Tapestry 显示图片

Tapestry中显示Blob图像
本文介绍如何在Tapestry应用中通过自定义服务组件显示数据库中的Blob图像数据。文章详细解释了创建ImageService服务的过程,并展示了如何将该服务与页面组件结合使用来展示图像。
what you&aposre doing is trying to use a @Insert component to insert a blobin your page. It will never work like that since Tapestry will actually tryto display the string representation of your blob (if you callpersonImage.toString() you&aposll get exactly that "oracle.sql.BLOB@1176e8a").You need something a bit more sophisticated. I&aposve done exactly what you&aposretrying to do so I&aposll explain it to you. I won&apost past all my code since it&apossvery application-specific.First you need to create a service that will produce the image contents, socreate a class for that. Something like this:public class ImageService implements IEngineService {   public ILink getLink(boolean isPost, Object parameters) {      Object personId = parameterArray[0];      Map serviceParameters = new HashMap();      serviceParameters.put(ServiceConstants.SERVICE, getName());      serviceParameters.put(ServiceConstants.PARAMETER, new Object[] {personId });      return linkFactory.constructLink(this, isPost, serviceParameters,true);   }    public String getName() {        return "personImage";    }   public void service(IRequestCycle cycle) throws IOException {      // here you have to set the appropriate content type      // I&aposm assuming it&aposs a jpeg image.      ContentType contentType = new ContentType("image/jpeg");      OutputStream outputStream = webResponse.getOutputStream(contentType);      Object[] parameters = linkFactory.extractListenerParameters(cycle);      Integer personId = (Integer) parameters[0];  // you have the ID, so here you do whatever you have to do      // to fetch the person object      Person person = whatever...      // then you have to write the image contents to the output stream.      int length = person.personImage.length();      outputStream.write(person.personImage.getBytes(0,length));      outputStream.close();   }}On the html page you&aposll have to use an img tag with the source being theservice you just created:On the component&aposs java class you&aposll need something like:// This is the hivemind service being injected@InjectObject("service:ImageService")public abstract IEngineService getProductImageService();public String getImageLink() {    Object[] parameters = new Object[1];    // I&aposm assuming there is a "person" variable in page    // with the person object you want to display.    parameters[0] = person.personID;    return getProductImageService().getLink(false,parameters).getAbsoluteURL();    }... next you&aposll also have to tell hivemind about the service in yourhivemodule.xml<service-point id="ImageService" interface="org.apache.tapestry.engine.IEngineService">   <invoke-factory>      <construct class="my.package.ImageService">         <set-object property="linkFactory" value="infrastructure:linkFactory">      </construct>   </invoke-factory></service-point>  <contribution configuration-id="tapestry.services.FactoryServices">   <service name="personImage" object="service:ImageService"></contribution>That&aposs more or less how I did it. I think that&aposs about it, but if I forgotanything I guess the docs can fill in.Denis
【无人机】基于改进粒子群算法的无人机路径规划研究[和遗传算法、粒子群算法进行比较](Matlab代码实现)内容概要:本文围绕基于改进粒子群算法的无人机路径规划展开研究,重点探讨了在复杂环境中利用改进粒子群算法(PSO)实现无人机三维路径规划的方法,并将其与遗传算法(GA)、标准粒子群算法等传统优化算法进行对比分析。研究内容涵盖路径规划的多目标优化、避障策略、航路点约束以及算法收敛性和寻优能力的评估,所有实验均通过Matlab代码实现,提供了完整的仿真验证流程。文章还提到了多种智能优化算法在无人机路径规划中的应用比较,突出了改进PSO在收敛速度和全局寻优方面的优势。; 适合人群:具备一定Matlab编程基础和优化算法知识的研究生、科研人员及从事无人机路径规划、智能优化算法研究的相关技术人员。; 使用场景及目标:①用于无人机在复杂地形或动态环境下的三维路径规划仿真研究;②比较不同智能优化算法(如PSO、GA、蚁群算法、RRT等)在路径规划中的性能差异;③为多目标优化问题提供算法选型和改进思路。; 阅读建议:建议读者结合文中提供的Matlab代码进行实践操作,重点关注算法的参数设置、适应度函数设计及路径约束处理方式,同时可参考文中提到的多种算法对比思路,拓展到其他智能优化算法的研究与改进中。
评论
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值