扩展webx资源装载器之HttpResourceLoader（一）:简单实现

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<webx-version>3.2.4</webx-version>

...

<dependency>

<groupId>com.alibaba.citrus</groupId>

<artifactId>citrus-webx-all</artifactId>

</dependency>

...

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import java.io.IOException;

import java.io.InputStream;

import java.net.HttpURLConnection;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.Set;

import javax.servlet.ServletContext;

import org.apache.commons.lang.StringUtils;

import org.apache.velocity.runtime.RuntimeConstants;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.context.ApplicationContext;

import org.springframework.context.ApplicationListener;

import org.springframework.context.event.ContextRefreshedEvent;

import org.springframework.web.context.ServletContextAware;

import org.springframework.web.context.WebApplicationContext;

import com.alibaba.citrus.service.resource.Resource;

import com.alibaba.citrus.service.resource.ResourceLoader;

import com.alibaba.citrus.service.resource.ResourceLoaderContext;

import com.alibaba.citrus.service.resource.ResourceLoadingOption;

import com.alibaba.citrus.service.resource.ResourceLoadingService;

import com.alibaba.citrus.service.resource.support.InputStreamResource;

import com.alibaba.citrus.service.template.TemplateService;

import com.alibaba.citrus.service.velocity.impl.VelocityEngineImpl;

import com.alibaba.citrus.service.velocity.impl.VelocityRuntimeInstance;

import static org.springframework.web.context.WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE;

/**

*

* @author yankai913@gmail.com

* @date 2016年4月11日

*/

public class HttpResourceLoader implements ResourceLoader, ServletContextAware,

ApplicationListener<ContextRefreshedEvent> {

private static final Logger logger = LoggerFactory.getLogger(HttpResourceLoader.class);

String resourceRemoteHost = "http://localhost:6666";

String vmEncoding = "UTF-8";

String[] additionalPathArr = new String[] { "", "/common" };

ApplicationContext applicationContext;

ServletContext servletContext;

@Override

public void init(ResourceLoadingService resourceLoadingService) {

}

@Override

public Resource getResource(ResourceLoaderContext context, Set<ResourceLoadingOption> options) {

String resourceName = context.getResourceName();

try {

for (String additionalPath : additionalPathArr) {

String remoteFileURL = this.resourceRemoteHost + additionalPath + resourceName;

HttpUtils.HttpResult httpRequest =

HttpUtils.httpGet(remoteFileURL, null, null, vmEncoding, 3000);

if (httpRequest.code == HttpURLConnection.HTTP_OK) {

String htmlText = httpRequest.content;

wrapHtmlContent(resourceName, htmlText);

ByteArrayInputStream bais = new ByteArrayInputStream(htmlText.getBytes(vmEncoding));

InputStreamResource resource = new PrototypeInputStreamResource(bais);

return resource;

} else {

continue;

}

}

throw new IOException("http get template failed! resourceName=" + resourceName);

} catch (Exception e) {

logger.error("http get template failed! resourceName=" + resourceName + e.getMessage(), e);

}

return null;

}

void wrapHtmlContent(String resourceName, String htmlText) {

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

String timestamp = sdf.format(new Date());

String content = "<!-- http get " + resourceName + "\t" + timestamp + " start -->\n";

content = content + htmlText;

content = "\n<!-- http get " + resourceName + "\t" + timestamp + " end -->\n";

}

@Override

public void setServletContext(ServletContext servletContext) {

this.servletContext = servletContext;

}

@Override

public void onApplicationEvent(ContextRefreshedEvent event) {

if (event.getApplicationContext().getParent() == null) {

WebApplicationContext wac =

(WebApplicationContext) servletContext

.getAttribute(ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);

TemplateService ts = (TemplateService) wac.getBean("templateService");

VelocityEngineImpl ve = (VelocityEngineImpl) ts.getTemplateEngine("vm");

VelocityRuntimeInstance vri = (VelocityRuntimeInstance) ve.getRuntimeServices();

vmEncoding = StringUtils.trimToNull((String) vri.getProperty(RuntimeConstants.INPUT_ENCODING));

}

}

// 保证实时数据，不缓存。

static class PrototypeInputStreamResource extends InputStreamResource {

public PrototypeInputStreamResource(InputStream stream) {

super(stream);

}

public long lastModified() {

return System.currentTimeMillis();

}

}

}