Image Cropper+java實現截圖工具

　　首先，請移步http://jquery-plugins.net/image-cropper-jquery-image-cropping-plugin下載iamge cropper的有關js文件及css文件，下載demo學會使用；

      java提供后台，頁面圖片展示位置點擊彈出模態框，模態框上file框選擇后圖片立即上傳原圖至服務器並展示在頁面（展示需要弄個代理），頁面進行縮放，選取時，提交x(橫坐標)，y(縱坐標)，fator縮放比例至后台，后台根據這些參數對圖片進行裁剪，裁剪成功后再講圖片關閉彈出模態框，模態框頁面調用父頁面js進行賦值，也就是把截取后的圖片顯示在主頁面上；

提供關鍵代碼：

 模態框選擇完圖片需要展示在截取框的servlet(web.xml中配好)：

/**
* Title: 通用文件下載Servlet
* Description: 通用文件下載Servlet
* Copyright: Copyright (c) 2015
* Company: ZTE
* @author djw
* @version 1.0
*/
public class DownloadImageServlet extends HttpServlet {

private static final long serialVersionUID = 1L;
private static final String LOCAL_CHARSET = "UTF-8";

public DownloadImageServlet() {
super();
}

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

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding(LOCAL_CHARSET);

String filename = request.getParameter("fileName");
String fileType = request.getParameter("fileType");
if (filename == null){
return;
}
else{
filename = new String(filename.getBytes("ISO-8859-1"),LOCAL_CHARSET);
}

// 如果前台沒有傳入文件路徑，則從系統配置文件設置的路徑中取
String filepath = request.getParameter("filePath");
if (filepath == null || filepath.trim().equals("")) {
//filepath = Common.getConfig("upload.uploadFileDirectory");
filepath = "C:/Users/djw/Desktop/";
}
else{
filepath = new String(filepath.getBytes("ISO-8859-1"),LOCAL_CHARSET);
}

// 設置響應頭和下載保存的文件名
String newName = request.getParameter("newName");
String resFileName = "";
if(newName == null)
{
resFileName = new String(filename.getBytes(), "ISO-8859-1");
}else{
resFileName = new String(newName.getBytes(), "ISO-8859-1");
}
if("video".equals(fileType)){
response.setContentType("video/mp4");
}else{
response.setContentType("APPLICATION/OCTET-STREAM;charset=" + LOCAL_CHARSET);
}
response.setHeader("Content-Disposition", "attachment; filename=\"" + resFileName + "\"");

// 打開指定文件的流信息
File f = new File(filepath,filename);

// 寫出流信息

/*
* java.io.FileInputStream fileIn = new java.io.FileInputStream(f);
* ServletOutputStream os = response.getOutputStream(); int i_length =
* fileIn.available(); byte buf_1[] = new byte[i_length]; while
* (i_length > 0) { fileIn.read(buf_1); os.write(buf_1); i_length =
* fileIn.available(); } os.close(); fileIn.close();
*/
response.setContentLength((int) f.length());

int i = 0;
byte[] bt = new byte[8192];
ServletOutputStream sos = null;
FileInputStream fis = null;
try {
fis = new FileInputStream(f);
sos = response.getOutputStream();
while ((i = fis.read(bt)) != -1) {
sos.write(bt, 0, i);
}
} catch (FileNotFoundException ex) {
}
catch (Exception ex){
}
finally {
if (sos != null) {
try {
sos.flush();
sos.close();
} catch (IOException ex) {
}

sos = null;
}
if (fis != null) {

try {
fis.close();
} catch (IOException ex) {
}
}
}
}

頁面展示圖片可以用 項目地址+"DownloadImageServlet?"+圖片名