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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"
<form method="post" id="mainform" action="${ctx }/admin/department!save.action" enctype="multipart/form-data">
下面在表单中写上上传组件
<tr>
<td style="width: 100px;">
<strong>上传logo：</strong>
<input type="hidden" name="suffix" id="suffix" value="${depart.departmentlogo.suffix }"/>
</td>
<td style="width: 225px;">
<input type="file" name="logofile" id="logofile" onchange="checkfile();"/>
</td>
</tr>
<tr>
<td style="width: 100px;"></td>
<td style="width: 225px;">
<span class="red">（图片格式：jpg,jpeg,bmp,gif,png;</span><br/>
<span class="red">推荐大小：1120×80像素）</span>
</td>
</tr>
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
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") != -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("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。
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<menu> listmenu = new arraylist<menu>() ;
company company = new company() ;
company.setid(long.valueof(companyid)) ;
if(this.logofile != null && departname != null && companyid != null && suffix != null){
//获取解析图片的imagereader
iterator<imagereader> imagereaders = imageio.getimagereadersbyformatname(suffix);
imagereader imagereader = imagereaders.next();
//把图片以字节流的形式传入
inputstream logostream = new bufferedinputstream(new fileinputstream(this.logofile));
//转为图片输入流
imageinputstream imageinputstream = imageio.createimageinputstream(logostream);
imagereader.setinput(imageinputstream, true);
int imagewidth = imagereader.getwidth(0);
//固定高度80
int imageheight = 80;
//设置左中右和剩下的宽度
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
//根据宽和高获得矩形
rectangle leftimagerectangle = new rectangle(0, 0, leftwidth, imageheight);
readparam.setsourceregion(leftimagerectangle);
bimage = imagereader.read(0, readparam);
//字节数组输出流
bytearrayoutputstream leftbytearrayoutputstream = new bytearrayoutputstream();
imageio.write(bimage, suffix, leftbytearrayoutputstream);
//获得字节数组
byte[] leftimagedata = leftbytearrayoutputstream.tobytearray();
leftbytearrayoutputstream.close();
//hibernate创建一个blob类型
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";
}
下面就是显示了，我是用的qui，所以在top.jsp上面的css中进行动态显示
<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方法就是加载图片的方法
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;
}
当然返回的地址应该选择struts2中的type="stream"
@results({
@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
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;
}
}
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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