利用imgareaselect辅助后台实现图片上传裁剪

因为项目当中用到图片裁剪，本来可以不用到后台进行裁剪的，但是要兼容万恶的IE浏览器，所以不得不使用后台进行裁剪。

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这次使用到imgareaselect 插件获取需要裁剪区域的坐标，再由后台进行裁剪操作。

但是这里有一个坑就是上传的图片过大，可能会造成裁剪的区域跟插件中显示的不一样，所以得现在后台对云图片进行压缩在裁剪。

/** 
   * 等比例压缩算法： 
   * 算法思想：根据压缩基数和压缩比来压缩原图，生产一张图片效果最接近原图的缩略图 
   * @param srcURL 原图地址 
   * @param deskURL 缩略图地址 
   * @param comBase 压缩基数 
   * @param scale 压缩限制(宽/高)比例 一般用1： 
   * 当scale>=1,缩略图height=comBase,width按原图宽高比例;若scale<1,缩略图width=comBase,height按原图宽高比例 
   * @throws Exception 
   
   */ 
  public static void saveMinPhoto(String srcURL, String deskURL, double comBase, 
      double scale) throws Exception { 
    File srcFile = new java.io.File(srcURL); 
    String ext = srcURL.substring(srcURL.lastIndexOf(".") + 1);  
    Image src = ImageIO.read(srcFile); 
    int srcHeight = src.getHeight(null); 
    int srcWidth = src.getWidth(null); 
    int deskHeight = 0;// 缩略图高 
    int deskWidth = 0;// 缩略图宽 
    double srcScale = (double) srcHeight / srcWidth; 
    /**缩略图宽高算法*/ 
    if ((double) srcHeight > comBase || (double) srcWidth > comBase) { 
      if (srcScale >= scale || 1 / srcScale > scale) { 
        if (srcScale >= scale) { 
          deskHeight = (int) comBase; 
          deskWidth = srcWidth * deskHeight / srcHeight; 
        } else { 
          deskWidth = (int) comBase; 
          deskHeight = srcHeight * deskWidth / srcWidth; 
        } 
      } else { 
        if ((double) srcHeight > comBase) { 
          deskHeight = (int) comBase; 
          deskWidth = srcWidth * deskHeight / srcHeight; 
        } else { 
          deskWidth = (int) comBase; 
          deskHeight = srcHeight * deskWidth / srcWidth; 
        } 
      } 
    } else { 
      deskHeight = srcHeight; 
      deskWidth = srcWidth; 
    } 
    BufferedImage tag = new BufferedImage(deskWidth, deskHeight, BufferedImage.TYPE_3BYTE_BGR); 
    tag.getGraphics().drawImage(src, 0, 0, deskWidth, deskHeight, null); //绘制缩小后的图 
    FileOutputStream deskImage = new FileOutputStream(deskURL); //输出到文件流 
    ImageIO.write(tag, ext, new File(deskURL));  
    deskImage.close(); 
  }

这就是压缩之后在进行裁剪了，好了上完整代码先

js 代码

function preview(img, selection) { 
  if (!selection.width || !selection.height) 
    return; 
   
  var scaleX = 100 / selection.width; 
  var scaleY = 100 / selection.height; 
 
  $('#preview img').css({ 
    width: Math.round(scaleX * 300), 
    height: Math.round(scaleY * 300), 
    marginLeft: -Math.round(scaleX * selection.x1), 
    marginTop: -Math.round(scaleY * selection.y1) 
  }); 
 
  $('#x1').val(selection.x1); 
  $('#y1').val(selection.y1); 
  $('#x2').val(selection.x2); 
  $('#y2').val(selection.y2); 
  $('#w').val(selection.width); 
  $('#h').val(selection.height);   
} 
 
$(function () { 
   
}); 
 
//上传原始图片 
function uplodImage(target) { 
  if(checkImage(target)){ 
    var url = httpUtils.rootPath+'/component/upload.do'; 
    $.ajaxFileUpload({ 
      url: url, //用于文件上传的服务器端请求地址 
      secureuri: false, //是否需要安全协议，一般设置为false 
      fileElementId: 'uplodimage', //文件上传域的ID 
      dataType: 'json', //返回值类型 一般设置为json 
      success: function (data) //服务器成功响应处理函数 
      { 
        var filePath = data.filePath; 
        $('#photo').attr('src',httpUtils.rootPath+'/component/upload.do?action=download&filepath='+filePath); 
        $('#smallImage').attr('src',httpUtils.rootPath+'/component/upload.do?action=download&filepath='+filePath); 
        $('#imgUrl').val(filePath); 
         $('#photo').imgAreaSelect({  
    aspectRatio: '1:1', 
    x1: 50, y1: 50, x2: 241, y2: 241, 
    handles: true, 
    fadeSpeed: 200, 
    onSelectChange: preview 
  }); 
  $('#x1').val("50"); 
  $('#y1').val("50"); 
  $('#x2').val("241"); 
  $('#y2').val("241"); 
  $('#w').val("191"); 
  $('#h').val("191");  
       } 
      }); 
  } 
   
} 
 
//上传裁剪后的图片 
function upold() { 
 
  if($('#imgUrl').val()==''){ 
    layer.alert("请先选择图片在上传"); 
    return false; 
  } 
   
   
  $.ajax({ 
       type: "post", 
       url:httpUtils.rootPath+'/user/setHeadPicture', 
       beforeSend: function(request) { 
        request.setRequestHeader("jmtcp", header);       
      }, 
       async:false, 
       data: { 
        x:$('#x1').val(), 
        y:$('#y1').val(), 
        width: $('#w').val(), 
        imgUrl : $('#imgUrl').val(), 
        heigth: $('#h').val() 
       }, 
       dataType: "json", 
       success: function(data){ 
            if(data.code==1){ 
               
              layer.alert(data.message,function(){ 
                window.location.href = '../user/grzy.html'; 
              }); 
            }else{ 
              layer.alert(data.message); 
            } 
           } 
     }); 
} 
 
function checkImage(target) { 
  var isIE = /msie/i.test(navigator.userAgent) && !window.opera; 
   var fileSize = 0; 
   var filepath = target.value; 
  // 为了避免转义反斜杠出问题，这里将对其进行转换 
    var re = /(\+)/g; 
    var filename = filepath.replace(re, "#"); 
    // 对路径字符串进行剪切截取 
    var one = filename.split("#"); 
    // 获取数组中最后一个，即文件名 
    var two = one[one.length - 1]; 
    // 再对文件名进行截取，以取得后缀名 
    var three = two.split("."); 
    // 获取截取的最后一个字符串，即为后缀名 
    var last = three[three.length - 1]; 
    // 添加需要判断的后缀名类型 
    var tp = "jpg,gif,bmp,JPG,GIF,BMP,png"; 
    // 返回符合条件的后缀名在字符串中的位置 
    var rs = tp.indexOf(last); 
    // 如果返回的结果大于或等于0，说明包含允许上传的文件类型 
    if(rs < 0){ 
      layer.alert('您选择的上传文件不是有效的图片文件'); 
      return false; 
    } 
//  if (isIE && !target.files) {  // IE浏览器 
//    var filePath = target.value; // 获得上传文件的绝对路径 
//    var fileSystem = new ActiveXObject("Scripting.FileSystemObject"); 
//    // GetFile(path) 方法从磁盘获取一个文件并返回。 
//    var file = fileSystem.GetFile(filePath); 
//    fileSize = file.Size;  // 文件大小，单位：b 
//  } 
//  else {  // 非IE浏览器 
//    fileSize = target.files[0].size; 
//  } 
     var img1 = document.getElementById('photo');  
    //img1.dynsrc=target.value;  
    //img1.fileSize：IE ， fileObj.files[0].fileSize：chrome， fileObj.files[0].size：FF  
    var fileSize = img1.fileSize || target.files[0].fileSize || target.files[0].size;   
  var size = fileSize / 1024 / 1024; 
  if (size > 5) { 
    layer.alert("图片不能大于5M"); 
    return false; 
  } 
  return true; 
}

后台代码

public class CutImageUtils { 
  public static SecureRandom rnd = new SecureRandom(); 
   
  public static String cutImage(int x, int y, int width, int height,String srcPath) throws Exception{ 
    String root = ApplicationContext.getProperty("upload_folder"); 
    String imagePath = root+srcPath; 
     FileInputStream is = null;  
     ImageInputStream iis = null;  
     String uploadFolder = null ; 
    String filepath = null ; 
    String serverName = null ; 
    uploadFolder = ApplicationContext.getProperties().getProperty("upload_folder").toString() ; 
    filepath = generateServerFolder() ; 
    serverName = generateServerName(srcPath) ; 
    File file = new File(uploadFolder + filepath);  
    if (!file.exists()) {  
      file.mkdirs(); 
    }  
    
     try { 
      // 读取图片文件  
      saveMinPhoto(imagePath, imagePath, 300, 0.9d); 
       //resetsize(imagePath, imagePath); 
      is = new FileInputStream(imagePath); 
      String ext = srcPath.substring(srcPath.lastIndexOf(".") + 1);  
       Iterator it = ImageIO.getImageReadersByFormatName(ext);  
       ImageReader reader = it.next();  
      // 获取图片流  
       iis = ImageIO.createImageInputStream(is);  
       reader.setInput(iis, true);  
       ImageReadParam param = reader.getDefaultReadParam();  
       /**  
         *  
         * 图片裁剪区域。Rectangle 指定了坐标空间中的一个区域，通过 Rectangle 对象  
         *  
         * 的左上顶点的坐标(x，y)、宽度和高度可以定义这个区域。  
         */  
       Rectangle rect = new Rectangle(x, y, width, height);  
    
        // 提供一个 BufferedImage，将其用作解码像素数据的目标。  
       param.setSourceRegion(rect);  
       BufferedImage bi = reader.read(0, param);  
       // 保存新图片  
       ImageIO.write(bi, ext, new File(uploadFolder + filepath + serverName));  
    } catch (FileNotFoundException e) { 
      // TODO Auto-generated catch block 
      if (is != null)  
        is.close();  
      if (iis != null)  
        iis.close();  
      e.printStackTrace(); 
    }  
     return filepath + serverName ; 
  } 
 
    /** 
   *  
   * @param config 
   * @param file 
   * @param request 
   * @return 
   */ 
  public static String generateServerName(String clientPath) { 
    //按当前时间的分钟毫秒+3位随机数 
    Calendar c = Calendar.getInstance(); 
    String min = get(c,Calendar.MINUTE); 
    String sec = get(c,Calendar.SECOND); 
    String mis = get(c,Calendar.MILLISECOND); 
    String rnd = random(); 
    String ext = getFileExt(getClientName(clientPath)); 
     
    return min + sec + mis + rnd + ext ; 
  } 
   
  /** 客户端文件名 */ 
  public static String getClientName(String clientPath) { 
    if(null != clientPath){ 
      int index1 = clientPath.lastIndexOf("/"); 
      int index2 = clientPath.lastIndexOf("\\"); 
      if(index2 > index1){ 
        index1 = index2; 
      } 
      return clientPath.substring(index1+1,clientPath.length()); 
    } 
    return null; 
  } 
   
  public static String getFileExt(String fileName){ 
    if(null != fileName){ 
      int dot = fileName.lastIndexOf("."); 
      if(dot >= 0){ 
        return fileName.substring(dot); 
      } 
    } 
    return ""; 
  } 
   
  public static String random(){ 
    String value = String.valueOf(rnd.nextInt(1000)); 
    if(value.length() < 3){ 
      for(int i=value.length();i<3;i++){ 
        value = "0" + value; 
      } 
    } 
    return value; 
  } 
   
  public static String generateServerFolder() { 
    //按当前年月日和小时生成文件路径 
    Calendar c = Calendar.getInstance(); 
    String year = get(c,Calendar.YEAR); 
    String mon = get(c,Calendar.MONTH); 
    String day = get(c,Calendar.DAY_OF_MONTH); 
    String hour = get(c,Calendar.HOUR_OF_DAY); 
     
    return year + "/" + mon + "/" + day + "/" + hour + "/"; 
  } 
 
  public static String get(Calendar c,int field){ 
    int v = c.get(field); 
    if(field == Calendar.MONTH){ 
      v += 1; 
    } 
    String value = String.valueOf(v); 
    if(value.length() == 1){ 
      value = "0" + value; 
    } 
    return value; 
  } 
   
  /** 
   * 缩小图片到固定长高 
   * @param srcImagePath 读取图片路径 
   * @param toImagePath 写入图片路径 
   * @param width 缩小后图片宽度 
   * @param height 缩小后图片长度 
   * @throws IOException 
   */ 
  public static void reduceImageByWidthHeight(String srcImagePath, String toImagePath, int width, int height) throws IOException{ 
    FileOutputStream out = null; 
    try{ 
      //读入文件  
      File file = new File(srcImagePath);  
      String ext = srcImagePath.substring(srcImagePath.lastIndexOf(".") + 1);  
      // 构造Image对象  
      BufferedImage src = javax.imageio.ImageIO.read(file);  
      // 缩小边长  
      BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);  
      // 绘制缩小后的图片  
      tag.getGraphics().drawImage(src, 0, 0, width, height, null);  
      out = new FileOutputStream(toImagePath);  
      ImageIO.write(tag, ext, new File(toImagePath));  
    }catch(Exception e){ 
      e.printStackTrace(); 
    }finally{ 
      if(out != null){ 
        out.close();  
      } 
      out = null; 
      System.gc(); 
    } 
  } 
   
  /** 
   * 等比例压缩算法：  
   * 算法思想：根据压缩基数和压缩比来压缩原图，生产一张图片效果最接近原图的缩略图 
   * @param srcURL 原图地址 
   * @param deskURL 缩略图地址 
   * @param comBase 压缩基数 
   * @param scale 压缩限制(宽/高)比例 一般用1： 
   * 当scale>=1,缩略图height=comBase,width按原图宽高比例;若scale<1,缩略图width=comBase,height按原图宽高比例 
   * @throws Exception 
   
   */ 
  public static void saveMinPhoto(String srcURL, String deskURL, double comBase, 
      double scale) throws Exception { 
    File srcFile = new java.io.File(srcURL); 
    String ext = srcURL.substring(srcURL.lastIndexOf(".") + 1);  
    Image src = ImageIO.read(srcFile); 
    int srcHeight = src.getHeight(null); 
    int srcWidth = src.getWidth(null); 
    int deskHeight = 0;// 缩略图高 
    int deskWidth = 0;// 缩略图宽 
    double srcScale = (double) srcHeight / srcWidth; 
    /**缩略图宽高算法*/ 
    if ((double) srcHeight > comBase || (double) srcWidth > comBase) { 
      if (srcScale >= scale || 1 / srcScale > scale) { 
        if (srcScale >= scale) { 
          deskHeight = (int) comBase; 
          deskWidth = srcWidth * deskHeight / srcHeight; 
        } else { 
          deskWidth = (int) comBase; 
          deskHeight = srcHeight * deskWidth / srcWidth; 
        } 
      } else { 
        if ((double) srcHeight > comBase) { 
          deskHeight = (int) comBase; 
          deskWidth = srcWidth * deskHeight / srcHeight; 
        } else { 
          deskWidth = (int) comBase; 
          deskHeight = srcHeight * deskWidth / srcWidth; 
        } 
      } 
    } else { 
      deskHeight = srcHeight; 
      deskWidth = srcWidth; 
    } 
    BufferedImage tag = new BufferedImage(deskWidth, deskHeight, BufferedImage.TYPE_3BYTE_BGR); 
    tag.getGraphics().drawImage(src, 0, 0, deskWidth, deskHeight, null); //绘制缩小后的图 
    FileOutputStream deskImage = new FileOutputStream(deskURL); //输出到文件流 
    ImageIO.write(tag, ext, new File(deskURL));  
    deskImage.close(); 
  } 
   
   
   
  public static void main(String[] args) { 
    try { 
      String src = CutImageUtils.cutImage(11, 12, 100, 100, "2017/01/04/17/6348162d-5b50-4e7d-b414-93140498f8de.jpg"); 
      System.out.println(src); 
    } catch (Exception e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
    } 
  } 
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持创新互联。

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