Thymeleaf url重写

Thymeleaf允许在应用程序中配置URL重写过滤器，它通过调用Thymeleaf模板生成的每个URL的Servlet API的javax.servlet.http.HttpServletResponse类中的response.encodeURL()方法来实现。要使用URL重写，需要在Web应用程序中配置一个过滤器，该过滤器将在生成的HTML中重写URL。以下是一个简单的示例，演示如何在Spring Boot应用程序中配置Thymeleaf URL重写过滤器：

1.在pom.xml文件中添加以下依赖项：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>

2.在application.properties文件中添加以下配置：

server.servlet.context-path=/myapp
server.tomcat.url-encoding=UTF-8

3.创建一个名为UrlRewriteFilter的Java类，该类实现了javax.servlet.Filter接口，并在doFilter()方法中调用response.encodeURL()方法：

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class UrlRewriteFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) request;
        HttpServletResponse resp = (HttpServletResponse) response;

        String url = req.getRequestURI().substring(req.getContextPath().length());
        String rewrittenUrl = resp.encodeURL(url);

        chain.doFilter(request, new UrlRewriteResponseWrapper(resp, rewrittenUrl));
    }

    @Override
    public void destroy() {
    }
}

4.创建一个名为UrlRewriteResponseWrapper的Java类，该类扩展了javax.servlet.http.HttpServletResponseWrapper类，并重写了encodeURL()方法：

import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import java.io.IOException;

public class UrlRewriteResponseWrapper extends HttpServletResponseWrapper {

    private String rewrittenUrl;

    public UrlRewriteResponseWrapper(HttpServletResponse response, String rewrittenUrl) {
        super(response);
        this.rewrittenUrl = rewrittenUrl;
    }

    @Override
    public String encodeURL(String url) {
        return rewrittenUrl;
    }

    @Override
    public String encodeRedirectURL(String url) {
        return rewrittenUrl;
    }

    @Override
    public String encodeUrl(String url) {
        return rewrittenUrl;
    }

    @Override
    public String encodeRedirectUrl(String url) {
        return rewrittenUrl;
    }

    @Override
    public void sendRedirect(String location) throws IOException {
        super.sendRedirect(rewrittenUrl);    }
}

5.在Spring Boot应用程序的配置类中注册UrlRewriteFilter过滤器：

import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class AppConfig {

    @Bean
    public FilterRegistrationBean<UrlRewriteFilter> urlRewriteFilter() {
        FilterRegistrationBean<UrlRewriteFilter> registrationBean = new FilterRegistrationBean<>();
        registrationBean.setFilter(new UrlRewriteFilter());
        registrationBean.addUrlPatterns("/*");
        return registrationBean;
    }
}

这样，Thymeleaf URL重写过滤器就配置完成了。在Thymeleaf模板中，可以使用th:href属性来生成URL，如下所示：

<a th:href="@{/hello}">Hello</a>

这将生成一个相对于应用程序上下文路径的URL，例如/myapp/hello。当用户单击链接时，UrlRewriteFilter过滤器将调用response.encodeURL()方法来重写URL，以便在会话ID中包含JSESSIONID参数（如果需要）。