="id"/><form:errors path="id"/><br>
   name:<form:input path="name"/><form:errors path="name"/><br>
   birth:<form:input path="birth"/><form:errors path="birth"/>
   <input type="submit" value="submit">
   </form:form>
   //ps:path對應name

4.Controller中代碼
   @Controller
   @RequestMapping("/form")
   public class formController {
   @RequestMapping(value="/add",method=RequestMethod.POST)
   public String add(@Valid User u,BindingResult br){
       if(br.getErrorCount()>0){
       return "addUser";
       }
       return "showUser";
   }

   @RequestMapping(value="/add",method=RequestMethod.GET)
   public String add(Map<String,Object> map){
       map.put("user",new User());
       return "addUser";
   }
   }
    　ps:
   　　1.由於jsp中使用了modelAttribute屬性，因此必須在request域中有一個"user".
   　　2.@Valid 表示按照在實體上標記的註解驗證參數
   　　3.返回到原頁面錯誤信息回回顯，表單也會回顯
5.錯誤信息自定義
   　　在src目錄下添加locale.properties
   NotEmpty.user.name=name can't not be empty
   Past.user.birth=birth should be a past value
   DateTimeFormat.user.birth=the format of input is wrong
   typeMismatch.user.birth=the format of input is wrong
   typeMismatch.user.id=the format of input is wrong

　在SpringMVC配置文件中配置
   
   <bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">
   <property name="basename" value="locale"></property>
   </bean>

　　6.國際化顯示

　　在src下添加locale_zh_CN.properties
username=帳號
password=密碼

　　 locale.properties中添加
username=user name
password=password

建立一個locale.jsp
   <body>
   <fmt:message key="username"></fmt:message>
   <fmt:message key="password"></fmt:message>
   </body>
在SpringMVC中配置
   
   <mvc:view-controller path="/locale" view-name="locale"/>

　讓locale.jsp在WEB-INF下也能直接訪問
　　最後，訪問locale.jsp，切換瀏覽器語言，能看到帳號和密碼的語言也切換了

　十7、壓軸大戲--整合SpringIOC和SpringMVC
　1.建立一個test.SpringMVC.integrate的包用來演示整合，並建立各種
   User.java
   UserController.java
   UserService.java

　2.User實體類
   public class User {
   public int getId() {
       return id;
   }
   public void setId(int id) {
       this.id = id;
   }
   public String getName() {
       return name;
   }
   public void setName(String name) {
       this.name = name;
   }
   public Date getBirth() {
       return birth;
   }
   public void setBirth(Date birth) {
       this.birth = birth;
   }
   @Override
   public String toString() {
       return "User [id=" + id + ", name=" + name + ", birth=" + birth + "]";
   }
   private int id;
   @NotEmpty
   private String name;

   @Past
   @DateTimeFormat(pattern="yyyy-MM-dd")
   private Date birth;
   }

3.UserService類
   @Component
   public class UserService {
   public UserService(){
       System.out.println("UserService Constructor...\n\n\n\n\n\n");
   }

   public void save(){
       System.out.println("save");
   }
   }

4.UserController
   @Controller
   @RequestMapping("/integrate")
   public class UserController {
   @Autowired
   private UserService userService;

   @RequestMapping("/user")
   public String saveUser(@RequestBody @ModelAttribute User u){
       System.out.println(u);
       userService.save();
       return "hello";
   }
   }

　　5.Spring配置文件
　　在src目錄下建立SpringIOC的配置文件applicationContext.xml

   <?xml version="1.0" encoding="UTF-8"?>
   <beans xmlns="http://www.springframework.org/schema/beans"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/util
       http://www.springframework.org/schema/util/spring-util-4.0.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       "
       xmlns:util="http://www.springframework.org/schema/util"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       >
   <context:component-scan base-package="test.SpringMVC.integrate">
       <context:exclude-filter type="annotation"
       expression="org.springframework.stereotype.Controller"/>
       <context:exclude-filter type="annotation"
       expression="org.springframework.web.bind.annotation.ControllerAdvice"/>
   </context:component-scan>

   </beans>

在Web.xml中添加配置
   
   <listener>
   <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
   </listener>
   <context-param>
   <param-name>contextConfigLocation</param-name>
   <param-value>classpath:applicationContext.xml</param-value>
   </context-param>

6.在SpringMVC中進行一些配置，防止SpringMVC和SpringIOC對同一個對象的管理重合
   
   <context:component-scan base-package="test.SpringMVC.integrate">
       <context:include-filter type="annotation"
       expression="org.springframework.stereotype.Controller"/>
       <context:include-filter type="annotation"
       expression="org.springframework.web.bind.annotation.ControllerAdvice"/>
   </context:component-scan>

十8、SpringMVC詳細運行流程圖

十9、SpringMVC與struts2的區別　　一、springmvc基於方法開發的，struts2基於類開發的。springmvc將url和controller裏的方法映射。映射成功後springmvc生成一個Handler對象，對象中只包括了一個method。方法執行結束，形參數據銷燬。springmvc的controller開發相似web service開發。　　二、springmvc能夠進行單例開發，而且建議使用單例開發，struts2經過類的成員變量接收參數，沒法使用單例，只能使用多例。　　三、通過實際測試，struts2速度慢，在於使用struts標籤，若是使用struts建議使用jstl。

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