本文實例講述了java實現上傳圖片進行切割的方法。分享給大家供大家參考。具體分析如下：
為什麼我要進行上傳的圖片進行切割呢，我這個項目的圖片是部門logo，每個部門都可以選擇不同的logo，但是要應對瀏覽器的兼容以及拉伸，我選擇了把一張圖片切成左、中、右和剩下的部分，因為左邊和中變可能會有圖案或者字所以不能拉伸，拉伸的只是右邊的部分，剩下的部分自適應就可以了。所以用了javax的ImageReader來操作。最後以blob類型保存數據庫中。
首先要在form表單裡面寫上enctype="multipart/form-data"
複製代碼代碼如下:<form method="post" id="mainForm" action="${ctx }/admin/department!save.action" enctype="multipart/form-data">
下面在表單中寫上上傳組件複製代碼代碼如下:<tr>
<td>
<strong>上傳Logo：</strong>
<input type="hidden" name="suffix" id="suffix" value="${depart.departmentLogo.suffix }"/>
</td>
<td>
<input type="file" name="logoFile" id="logoFile" onchange="checkFile();"/>
</td>
</tr>
<tr>
<td></td>
<td>
<span>（圖片格式：jpg,jpeg,bmp,gif,png;</span><br/>
<span>推薦大小：1120×80像素）</span>
</td>
</tr>
圖片檢查的checkFile()方法用於檢查圖片是否以規定格式結尾以及是否沒有選擇複製代碼代碼如下:function checkFile(){
var value = $("#logoFile").val();
if(!value){
alert("請選擇您要上傳的圖片！");
return false;
}else{
if(value.lastIndexOf(".jpg") != -1){
$("#suffix").val("jpg");
return true;
}else if(value.lastIndexOf(".jpeg") != -1){
$("#suffix").val("jpeg");
return true;
}else if(value.lastIndexOf(".gif") != -1){
$("#suffix").val("gif");
return true;
}else if(value.lastIndexOf(".bmp") != -1){
$("#suffix").val("bmp");
return true;
}else if(value.lastIndexOf(".png") != -1){
$("#suffix").val("png");
return true;
}else{
alert("對不起，您上傳文件格式有誤，請選擇指定格式的圖片文件上傳");
return false;
}
}
}
下面就是進行後台的save操作了。
複製代碼代碼如下:public String save() throws Exception {
HttpServletRequest request = ServletActionContext.getRequest() ;
String departId = request.getParameter("id") ;
String departName = request.getParameter("name") ;
String companyId = request.getParameter("companyId") ;
//圖片後綴
String suffix = request.getParameter("suffix");
List<Menu> listMenu = new ArrayList<Menu>() ;
Company company = new Company() ;
company.setId(Long.valueOf(companyId)) ;
if(this.logoFile != null && departName != null && companyId != null && suffix != null){
//獲取解析圖片的ImageReader
Iterator<ImageReader> imageReaders = ImageIO.getImageReadersByFormatName(suffix);
ImageReader imageReader = imageReaders.next();
//把圖片以字節流的形式傳入
InputStream logoStream = new BufferedInputStream(new FileInputStream(this.logoFile));
//轉為圖片輸入流
ImageInputStream imageInputStream = ImageIO.createImageInputStream(logoStream);
imageReader.setInput(imageInputStream, true);
int imageWidth = imageReader.getWidth(0);
//固定高度80
int imageHeight = 80;
//設置左中右和剩下的寬度
int leftWidth = imageWidth / 2;
int middleWidth = (imageWidth - leftWidth) / 3;
int rightWidth = 5;
int retainWidth = imageWidth - leftWidth -middleWidth - 5;
ImageReadParam readParam = imageReader.getDefaultReadParam();
BufferedImage bImage = null;
//裁剪左半部分
//根據寬和高獲得矩形
Rectangle leftImageRectangle = new Rectangle(0, 0, leftWidth, imageHeight);
readParam.setSourceRegion(leftImageRectangle);
bImage = imageReader.read(0, readParam);
//字節數組輸出流
ByteArrayOutputStream leftByteArrayOutputStream = new ByteArrayOutputStream();
ImageIO.write(bImage, suffix, leftByteArrayOutputStream);
//獲得字節數組
byte[] leftImageData = leftByteArrayOutputStream.toByteArray();
leftByteArrayOutputStream.close();
//Hibernate創建一個blob類型
Blob leftBlob = Hibernate.createBlob(leftImageData, this.departmentManager.getSession());
//裁剪中部部分
Rectangle middleImageRectangle = new Rectangle(leftWidth, 0 , middleWidth, imageHeight);
readParam.setSourceRegion(middleImageRectangle);
bImage = imageReader.read(0, readParam);
ByteArrayOutputStream middleArrayOutputStream = new ByteArrayOutputStream();
ImageIO.write(bImage, suffix, middleArrayOutputStream);
byte[] middleImageData = middleArrayOutputStream.toByteArray();
middleArrayOutputStream.close();
Blob middleBlob = Hibernate.createBlob(middleImageData, this.departmentManager.getSession());
//裁剪右半部分
Rectangle rightImageRectangle = new Rectangle(leftWidth + middleWidth, 0, rightWidth, imageHeight);
readParam.setSourceRegion(rightImageRectangle);
bImage = imageReader.read(0, readParam);
ByteArrayOutputStream rightArrayOutputStream = new ByteArrayOutputStream();
ImageIO.write(bImage, suffix, rightArrayOutputStream);
byte[] rightImageData = rightArrayOutputStream.toByteArray();
rightArrayOutputStream.close();
Blob rightBlob = Hibernate.createBlob(rightImageData, this.departmentManager.getSession());
//保留部分
Rectangle retainRectangle = new Rectangle(leftWidth + middleWidth + rightWidth, 0, retainWidth, imageHeight);
readParam.setSourceRegion(retainRectangle);
bImage = imageReader.read(0, readParam);
ByteArrayOutputStream retainArrayOutputStream = new ByteArrayOutputStream();
ImageIO.write(bImage, suffix, retainArrayOutputStream);
byte[] retainImageData = retainArrayOutputStream.toByteArray();
retainArrayOutputStream.close();
Blob retainBlob = Hibernate.createBlob(retainImageData, this.departmentManager.getSession());
if(!departId.equals("") && departId!=null){
Department d = this.departmentManager.findById(Long.valueOf(departId)) ;
if(this.checkedAuthIds != null){
for(int i=0;i<checkedAuthIds.size();i++){
Menu menu = new Menu() ;
menu.setId(checkedAuthIds.get(i)) ;
listMenu.add(menu) ;
}
d.setMenus(listMenu) ;
}
d.getDepartmentLogo().setLeftPartImage(leftBlob);
d.getDepartmentLogo().setMiddlePartImage(middleBlob);
d.getDepartmentLogo().setRightPartImage(rightBlob);
d.getDepartmentLogo().setRetainPartImage(retainBlob);
d.getDepartmentLogo().setCreateTime(new Date());
d.getDepartmentLogo().setSuffix(suffix);
d.setName(departName) ;
d.setParentId(0L) ;
d.setNodeType(1) ;
d.setGrade(1) ;
d.setCompany(company) ;
this.departmentManager.save(d) ;
}else{
Integer parentNodeType = 0 ;
Department dd = new Department() ;
if(this.checkedAuthIds!=null && this.checkedAuthIds.size() != 0){
for(int i=0;i<checkedAuthIds.size();i++){
Menu menu = new Menu() ;
menu.setId(checkedAuthIds.get(i)) ;
listMenu.add(menu) ;
}
dd.setMenus(listMenu) ;
}else{
dd.setMenus(null) ;
}
DepartmentLogo departmentLogo = new DepartmentLogo() ;
departmentLogo.setCreateTime(new Date());
departmentLogo.setLeftPartImage(leftBlob);
departmentLogo.setMiddlePartImage(middleBlob);
departmentLogo.setRightPartImage(rightBlob);
departmentLogo.setRetainPartImage(retainBlob);
departmentLogo.setSuffix(suffix);
dd.setDepartmentLogo(departmentLogo);
dd.getDepartmentLogo().setDepartment(dd);
dd.setId(this.departmentManager.findMaxId()+1) ;
dd.setName(departName) ;
dd.setParentId(0L) ;
dd.setNodeType(1) ;
dd.setGrade(1) ;
dd.setOrderType(0) ;
dd.setCompany(company) ;
dd.setFlag(0) ;
this.departmentManager.save(dd) ;
}
}
return "reload";
}
下面就是顯示了，我是用的qui，所以在top.jsp上面的css中進行動態顯示複製代碼代碼如下:<style type="text/css">
.welcome-hide{width: 210px;white-space: nowrap;overflow: hidden;text-overflow: ellipsis;}
#leftLogo{background: url(${ctx }/admin/department-logo!showLogo.action?position=left) no-repeat;width: ${leftWidth}px;height: 80px;}
#middleLogo{background: url(${ctx }/admin/department-logo!showLogo.action?position=middle) no-repeat;width: ${middleWidth}px;height: 80px;}
#rightLogo,#topTableStyle{background: url(${ctx }/admin/department-logo!showLogo.action?position=right) repeat-x;height: 80px;}
#retainLogo{background: url(${ctx }/admin/department-logo!showLogo.action?position=retain) no-repeat;width: ${retainWidth}px;height: 80px;}
</style>
department-logo!showLogo.action中的showLogo方法就是加載圖片的方法複製代碼代碼如下:public String showLogo() {
HttpServletRequest request = ServletActionContext.getRequest();
LoginUser loginUser = (LoginUser)((SecurityContext)request.getSession().
getAttribute("SPRING_SECURITY_CONTEXT")).getAuthentication().getPrincipal();
List<DepartmentLogo> logos = this.logoManager.findAll();
for (DepartmentLogo departmentLogo : logos) {
if (loginUser.getUser().getDepartment().getId().equals(departmentLogo.getDepartment().getId())) {
String param = request.getParameter("position");
Blob blob = null;
if (param != null) {
try {
if (param.equals("left")) {
blob = departmentLogo.getLeftPartImage();
imageLogo = blob.getBinaryStream();
return "showLogo";
}else if (param.equals("middle")) {
blob = departmentLogo.getMiddlePartImage();
imageLogo = blob.getBinaryStream();
return "showLogo";
}else if (param.equals("right")) {
blob = departmentLogo.getRightPartImage();
imageLogo = blob.getBinaryStream();
return "showLogo";
}else if (param.equals("retain")) {
blob = departmentLogo.getRetainPartImage();
imageLogo = blob.getBinaryStream();
return "showLogo";
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
return null;
}
當然返回的地址應該選擇struts2中的type="stream"
複製代碼代碼如下:@Results({
@Result(name = "showLogo", type = "stream", params = {"contentType", "image/jpeg,"
+ "image/bmp,image/png,image/gif,image/jpeg",
"inputName", "imageLogo", "bufferSize", "4096"})
})
那麼top.jsp中的width是怎麼得到的呢？
實在加載菜單的時候得到的，下面是menu中的方法複製代碼代碼如下:HttpServletRequest request = ServletActionContext.getRequest();
List<DepartmentLogo> logos = this.logoManager.findAll();
for (DepartmentLogo departmentLogo : logos) {
if (user.getDepartment().getId().equals(departmentLogo.getDepartment().getId())) {
request.setAttribute("leftWidth", ImageIO.read(departmentLogo.
getLeftPartImage().getBinaryStream()).getWidth());
request.setAttribute("middleWidth", ImageIO.read(departmentLogo.
getMiddlePartImage().getBinaryStream()).getWidth());
request.setAttribute("retainWidth", ImageIO.read(departmentLogo.
getRetainPartImage().getBinaryStream()).getWidth());
break;
}
}
這樣就完成了一個上傳顯示功能。
這個就是我上傳的測試圖片。
希望本文所述對大家的Java程序設計有所幫助。