spring MVC笔记

在系列（3）中我们介绍了请求是如何映射到一个action上的，下一步当然是如何获取到请求中的数据，这就引出了本篇所要讲的内容—数据绑定。

首先看一下都有哪些绑定数据的注解：

1.@RequestParam，绑定单个请求数据，可以是URL中的数据，表单提交的数据或上传的文件；
2.@PathVariable，绑定URL模板变量值；
3.@CookieValue，绑定Cookie数据；
4.@RequestHeader，绑定请求头数据；
5.@ModelAttribute，绑定数据到Model；
6.@SessionAttributes，绑定数据到Session；
7.@RequestBody，用来处理Content-Type不是application/x-www-form-urlencoded编码的内容，例如application/json, application/xml等；
8.@RequestPart，绑定“multipart/data”数据，并可以根据数据类型进项对象转换；

下面我们来看如何使用：

1.@RequestParam：

为了验证文件绑定我们需要先做以下工作：

a.把commons-fileupload-1.3.1.jar和commons-io-2.4.jar两个jar包添加到我们项目。

b.配置我们项目中的springservlet-config.xml文件使之支持文件上传，内容如下：

[xml] view plain copy print ?

<code class="hljs xml" style='padding: 10px; color: rgb(220, 220, 220); line-height: 1.4; font-family: Menlo, Monaco, Consolas, "Courier New", monospace; font-size: 13px; background-color: rgb(63, 63, 63);'>
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<property name="maxUploadSize">
<value>1048576</value>
</property>
<property name="defaultEncoding">
<value>UTF-8</value>
</property>
</bean></code>

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">

</property>

</property></bean>

其中maxUploadSize用于限制上传文件的最大大小，也可以不做设置，这样就代表上传文件的大小木有限制。defaultEncoding用于设置上传文件的编码格式，用于解决上传的文件中文名乱码问题。

下面就看具体如何使用：

添加一个DataBindController，里面有2个paramBind的action分别对应get和post请求：

[java] view plain copy print ?

<code class="hljs less" style='padding: 10px; color: rgb(220, 220, 220); line-height: 1.4; font-family: Menlo, Monaco, Consolas, "Courier New", monospace; font-size: 13px; background-color: rgb(63, 63, 63);'>package com.demo.web.controllers;
import javax.servlet.http.HttpServletRequest;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.ServletRequestUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import org.springframework.web.servlet.ModelAndView;
@Controller
@RequestMapping(value = "/databind")
public class DataBindController {
@RequestMapping(value="/parambind", method = {RequestMethod.GET})
public ModelAndView paramBind(){
ModelAndView modelAndView = new ModelAndView();
modelAndView.setViewName("parambind");
return modelAndView;
}
@RequestMapping(value="/parambind", method = {RequestMethod.POST})
public ModelAndView paramBind(HttpServletRequest request, @RequestParam("urlParam") String urlParam, @RequestParam("formParam") String formParam, @RequestParam("formFile") MultipartFile formFile){
//如果不用注解自动绑定，我们还可以像下面一样手动获取数据
String urlParam1 = ServletRequestUtils.getStringParameter(request, "urlParam", null);
String formParam1 = ServletRequestUtils.getStringParameter(request, "formParam", null);
MultipartFile formFile1 = ((MultipartHttpServletRequest) request).getFile("formFile");
ModelAndView modelAndView = new ModelAndView();
modelAndView.addObject("urlParam", urlParam);
modelAndView.addObject("formParam", formParam);
modelAndView.addObject("formFileName", formFile.getOriginalFilename());
modelAndView.addObject("urlParam1", urlParam1);
modelAndView.addObject("formParam1", formParam1);
modelAndView.addObject("formFileName1", formFile1.getOriginalFilename());
modelAndView.setViewName("parambindresult");
return modelAndView;
}
}</code>

package com.demo.web.controllers;

import javax.servlet.http.HttpServletRequest;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.ServletRequestUtils;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.multipart.MultipartFile;

import org.springframework.web.multipart.MultipartHttpServletRequest;

import org.springframework.web.servlet.ModelAndView;

@Controller@RequestMapping(value = "/databind")

public class DataBindController {

@RequestMapping(value="/parambind", method = {RequestMethod.GET})

public ModelAndView paramBind(){

ModelAndView modelAndView = new ModelAndView();

modelAndView.setViewName("parambind");

return modelAndView;

}

@RequestMapping(value="/parambind", method = {RequestMethod.POST})

public ModelAndView paramBind(HttpServletRequest request, @RequestParam("urlParam") String urlParam, @RequestParam("formParam") String formParam, @RequestParam("formFile") MultipartFile formFile){

//如果不用注解自动绑定，我们还可以像下面一样手动获取数据

String urlParam1 = ServletRequestUtils.getStringParameter(request, "urlParam", null);

String formParam1 = ServletRequestUtils.getStringParameter(request, "formParam", null);

MultipartFile formFile1 = ((MultipartHttpServletRequest) request).getFile("formFile");

ModelAndView modelAndView = new ModelAndView();

modelAndView.addObject("urlParam", urlParam);

modelAndView.addObject("formParam", formParam);

modelAndView.addObject("formFileName", formFile.getOriginalFilename());

modelAndView.addObject("urlParam1", urlParam1);

modelAndView.addObject("formParam1", formParam1);

modelAndView.addObject("formFileName1", formFile1.getOriginalFilename());

modelAndView.setViewName("parambindresult");

return modelAndView;

}

在views文件夹中添加parambind.jsp和parambindresult.jsp两个视图，内容分别如下：

[html] view plain copy print ?

<code class="hljs erb" style='padding: 10px; color: rgb(220, 220, 220); line-height: 1.4; font-family: Menlo, Monaco, Consolas, "Courier New", monospace; font-size: 13px; background-color: rgb(63, 63, 63);'><%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="parambind?urlParam=AAA" method="post" enctype="multipart/form-data">
<input type="text" name="formParam" /><br/>
<input type="file" name="formFile" /><br/>
<input type="submit" value="Submit" />
</form>
</body>
</html></code>

<%@ page language="java" contentType="text/html; charset=UTF-8"

pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title></head><body>

</form> </body></html>

[html] view plain copy print ?

<code class="hljs dust" style='padding: 10px; color: rgb(220, 220, 220); line-height: 1.4; font-family: Menlo, Monaco, Consolas, "Courier New", monospace; font-size: 13px; background-color: rgb(63, 63, 63);'><%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
自动绑定数据：<br/><br/>
${urlParam}<br/>
${formParam}<br/>
${formFileName}<br/><br/><br/><br/>
手动获取数据：<br/><br/>
${urlParam1}<br/>
${formParam1}<br/>
${formFileName1}<br/>
</body>
</html<span class="hljs-tag" style="color: rgb

(227, 206, 171);">></code>

<%@ page language="java" contentType="text/html; charset=UTF-8"

自动绑定数据：

${urlParam}

${formParam}

${formFileName}

手动获取数据：

${urlParam1}

${formParam1}

${formFileName1} </body></html>

运行项目，输入内容，选择上传文件：

提交查看结果：

可以看到绑定的数据已经获取到了。

上面我们演示了如何把数据绑定到单个变量，但在实际应用中我们通常需要获取的是model对象，别担心，我们不需要把数据绑定到一个个变量然后在对model赋值，只需要把model加入相应的action参数（这里不需要指定绑定数据的注解）Spring MVC会自动进行数据转换并绑定到model对象上，一切就是这么简单。测试如下：

添加一个AccountModel类作为测试的model：

[java] view plain copy print ?

<code class="hljs java" style='padding: 10px; color: rgb(220, 220, 220); line-height: 1.4; font-family: Menlo, Monaco, Consolas, "Courier New", monospace; font-size: 13px; background-color: rgb(63, 63, 63);'>package com.demo.web.models;
public class AccountModel {
private String username;
private String password;
public void setUsername(String username){
this.username=username;
}
public void setPassword(String password){
this.password=password;
}
public String getUsername(){
return this.username;
}
public String getPassword(){
return this.password;
}
}</code>

package com.demo.web.models;

public class AccountModel {

private String username;

private String password;

public void setUsername(String username){

this.username=username;

}

public void setPassword(String password){

this.password=password;

}

public String getUsername(){

return this.username;

}

public String getPassword(){

return this.password;

}

在DataBindController里面添加2个modelAutoBind的action分别对应get和post请求：

[java] view plain copy print ?

<code class="hljs less" style='padding: 10px; color: rgb(220, 220, 220); line-height: 1.4; font-family: Menlo, Monaco, Consolas, "Courier New", monospace; font-size: 13px; background-color: rgb(63, 63, 63);'>@RequestMapping(value="/modelautobind", method = {RequestMethod.GET})
public String modelAutoBind(HttpServletRequest request, Model model){
model.addAttribute("accountmodel", new AccountModel());
return "modelautobind";
}
@RequestMapping(value="/modelautobind", method = {RequestMethod.POST})
public String modelAutoBind(HttpServletRequest request, Model model, AccountModel accountModel){
model.addAttribute("accountmodel", accountModel);
return "modelautobindresult";
}</code>

@RequestMapping(value="/modelautobind", method = {RequestMethod.GET})

public String modelAutoBind(HttpServletRequest request, Model model){

model.addAttribute("accountmodel", new AccountModel());

return "modelautobind";

}

@RequestMapping(value="/modelautobind", method = {RequestMethod.POST})

public String modelAutoBind(HttpServletRequest request, Model model, AccountModel accountModel){

model.addAttribute("accountmodel", accountModel);

return "modelautobindresult";

}

在views文件夹中添加modelautobind.jsp和modelautobindresult.jsp 2个视图用于提交数据和展示提交的数据：

modelautobind.jsp：

[html] view plain copy print ?

<code class="hljs erb" style='padding: 10px; color: rgb(220, 220, 220); line-height: 1.4; font-family: Menlo, Monaco, Consolas, "Courier New", monospace; font-size: 13px; background-color: rgb(63, 63, 63);'><%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<html>
<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title>
</head>
<body>
<form:form modelAttribute="accountmodel" method="post">
用户名：<form:input path="username"/><br/>
密码：<form:password path="password"/><br/>
<input type="submit" value="Submit" />
</form:form>
</body>
</html></code>

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