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SpringMVC基础入门，创建一个HelloWorld程序

2024-08-28 02:30:23   224人阅读

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

一、SpringMVC基础入门，创建一个HelloWorld程序

　　1.首先，导入SpringMVC需要的jar包。

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　　2.添加Web.xml配置文件中关于SpringMVC的配置

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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

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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

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　　6.编写Controller代码

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@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

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//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

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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里编写方法

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//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

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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));
}

　七、向前台传递参数

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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";
}

　　前台可在Request域中取到"p"

　八、使用Ajax调用

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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";
}

　　前台用下面的Jquery代码调用

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$(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

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

　十、文件上传

　　1.需要导入两个jar包

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　　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.方法代码

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@RequestMapping(value=http://www.mamicode.com/"/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

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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>

　十一、使用@RequestParam注解指定参数的name

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@Controller
@RequestMapping("/test")
public class mvcController1 {
    @RequestMapping(value=http://www.mamicode.com/"/param")
    public String testRequestParam(@RequestParam(value=http://www.mamicode.com/"id") Integer id,
            @RequestParam(value=http://www.mamicode.com/"name")String name){
        System.out.println(id+" "+name);
        return "/hello";
    }   
}

　十二、RESTFul风格的SringMVC

　　1.RestController

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@Controller
@RequestMapping("/rest")
public class RestController {
    @RequestMapping(value=http://www.mamicode.com/"/user/{id}",method=RequestMethod.GET)
    public String get(@PathVariable("id") Integer id){
        System.out.println("get"+id);
        return "/hello";
    }
     
    @RequestMapping(value=http://www.mamicode.com/"/user/{id}",method=RequestMethod.POST)
    public String post(@PathVariable("id") Integer id){
        System.out.println("post"+id);
        return "/hello";
    }
     
    @RequestMapping(value=http://www.mamicode.com/"/user/{id}",method=RequestMethod.PUT)
    public String put(@PathVariable("id") Integer id){
        System.out.println("put"+id);
        return "/hello";
    }
     
    @RequestMapping(value=http://www.mamicode.com/"/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

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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>

　　在前台可以用以下代码产生请求

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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>

　十三、返回json格式的字符串

　　1.导入以下jar包

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　　2.方法代码

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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;
    }
}

　十四、异常的处理

　　1.处理局部异常（Controller内）

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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.处理全局异常（所有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.另一种处理全局异常的方法

　　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

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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.拦截器执行顺序

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　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

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(未选中不用导入)

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　　2.编写实体类User并加上验证注解

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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表示时间必须是一个过去值

　　3.在jsp中使用SpringMVC的form表单

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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对应name

　　4.Controller中代码

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

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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.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

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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"/>

　　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

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　　2.User实体类

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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类

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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目录下创建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中进行一些配置，防止SpringMVC和SpringIOC对同一个对象的管理重合

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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>

　十八、SpringMVC详细运行流程图

技术分享

　十九、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。

SpringMVC基础入门，创建一个HelloWorld程序


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