SpringMVC基礎入門，建立一個HelloWorld程序

時間  2019-12-08
標籤 springmvc 基礎 入門 建立 一個 helloworld 程序 欄目 Spring 简体版
原文   原文鏈接

ref:http://www.admin10000.com/document/6436.html　

1、SpringMVC基礎入門，建立一個HelloWorld程序

　　1.首先，導入SpringMVC須要的jar包。html

　　2.添加Web.xml配置文件中關於SpringMVC的配置java

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<!--configure the setting of springmvcDispatcherServlet and configure the mapping-->
< 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 >
       <!-- <load-on-startup>1</load-on-startup> -->
</ servlet >
 
< servlet-mapping >
     < servlet-name >springmvc</ servlet-name >
     < url-pattern >/</ url-pattern >
</ servlet-mapping >

　　3.在src下添加springmvc-servlet.xml配置文件web

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<? 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">                   
 
     <!-- scan the package and the sub package -->
     < context:component-scan base-package = "test.SpringMVC" />
 
     <!-- don't handle the static resource -->
     < mvc:default-servlet-handler />
 
     <!-- if you use annotation you must configure following setting -->
     < mvc:annotation-driven />
     
     <!-- configure the InternalResourceViewResolver -->
     < bean class = "org.springframework.web.servlet.view.InternalResourceViewResolver"
             id = "internalResourceViewResolver" >
         <!-- 前綴 -->
         < property name = "prefix" value = "/WEB-INF/jsp/" />
         <!-- 後綴 -->
         < property name = "suffix" value = ".jsp" />
     </ bean >
</ beans >

　　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」。ajax

　　5.創建包及Controller，以下所示spring

　　6.編寫Controller代碼express

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@Controller
@RequestMapping ( "/mvc" )
public class mvcController {
 
     @RequestMapping ( "/hello" )
     public String hello(){       
         return "hello" ;
     }
}

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

　2、配置解析

　　1.Dispatcherservlet瀏覽器

　　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。spring-mvc

　　2.InternalResourceViewResolver服務器

　　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

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//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

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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

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//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

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//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

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//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

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//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

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$( 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

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//redirect
@RequestMapping ( "/redirect" )
public String redirect(){
     return "redirect:hello" ;
}

　10、文件上傳

　　1.須要導入兩個jar包

　　2.在SpringMVC配置文件中加入

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<!-- upload settings -->
< bean id = "multipartResolver"  class = "org.springframework.web.multipart.commons.CommonsMultipartResolver" >
     < property name = "maxUploadSize" value = "102400000" ></ property >
</ bean >

　　3.方法代碼

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@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

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< 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

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@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

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@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

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<!-- configure the HiddenHttpMethodFilter,convert the post method to put or delete -->
< 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

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< 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

　　2.方法代碼

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@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）

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@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）

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@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

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<!-- configure SimpleMappingExceptionResolver -->
< bean class = "org.springframework.web.servlet.handler.SimpleMappingExceptionResolver" >
     < property name = "exceptionMappings" >
         < props >
             < prop key = "java.lang.ArithmeticException" >error</ prop >
         </ props >
     </ property >
</ bean >

　　error是出錯頁面

　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

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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

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<!-- interceptor setting -->
< 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

　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

(未選中不用導入)

　　2.編寫實體類User並加上驗證註解

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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

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< 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

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@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

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<!-- configure the locale resource -->
< 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

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< body >
   < fmt:message key = "username" ></ fmt:message >
   < fmt:message key = "password" ></ fmt:message >
</ body >

　　在SpringMVC中配置

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<!-- make the jsp page can be visited -->
< 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

　　2.User實體類

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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

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@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

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@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

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<? 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

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<!-- configure the springIOC -->
< 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

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<!-- scan the package and the sub package -->
     < 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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