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SpringMVC学习笔记

2017-03-28

SpringMVC学习笔记。一、SpringMVC基础入门,创建一个HelloWorld程序。

SpringMVC学习笔记

一、SpringMVC基础入门,创建一个HelloWorld程序

1.首先,导入SpringMVC需要的jar包。

图片描述

2.添加Web.xml配置文件中关于SpringMVC的配置

<!--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

<?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&#39;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">
        <!-- 前缀 -->
        <property name="prefix" value="/WEB-INF/jsp/" />
        <!-- 后缀 -->
        <property name="suffix" value=".jsp" />
    </bean>
</beans>

4.在WEB-INF文件夹下创建名为jsp的文件夹,用来存放jsp视图。创建一个hello.jsp,在body中添加“Hello World”。

5.建立包及Controller,如下所示

图片描述

6.编写Controller代码

@Controller
@RequestMapping("/mvc")
public class mvcController {

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

7.启动服务器,键入http://localhost:8080/项目名/mvc/hello

二、配置解析

1.Dispatcherservlet

DispatcherServlet是前置控制器,配置在web.xml文件中的。拦截匹配的请求,Servlet拦截匹配规则要自已定义,把拦截下来的请求,依据相应的规则分发到目标Controller来处理,是配置spring MVC的第一步。

2.InternalResourceViewResolver

视图名称解析器

3.以上出现的注解

  1. @Controller负责注册一个bean 到spring 上下文中
  2. @RequestMapping注解为控制器指定可以处理哪些 URL 请求. 三、SpringMVC常用注解

    @Controller

    负责注册一个bean 到spring 上下文中。

    @RequestMapping

    注解为控制器指定可以处理哪些 URL 请求。

    @RequestBody

    该注解用于读取Request请求的body部分数据,使用系统默认配置的HttpMessageConverter进行解析,然后把相应的数据绑定到要返回的对象上 ,再把HttpMessageConverter返回的对象数据绑定到controller中方法的参数上。

    @ResponseBody

    该注解用于将Controller的方法返回的对象,通过适当的HttpMessageConverter转换为指定格式后,写入到Response对象的body数据区。

    @ModelAttribute 

    • 在方法定义上使用@ModelAttribute注解:Spring MVC 在调用目标处理方法前,会先逐个调用在方法级上标注了@ModelAttribute的方法。
    • 在方法的入参前使用@ModelAttribute注解:可以从隐含对象中获取隐含的模型数据中获取对象,再将请求参数&ndash;绑定到对象中,再传入入参将方法入参对象添加到模型中。

      @RequestParam 

      在处理方法入参处使用@RequestParam可以把请求参 数传递给请求方法。

      @PathVariable

      绑定 URL 占位符到入参。

      @ExceptionHandler

      注解到方法上,出现异常时会执行该方法。

      @ControllerAdvice

      使一个Contoller成为全局的异常处理类,类中用@ExceptionHandler方法注解的方法可以处理所有Controller发生的异常。

      四、自动匹配参数
       //match automatically
          @RequestMapping("/person")
          public String toPerson(String name,double age){
              System.out.println(name+" "+age);
              return "hello";
       }
      五、自动装箱

      1.编写一个Person实体类

      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里编写方法

      //boxing automatically
          @RequestMapping("/person1")
          public String toPerson(Person p){
              System.out.println(p.getName()+" "+p.getAge());
              return "hello";
          }
      六、使用InitBinder来处理Date类型的参数
      //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));
          }
      七、向前台传递参数
      //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";
          }

      前台可在Request域中取到"p"

      八、使用Ajax调用
       //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";
          }

      前台用下面的Jquery代码调用:

      $(function(){
                    $("#btn").click(function(){
                        $.post("mvc/getPerson",{name:$("#name").val()},function(data){
                            alert(data);
                        });
                    });
                });
      九、在Controller中使用redirect方式处理请求
        //redirect 
          @RequestMapping("/redirect")
          public String redirect(){
              return "redirect:hello";
          }
      十、文件上传

      1.需要导入两个jar包

      图片描述

      2.在SpringMVC配置文件中加入

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

      3.方法代码:

      @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(&#39;.&#39;)));
              fos.write(file.getBytes());
              fos.flush();
              fos.close();
      
              return "hello";
          }

      4.前台form表单

        <form action="mvc/upload" method="post" enctype="multipart/form-data">
             <input type="file" name="file"><br>
             <input type="submit" value="submit">
        </form>
      十一、使用@RequestParam注解指定参数的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";
          }    
      }
      十二、RESTFul风格的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表单发送put和delete请求

      在web.xml中配置

      <!-- 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>

      在前台可以用以下代码产生请求

      <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>
      十三、返回json格式的字符串

      1.导入以下jar包

      图片描述

      2.方法代码

      @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;
          }
      }
      十四、异常的处理

      1.处理局部异常(Controller内)

          @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.处理全局异常(所有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.另一种处理全局异常的方法

      在SpringMVC配置文件中配置

          <!-- 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是出错页面.

      十五、设置一个自定义拦截器

      1.创建一个MyInterceptor类,并实现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

          <!-- interceptor setting -->
          <mvc:interceptors>
              <mvc:interceptor>
                  <mvc:mapping path="/mvc/**"/>
                  <bean class="test.SpringMVC.Interceptor.MyInterceptor"></bean>
              </mvc:interceptor>        
          </mvc:interceptors>

      3.拦截器执行顺序

      图片描述

      十六、表单的验证(使用Hibernate-validate)及国际化

      1.导入Hibernate-validate需要的jar包
      图片描述(未选中不用导入)
      图片描述

      2.编写实体类User并加上验证注解

      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表示时间必须是一个过去值

      3.在jsp中使用SpringMVC的form表单

      <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对应name

      4.Controller中代码

      @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.因为jsp中使用了modelAttribute属性,所以必须在request域中有一个"user".
        2.@Valid 表示按照在实体上标记的注解验证参数
        3.返回到原页面错误信息回回显,表单也会回显

      5.错误信息自定义

      在src目录下添加locale.properties

      NotEmpty.user.name=name can&#39;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

          <!-- configure the locale resource -->
          <bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">
              <property name="basename" value="locale"></property>
          </bean>

      6.国际化显示

      在src下添加locale_zh_CN.properties

      username=账号
      password=密码

      locale.properties中添加

      username=user name
      password=password

      创建一个locale.jsp

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

      在SpringMVC中配置

        <!-- make the jsp page can be visited -->
        <mvc:view-controller path="/locale" view-name="locale"/>

      让locale.jsp在WEB-INF下也能直接访问

      最后,访问locale.jsp,切换浏览器语言,能看到账号和密码的语言也切换了。

      十七、压轴大戏--整合SpringIOC和SpringMVC

      1.创建一个test.SpringMVC.integrate的包用来演示整合,并创建各类。
      图片描述

      2.User实体类

      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类

      @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目录下创建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

      <!-- 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中进行一些配置,防止SpringMVC和SpringIOC对同一个对象的管理重合。

      <!-- 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>
      十八、SpringMVC详细运行流程图

      图片描述

      十九、SpringMVC运行原理
      1. 客户端请求提交到DispatcherServlet;
      2. 由DispatcherServlet控制器查询一个或多个HandlerMapping,找到处理请求的Controller;
      3. DispatcherServlet将请求提交到Controller;
      4. Controller调用业务逻辑处理后,返回ModelAndView;
      5. DispatcherServlet查询一个或多个ViewResoler视图解析器,找到ModelAndView指定的视图;
      6. 视图负责将结果显示到客户端。 二十、SpringMVC与struts2的区别

        1、springmvc基于方法开发的,struts2基于类开发的。springmvc将url和controller里的方法映射。映射成功后springmvc生成一个Handler对象,对象中只包括了一个method。方法执行结束,形参数据销毁。springmvc的controller开发类似web service开发。
        2、springmvc可以进行单例开发,并且建议使用单例开发,struts2通过类的成员变量接收参数,无法使用单例,只能使用多例。
        3、经过实际测试,struts2速度慢,在于使用struts标签,如果使用struts建议使用jstl。

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