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java实现上传图片进行切割的方法

2019-12-09 14:43Benjamin_whx JAVA教程

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"

复制代码代码如下:
<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

复制代码代码如下:
<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

复制代码代码如下:
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") != -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。

复制代码代码如下:
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<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

复制代码代码如下:
<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方法就是加载图片的方法

复制代码代码如下:
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;  
}

 

当然返回的地址应该选择struts2中的type="stream"

复制代码代码如下:
@Results({  
    @Result(name = "showLogo", type = "stream", params = {"contentType", "image/jpeg,"  
            + "image/bmp,image/png,image/gif,image/jpeg",   
            "inputName", "imageLogo", "bufferSize", "4096"})  
})

 

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

复制代码代码如下:
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;  
    }  
}

 

这样就完成了一个上传显示功能。

java实现上传图片进行切割的方法

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。

  • Java
  • 上传图片
  • 切割

    • 延伸 · 阅读

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