java web jsp怎么插图片

JSP中插入的图片就是一个html的img标签，如

<img src="images/hi.png"/>

1. 上传图片到服务器的文件系统中

2. 把图片的地址保存到数据库

3. 读取图片的地址，设置到<img src=".."/>的src属性中

java web开发中，使用文件 *** 作类来上传图片并读取，如下代码：

 * @desc: 图片处理工具

 * @author: bingye

 * @createTime: 2015-3-17 下午04:25:32

 * @version: v1.0

 */

public class ImageUtil {

 

    /**

    * 将图片写到客户端

    * @author: bingye

    * @createTime: 2015-3-17 下午04:36:04

    * @history:

    * @param image

    * @param response void

    */

    public static void writeImage(byte[] image,HttpServletResponse response){

        if(image==null){

            return

        }

        byte[] buffer=new byte[1024]

        InputStream is=null

        OutputStream os=null

        try {

            is=new ByteArrayInputStream(image)

            os=response.getOutputStream()

            while(is.read(buffer)!=-1){

                os.write(buffer)

                os.flush()

            }

        } catch (IOException e) {

            e.printStackTrace()

        } finally{

            try {

                if(is!=null){is.close()}

                if(os!=null){os.close()}

            } catch (IOException e) {

                e.printStackTrace()

            }

        }

    }

     

    /**

    * 获取指定路劲图片

    * @author: bingye

    * @createTime: 2015-3-21 上午10:50:44

    * @param filePath

    * @param response void

    */

    public static void writeImage(String filePath,HttpServletResponse response){

        File imageFile=new File(filePath) 

        if(imageFile!=null && imageFile.exists()){

            byte[] buffer=new byte[1024]

            InputStream is=null

            OutputStream os=null

            try {

                is=new FileInputStream(imageFile)

                os=response.getOutputStream()

                while(is.read(buffer)!=-1){

                    os.write(buffer)

                    os.flush()

                }

            } catch (FileNotFoundException e) {

                e.printStackTrace()

            } catch (IOException e) {

                e.printStackTrace()

            } finally{

                try {

                    if(is!=null){is.close()}

                    if(os!=null){os.close()}

                } catch (IOException e) {

                    e.printStackTrace()

                }

            }

        }

    }

     

    /**

    * 图片上传到文件夹

    * @author: bingye

    * @createTime: 2015-3-20 下午08:07:25

    * @param file

    * @param savePath

    * @return boolean

    */

    public static ResultDto uploadToLocal(CommonsMultipartFile file,String savePath){

        if(file!=null && !file.isEmpty()){

            //获取文件名称

            String fileName=file.getOriginalFilename()

            //获取后缀名

            String suffixName=fileName.substring(fileName.indexOf(".")+1)

            //新名称

            String newFileName=System.currentTimeMillis()+"."+suffixName

            //新文件路劲

            String filePath=savePath+newFileName

            //获取存储文件路径

            File fileDir=new File(savePath)

            if(!fileDir.exists()){

                //如果文件夹没有：新建

                fileDir.mkdirs()

            }

            FileOutputStream fos=null

            try {

                fos=new FileOutputStream(filePath)

                fos.write(file.getBytes())

                fos.flush()

                return ResultUtil.success("UPLOAD_SUCCESS", URLEncoder.encode(newFileName,"utf-8"))

            } catch (Exception e) {

                e.printStackTrace()

                return ResultUtil.fail("UPLOAD_ERROR")

            } finally{

                try {

                    if(fos!=null){

                        fos.close()

                    }

                } catch (IOException e) {

                    e.printStackTrace()

                    return ResultUtil.fail("UPLOAD_ERROR")

                }

            }

        }

        return ResultUtil.fail("UPLOAD_ERROR")

    }

     

     

     

}

我们使用一些已有的组件帮助我们实现这种上传功能。

常用的上传组件：

Apache 的 Commons FileUpload

JavaZoom的UploadBean

jspSmartUpload

以下，以FileUpload为例讲解

1、在jsp端

<form id="form1" name="form1" method="post" action="servlet/fileServlet" enctype="multipart/form-data">

要注意enctype="multipart/form-data"

然后只需要放置一个file控件，并执行submit *** 作即可

<input name="file" type="file" size="20" >

<input type="submit" name="submit" value="提交" >

2、web端

核心代码如下：

public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

request.setCharacterEncoding("UTF-8")

DiskFileItemFactory factory = new DiskFileItemFactory()

ServletFileUpload upload = new ServletFileUpload(factory)

try {

List items = upload.parseRequest(request)

Iterator itr = items.iterator()

while (itr.hasNext()) {

FileItem item = (FileItem) itr.next()

if (item.isFormField()) {

System.out.println("表单参数名:" + item.getFieldName() + "，表单参数值:" + item.getString("UTF-8"))

} else {

if (item.getName() != null &&!item.getName().equals("")) {

System.out.println("上传文件的大小:" + item.getSize())

System.out.println("上传文件的类型:" + item.getContentType())

System.out.println("上传文件的名称:" + item.getName())

File tempFile = new File(item.getName())

File file = new File(sc.getRealPath("/") + savePath, tempFile.getName())

item.write(file)

request.setAttribute("upload.message", "上传文件成功！")

}else{

request.setAttribute("upload.message", "没有选择上传文件！")

}

}

}

}catch(FileUploadException e){

e.printStackTrace()

} catch (Exception e) {

e.printStackTrace()

request.setAttribute("upload.message", "上传文件失败！")

}

request.getRequestDispatcher("/uploadResult.jsp").forward(request, response)

}

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