MD5加密 springMVC文件上传显示示例

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Spring MVC

属于SpringFrameWork的后续产品，已经融合在Spring Web Flow里面。Spring 框架提供了构建 Web 应用程序的全功能 MVC 模块。使用 Spring 可插入的 MVC 架构，从而在使用Spring进行WEB开发时，可以选择使用Spring的SpringMVC框架或集成其他MVC开发框架，如Struts1(现在一般不用)，Struts2(一般老项目使用)等。

MD5

消息摘要算法（英语：MD5 Message-Digest Algorithm），一种被广泛使用的密码散列函数，可以产生出一个128位（16字节）的散列值（hash value），用于确保信息传输完整一致。MD5由美国密码学家罗纳德·李维斯特（Ronald Linn Rivest）设计，于1992年公开，用以取代MD4算法。

pom.xml

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<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>
    <packaging>war</packaging>

    <name>FileUpload</name>
    <groupId>com</groupId>
    <artifactId>FileUpload</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.8.12</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>3.2.13.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.0.1</version>
            <scope>provided</scope>
        </dependency>

        <!--文件上传  必备-->
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.4</version>
        </dependency>
        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.3.1</version>
        </dependency>
    </dependencies>

</project>

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: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"
       default-autowire="byName">

    <!--注解扫描配置-->
    <context:component-scan base-package="com"/>

    <!--内部资源视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <!--前缀解析-->
        <property name="prefix" value="/"/>
        <!--后缀解析-->
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--文件上件必备-->
    <bean class="org.springframework.web.multipart.commons.CommonsMultipartResolver" name="multipartResolver">
        <!--1MB = 1024KB 1KB = 1024B 单位字节/B-->
        <property name="maxUploadSize" value="7340032"/><!--7MB-->
        <!--默认编码格式-->
        <property name="defaultEncoding" value="UTF-8"/>
    </bean>

    <!--使 @Controller 注解生效-->
    <mvc:annotation-driven/>

    <!--配置静态文件资源的访问-->
    <!--否则 WEB-INF 下的 css 等资源文件访问不到-->
    <mvc:resources mapping="/**" location="/WEB-INF/"/>

</beans>

web.xml

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<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
         xmlns="http://java.sun.com/xml/ns/j2ee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
    <!--加载springMVC-->
    <servlet>
        <servlet-name>DispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--配置加载的springMVC-servlet.xml 默认为 servlet-name 的值 XXX-servlet.xml-->
        <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>DispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

FileUtil 工具类 创建文件夹

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package com.util;

import java.io.File;

public class FileUtil {
    /**
     * 根据路径创建文件夹
     */
    public static void createDir(String path) {
        File file = new File(path);
        //不存在则创建文件夹以及子文件夹
        if (!file.exists())
            file.mkdirs();
    }
}

MD5Util 工具类 加密

防止中文名图片可以上传不能显示

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package com.util;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * EncoderByMd5
 */
public class MD5Util {
    public static String EncoderByMd5(String str) {
        MessageDigest md5 = null;
        try {
            md5 = MessageDigest.getInstance("MD5");
            // 这句是关键
            md5.update(str.getBytes("UTF-8"));
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        byte b[] = md5.digest();
        int i;
        StringBuffer buf = new StringBuffer();
        for (int offset = 0; offset < b.length; offset++) {
            i = b[offset];
            if (i < 0)
                i += 256;
            if (i < 16)
                buf.append("0");
            buf.append(Integer.toHexString(i));
        }
        System.out.println(buf.toString());
        return buf.toString();
    }

    public static void main(String[] args) {
        System.out.println(MD5Util.EncoderByMd5("Simon"));
    }
}

ImgController servlet层

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package com.controller;

import com.util.FileUtil;
import com.util.MD5Util;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpSession;
import java.io.File;
import java.io.IOException;

@Controller
public class ImgController {
    //文件上传
    @RequestMapping("/uploadImg")
    public String uploadImg(MultipartFile imgFile, HttpSession session, Model model) {
        //获取上传文件的文件名字
        String filename = imgFile.getOriginalFilename();
        System.out.println(filename);
        //文件名去后缀
        String substring = filename.substring(0, filename.lastIndexOf(".jpg"));
        System.out.println(substring);
        //加密加后缀
        String s = new StringBuffer(MD5Util.EncoderByMd5(substring)).append(".jpg").toString();
        //获取保存文件的目录
        String path = session.getServletContext().getRealPath("/WEB-INF/img");
        System.out.println(path);

        //创建目录
        FileUtil.createDir(path);

        //文件保存路径
        File outFile = new File(path, s);

        model.addAttribute("img", s);
        try {
            imgFile.transferTo(outFile);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return "index";
    }
}

index.jsp 页面

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<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<form action="uploadImg" method="post" enctype="multipart/form-data">
    <input type="file" name="imgFile"/>
    <input type="submit" value="上传"/>
</form>
<img src="/img/${img}" height="700">
</body>
</html>

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