thymeleafexamples.gtvg.web.filter.GTVGFilter 源代码：
package thymeleafexamples.gtvg.web.filter;
import java.io.IOException;
import java.io.Writer;
import jakarta.servlet.Filter;
import jakarta.servlet.FilterChain;
import jakarta.servlet.FilterConfig;
import jakarta.servlet.ServletException;
import jakarta.servlet.ServletRequest;
import jakarta.servlet.ServletResponse;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.thymeleaf.ITemplateEngine;
import org.thymeleaf.TemplateEngine;
import org.thymeleaf.templatemode.TemplateMode;
import org.thymeleaf.templateresolver.WebApplicationTemplateResolver;
import org.thymeleaf.web.IWebApplication;
import org.thymeleaf.web.IWebExchange;
import org.thymeleaf.web.IWebRequest;
import org.thymeleaf.web.servlet.JakartaServletWebApplication;
import thymeleafexamples.gtvg.business.entities.User;
import thymeleafexamples.gtvg.web.controller.IGTVGController;
import thymeleafexamples.gtvg.web.mapping.ControllerMappings;
/**
* 过滤器
* @author Administrator
*/
public class GTVGFilter implements Filter {
private ITemplateEngine templateEngine;
private JakartaServletWebApplication application;
public GTVGFilter() {
super();
}
/**
* 添加用户信息到 session
* @param request
*/
private static void addUserToSession(final HttpServletRequest request) {
// Simulate a real user session by adding a user object
request.getSession(true).setAttribute("user",
new User("John", "Apricot", "Antarctica", null));
}
/**
* 初始化
* @param filterConfig
* @throws ServletException
*/
@Override
public void init(final FilterConfig filterConfig) throws ServletException {
this.application =
JakartaServletWebApplication.buildApplication(filterConfig.getServletContext());
this.templateEngine = buildTemplateEngine(this.application);
}
/**
* 过滤器
* @param request
* @param response
* @param chain
* @throws IOException
* @throws ServletException
*/
@Override
public void doFilter(final ServletRequest request, final ServletResponse response,
final FilterChain chain) throws IOException, ServletException {
addUserToSession((HttpServletRequest)request);
if (!process((HttpServletRequest)request, (HttpServletResponse)response)) {
chain.doFilter(request, response);
}
}
@Override
public void destroy() {
// nothing to do
}
/**
* 处理器，根据URL选择合适的处理器
* @param request
* @param response
* @return
* @throws ServletException
*/
private boolean process(final HttpServletRequest request, final HttpServletResponse response)
throws ServletException {
try {
final IWebExchange webExchange = this.application.buildExchange(request, response);
final IWebRequest webRequest = webExchange.getRequest();
// 忽略 css、图片等资源
if (webRequest.getPathWithinApplication().startsWith("/css") ||
webRequest.getPathWithinApplication().startsWith("/images") ||
webRequest.getPathWithinApplication().startsWith("/favicon")) {
return false;
}
// 根据请求URL地址匹配合适的处理器
final IGTVGController controller = ControllerMappings.resolveControllerForRequest(webRequest);
if (controller == null) {
return false;
}
// 设置响应头
response.setContentType("text/html;charset=UTF-8");
response.setHeader("Pragma", "no-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
// 调用处理器
final Writer writer = response.getWriter();
controller.process(webExchange, this.templateEngine, writer);
return true;
} catch (final Exception e) {
try {
response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
} catch (final IOException ignored) {
// Just ignore this
}
throw new ServletException(e);
}
}
/**
* 构建模板引擎
* @param application
* @return
*/
private static ITemplateEngine buildTemplateEngine(final IWebApplication application) {
final WebApplicationTemplateResolver templateResolver = new WebApplicationTemplateResolver(application);
// HTML是默认模式，但为了更好地理解代码，我们将对其进行设置
templateResolver.setTemplateMode(TemplateMode.HTML);
// 这会将 “home” 转换为 “/WEB-INF/Templates/home.html”
templateResolver.setPrefix("/WEB-INF/templates/");
templateResolver.setSuffix(".html");
// 将模板缓存TTL设置为1小时。如果未设置，条目将驻留在缓存中，直到被LRU驱逐
templateResolver.setCacheTTLMs(Long.valueOf(3600000L));
// 默认情况下，缓存设置为 true。如果希望模板在修改时自动更新，请设置为 false。
templateResolver.setCacheable(false);
final TemplateEngine templateEngine = new TemplateEngine();
templateEngine.setTemplateResolver(templateResolver);
return templateEngine;
}
}
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