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SpringMVC学习笔记----

itxm 2021年05月25日 编程语言 326 0

一、SpringMVC基础入门,创建一个HelloWorld程序

1.首先,导入SpringMVC需要的jar包。

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'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

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

@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

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 –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

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('.'))); 
        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

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

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

(未选中不用导入)

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'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

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

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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