java-redis緩存jsp頁面

上代碼--原理是在response返回html的時候直接緩存html內容到redis中去

import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import java.io.CharArrayWriter;
import java.io.PrintWriter;

public class ResponseWrapper extends HttpServletResponseWrapper {
    private PrintWriter cachedWriter;
    private CharArrayWriter bufferedWriter;
 
    public ResponseWrapper(HttpServletResponse response) {
        super(response);
        // 這個是咱們保存返回結果的地方
        bufferedWriter = new CharArrayWriter();
        // 這個是包裝PrintWriter的，讓全部結果經過這個PrintWriter寫入到bufferedWriter中
        cachedWriter = new PrintWriter(bufferedWriter);
    }
 
    @Override
    public PrintWriter getWriter() {
        return cachedWriter;
    }
 
    /**
     * 獲取原始的HTML頁面內容。
     *
     * @return
     */
    public String getResult() {
        return bufferedWriter.toString();
    }
}

 

import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.data.redis.core.StringRedisTemplate;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.concurrent.TimeUnit;

public class RedisPageCacheFilter implements Filter {
    private static final Logger log = LoggerFactory.getLogger(RedisPageCacheFilter.class);
 
    private static ApplicationContext ctx;
    private final static String FILTER_URL_PATTERNS = "patterns";
    private static String[] cacheURLs;
    private static int timeOut;

    @Override
    public void init(FilterConfig config) throws ServletException {
        String patterns = config.getInitParameter(FILTER_URL_PATTERNS);
        timeOut= Integer.parseInt(config.getInitParameter("expireTime"));
        cacheURLs = StringUtils.split(patterns, ",");
    }
 
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletResponse resp = (HttpServletResponse) servletResponse;
        HttpServletRequest request = (HttpServletRequest) servletRequest;

        String url = request.getRequestURI();
        boolean flag = false;
        if (cacheURLs != null && cacheURLs.length > 0) {
            for (String cacheURL : cacheURLs) {
                if (url.contains(cacheURL.trim())||url.matches(cacheURL)) {
                    flag = true;
                    break;
                }
            }
        }

        // 若是包含咱們要緩存的url 就緩存該頁面，不然執行正常的頁面轉向
        if (flag) {
            String query = request.getQueryString();
            if (query != null) {
                query = "?" + query;
            }

            final String key="REDISCACHE:"+url+query;
            log.info("當前請求緩存爲:" + url + query);

            // 訪問的是主頁
            // 從緩存中獲得主頁html
            String html = getHtmlFromCache(key);
            if (null == html) {
                // 緩存中沒有
                // 截取生成的html並放入緩存
                log.info("緩存不存在，生成緩存");
                ResponseWrapper wrapper = new ResponseWrapper(resp);
                // ***** 以上代碼在請求被處理以前執行 *****
                filterChain.doFilter(servletRequest, wrapper);
                // ***** 如下代碼在請求被處理後前執行 *****
                // 放入緩存
                html = wrapper.getResult();
                putIntoCache(key,html);
            }

            // 返回響應
            resp.setContentType("text/html; charset=utf-8");
            resp.getWriter().print(html);
        } else {
            filterChain.doFilter(servletRequest, resp);
            return;
        }
    }

    @Override
    public void destroy() {

    }

    private String getHtmlFromCache(String redisKey) {
        return RedisUtil.get(redisKey);
    }
 
    private void putIntoCache(String redisKey,String html) {
        RedisUtil.set(redisKey, html,timeOut*60);
    }
}

 

 使用方式:配置web.xml

    <!-- 頁面緩存配置 redis cache-->
    <filter>
        <filter-name>redisCachingFilter</filter-name>
        <filter-class>xxxxx.xxxxx.xxxx.RedisPageCacheFilter</filter-class>
        <init-param>
            <param-name>suppressStackTrace</param-name>
            <param-value>false</param-value>
        </init-param>
        <init-param>
            <param-name>expireTime</param-name>
            <param-value>1</param-value>
        </init-param>
        <init-param>
            <param-name>patterns</param-name>
            <param-value>\/\d+.do,\/wap\/product\/list\/\d+.jhtm,\/wap\/product\/content\/\d+.action</param-value>
        </init-param>
    </filter>

    <filter-mapping>
        <filter-name>redisCachingFilter</filter-name>
        <url-pattern>*.do</url-pattern>
    </filter-mapping>

    <filter-mapping>
        <filter-name>redisCachingFilter</filter-name>
        <url-pattern>*.action</url-pattern>
    </filter-mapping>