这篇文章主要介绍了java实现上传图片进行切割的方法,以完整实例形式分析了Java针对上传图片进行切割的技巧,非常具有实用价值,需要的朋友可以参考下
本文实例讲述了java实现上传图片进行切割的方法。分享给大家供大家参考。具体分析如下：
为什么我要进行上传的图片进行切割呢，我这个项目的图片是部门logo，每个部门都可以选择不同的logo，但是要应对浏览器的兼容以及拉伸，我选择了把一张图片切成左、中、右和剩下的部分，因为左边和中变可能会有图案或者字所以不能拉伸，拉伸的只是右边的部分，剩下的部分自适应就可以了。所以用了javax的ImageReader来操作。最后以blob类型保存数据库中。
首先要在form表单里面写上enctype=”multipart/form-data”
代码如下:
下面在表单中写上上传组件
代码如下:
上传Logo：
（图片格式：jpg,jpeg,bmp,gif,png;
推荐大小：1120×80像素）
图片检查的checkFile()方法用于检查图片是否以规定格式结尾以及是否没有选择
代码如下:
function checkFile(){
var value = $(“#logoFile”).val();
if(!value){
alert(“请选择您要上传的图片！”);
return false;
}else{
if(value.lastIndexOf(“.jpg-600”) != -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-600”) != -1){
$(“#suffix”).val(“png”);
return true;
}else{
alert(“对不起，您上传文件格式有误，请选择指定格式的图片文件上传”);
return false;
}
}
}
var value = $(“#logoFile”).val();
if(!value){
alert(“请选择您要上传的图片！”);
return false;
}else{
if(value.lastIndexOf(“.jpg-600”) != -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-600”) != -1){
$(“#suffix”).val(“png”);
return true;
}else{
alert(“对不起，您上传文件格式有误，请选择指定格式的图片文件上传”);
return false;
}
}
}
下面就是进行后台的save操作了。
代码如下:
public String save() throws Exception {
HttpServletRequest request = ServletActionContext.getRequest() ;
String departId = request.getParameter(“id”) ;
String departName = request.getParameter(“name”) ;
String companyId = request.getParameter(“companyId”) ;
//图片后缀
String suffix = request.getParameter(“suffix”);
List
HttpServletRequest request = ServletActionContext.getRequest() ;
String departId = request.getParameter(“id”) ;
String departName = request.getParameter(“name”) ;
String companyId = request.getParameter(“companyId”) ;
//图片后缀
String suffix = request.getParameter(“suffix”);
List
下面就是显示了，我是用的qui，所以在top.jsp上面的css中进行动态显示
代码如下:
.welcome-hide{width: 210px;white-space: nowrap;overflow: hidden;text-overflow: ellipsis;}
#leftLogo{background: url(${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;}
department-logo!showLogo.action中的showLogo方法就是加载图片的方法
代码如下:
public String showLogo() {
HttpServletRequest request = ServletActionContext.getRequest();
LoginUser loginUser = (LoginUser)((SecurityContext)request.getSession().
getAttribute(“SPRING_SECURITY_CONTEXT”)).getAuthentication().getPrincipal();
List 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;
}
HttpServletRequest request = ServletActionContext.getRequest();
LoginUser loginUser = (LoginUser)((SecurityContext)request.getSession().
getAttribute(“SPRING_SECURITY_CONTEXT”)).getAuthentication().getPrincipal();
List 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;
}
当然返回的地址应该选择struts2中的type=”stream”
代码如下:
@Results({
@Result(name = “showLogo”, type = “stream”, params = {“contentType”, “image/jpeg,”
+ “image/bmp,image/png,image/gif,image/jpeg”,
“inputName”, “imageLogo”, “bufferSize”, “4096”})
})
@Result(name = “showLogo”, type = “stream”, params = {“contentType”, “image/jpeg,”
+ “image/bmp,image/png,image/gif,image/jpeg”,
“inputName”, “imageLogo”, “bufferSize”, “4096”})
})
那么top.jsp中的width是怎么得到的呢？
实在加载菜单的时候得到的，下面是menu中的方法
代码如下:
HttpServletRequest request = ServletActionContext.getRequest();
List 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;
}
}
List 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;
}
}
这样就完成了一个上传显示功能。
这个就是我上传的测试图片。
希望本文所述对大家的Java程序设计有所帮助。
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