9.上传文件

1.客户端编程

为了上传文件，必须将HTML表格的enctype属性值设为multipart/form-data,

 <form action="action" enctype="multipart/form-data" method="post">
 Select a file <input type="file" name="fieldName">
 <input type="submit" value="Upload"> 4 </form>  

如果想上传多个文件，必须使用多个文件input元素

2.MultipartFile接口

在SpringMVC中处理已经上传的文件十分容易，上传到SpringMVC应用程序中的文件

会被包在一个MultipartFile对象中，你唯一的任务就是用类型为MultipartFile的属性编写一个

domain类

3.用Commons FileUpload上传文件

需要将两个jar文件复制到应用程序的WEB-INF/lib目录下，

commons-fileupload-x.y.jar

commons-io-x.y.jar

此外还需要在SpringMVC的配置文件中定义multipartResolver bean

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxUploadSize" value="200000">
</bean>

4.Domain类

package app11a.domain;
import java.io.Serializable;
import java.util.List;

import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import org.springframework.web.multipart.MultipartFile;

public class Product implements Serializable {
    private static final long serialVersionUID = 74458L;

    @NotNull
    @Size(min=1, max=10)
    private String name;

    private String description;
    private Float price;
    private List<MultipartFile> images;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getDescription() {
        return description;
    }
    public void setDescription(String description) {
        this.description = description;
    }
    public Float getPrice() {
        return price;
    }
    public void setPrice(Float price) {
        this.price = price;
    }
    public List<MultipartFile> getImages() {
        return images;
    }
    public void setImages(List<MultipartFile> images) {
        this.images = images;
    }
}

5.控制器

package app11a.controller;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;

import app11a.domain.Product;

@Controller
public class ProductController {

    private static final Log logger = LogFactory
            .getLog(ProductController.class);

    @RequestMapping(value = "/product_input")
    public String inputProduct(Model model) {
        model.addAttribute("product", new Product());
        return "ProductForm";
    }

    @RequestMapping(value = "/product_save")
    public String saveProduct(HttpServletRequest servletRequest,
            @ModelAttribute Product product, BindingResult bindingResult,
            Model model) {

        List<MultipartFile> files = product.getImages();

        List<String> fileNames = new ArrayList<String>();

        if (null != files && files.size() > 0) {
            for (MultipartFile multipartFile : files) {

                String fileName = multipartFile.getOriginalFilename();
                fileNames.add(fileName);

                File imageFile = new File(servletRequest.getServletContext()
                        .getRealPath("/image"), fileName);
                try {
                    multipartFile.transferTo(imageFile);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        // save product here
        model.addAttribute("product", product);
        return "ProductDetails";
    }

}

保存上传文件只需MultipartFile.transferTo（）方法

6.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:p="http://www.springframework.org/schema/p"
    xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd     
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="app11a.controller" />
    <context:component-scan base-package="app11a.formatter" />

    <mvc:annotation-driven conversion-service="conversionService" />

    <mvc:resources mapping="/css/**" location="/css/" />
    <mvc:resources mapping="/*.html" location="/" />
    <mvc:resources mapping="/image/**" location="/image/" />

    <bean id="viewResolver"
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/jsp/" />
        <property name="suffix" value=".jsp" />
    </bean>
    
    <bean id="messageSource" 
            class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
        <property name="basename" value="/WEB-INF/resource/messages" />
    </bean>
    
    <bean id="conversionService"
        class="org.springframework.format.support.FormattingConversionServiceFactoryBean">

        <property name="formatters">
            <set>
                <bean class="app11a.formatter.DateFormatter">
                    <constructor-arg type="java.lang.String" value="MM-dd-yyyy" />
                </bean>
            </set>
        </property>
    </bean>

    <bean id="multipartResolver"
            class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <property name="maxUploadSize" value="2000000"/>
    </bean>

</beans>

maxUploadSize:接受最大容量




7.JSP页面
ProductForm.jsp

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE HTML>
<html>
<head>
<title>Add Product Form</title>
<style type="text/css">@import url("<c:url value="/css/main.css"/>");</style>
</head>
<body>

<div id="global">
<form:form commandName="product" action="product_save" method="post" enctype="multipart/form-data">
    <fieldset>
        <legend>Add a product</legend>
        <p>
            <label for="name">Product Name: </label>
            <form:input id="name" path="name" cssErrorClass="error"/>
            <form:errors path="name" cssClass="error"/>
        </p>
        <p>
            <label for="description">Description: </label>
            <form:input id="description" path="description"/>
        </p>
        <p>
            <label for="price">Price: </label>
            <form:input id="price" path="price" cssErrorClass="error"/>
        </p>
        <p>
            <label for="image">Product Image: </label>
            <input type="file" name="images[0]"/>
        </p>
        <p id="buttons">
            <input id="reset" type="reset" tabindex="4">
            <input id="submit" type="submit" tabindex="5" 
                value="Add Product">
        </p>
    </fieldset>
</form:form>
</div>
</body>
</html>

ProductDetil.jsp

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE HTML>
<html>
<head>
<title>Save Product</title>
<style type="text/css">@import url("<c:url value="/css/main.css"/>");</style>
</head>
<body>
<div id="global">
    <h4>The product has been saved.</h4>
    <p>
        <h5>Details:</h5>
        Product Name: ${product.name}<br/>
        Description: ${product.description}<br/>
        Price: $${product.price}
        <p>Following files are uploaded successfully.</p>
        <ol>
        <c:forEach items="${product.images}" var="image">
            <li>${image.originalFilename}
            <img width="100" src="<c:url value="/image/"/>
            ${image.originalFilename}"/>
            </li>
        </c:forEach>
        </ol>
    </p>
</div>
</body>
</html>

8.测试应用

http://localhost:8080/app11a/product_save