package org.douyu.plugins.velocity;
import java.io.File;
import java.io.Writer;
import org.apache.velocity.app.Velocity;
import org.apache.velocity.VelocityContext;
import org.apache.velocity.Template;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.ResourceNotFoundException;
import douyu.mvc.Context;
import douyu.mvc.ViewException;
import douyu.mvc.ViewManager;
/**
*
* @author ZHH
*
*/
public class VelocityViewManager implements ViewManager {
private static final String defaultContentType = "text/html; charset=UTF-8";
private static final String defaultEncoding = "UTF-8";
private Context douyuContext;
private VelocityContext velocityContext = new VelocityContext();
VelocityViewManager(Context douyuContext) {
this.douyuContext = douyuContext;
//如果不加这一行，Velocity会出错:
//java.lang.UnsupportedOperationException: Could not retrieve ServletContext from application attributes
// org.apache.velocity.runtime.log.ServletLogChute.init(ServletLogChute.java:73)
Velocity.setApplicationAttribute("javax.servlet.ServletContext", douyuContext.getServletContext());
Velocity.setProperty(org.apache.velocity.runtime.log.ServletLogChute.RUNTIME_LOG_LEVEL_KEY, "info");
Velocity.setProperty(Velocity.FILE_RESOURCE_LOADER_PATH, douyuContext.getApplicationBase());
Velocity.setProperty(Velocity.FILE_RESOURCE_LOADER_CACHE, true);
if (douyuContext.getHttpServletResponse().getContentType() == null)
douyuContext.getHttpServletResponse().setContentType(defaultContentType);
try {
Velocity.init();
} catch (Exception e) {
throw new ViewException(e);
}
}
private String defaultViewFileName() {
StringBuilder viewFileName = new StringBuilder(50);
viewFileName.append(douyuContext.getControllerClassName().replace('.', File.separatorChar));
viewFileName.append(".");
viewFileName.append(douyuContext.getActionName());
viewFileName.append(".vm");
return viewFileName.toString();
}
@Override
public void out() {
out(defaultViewFileName());
}
@Override
public void out(String viewFileName) {
try {
Template template = Velocity.getTemplate(viewFileName, defaultEncoding);
if (template != null) {
Writer writer = douyuContext.getHttpServletResponse().getWriter();
template.merge(velocityContext, writer);
//writer.flush();
//writer.close();
}
} catch (ResourceNotFoundException rnfe) {
throw new ViewException("Velocity : error : cannot find view file " + viewFileName, rnfe);
} catch (ParseErrorException pee) {
throw new ViewException("Velocity : error : Syntax error in view file " + viewFileName, pee);
} catch (Throwable t) {
throw new ViewException(t);
}
}
@Override
public void put(String key, Object value) {
velocityContext.put(key, value);
}
}