首先，使用redis ，要在pom.xml里添加依赖包：
<dependency>
<groupId>redis.clients</groupId>
<artifactId>jedis</artifactId>
<version>2.9.0</version>
</dependency>
Demo1
Java操作redis，
string（字符串）
hash（哈希）
list（列表）
package com.liuwenwu; import redis.clients.jedis.Jedis; /** * @author LWW * @site www.lww.com * @company * @create 2019-09-18 10:55 * * java代码操作Redis * 连接Redis * 操作字符串 * 操作哈希 * 操作列表list */ public class Demo1 { public static void main(String[] args) { Jedis jedis = new Jedis("192.168.241.132",6379); jedis.auth("123456"); System.out.println(jedis.ping()); // 操作字符串 jedis.set("aaa","张三"); System.out.println(jedis.get("aaa")); // 操作哈希 jedis.hset("user1","uname","李四"); jedis.hset("user1","sex","男"); System.out.println(jedis.hgetAll("user1")); System.out.println(jedis.hget("user1", "uname")); // 操作列表list jedis.lpush("hobby","a","b","c","d","e","f"); System.out.println(jedis.lpop("hobby")); System.out.println(jedis.lpop("hobby")); System.out.println(jedis.rpop("hobby")); } }
模拟将数据对象存入Redis缓存
DemoServlet
package com.liuwenwu; import redis.clients.jedis.Jedis; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.util.Map; /** * @author LWW * @site www.lww.com * @company * @create 2019-09-18 11:15 */ @WebServlet("/getData") public class DemoServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { doPost(req, resp); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // 首页第一次是读取数据库，后面读取缓存（在没有增删改的情况） Jedis jedis = new Jedis("192.168.241.132",6379); jedis.auth("123456"); // 从缓存中获取当前登录的用户信息 Map<String,String> currentUser=jedis.hgetAll("currentUser"); if (currentUser !=null && currentUser.size()>0){ req.setAttribute("msg","从缓存中获取数据"); req.setAttribute("currentUser",currentUser); }else { // 第一次访问首页数据 req.setAttribute("msg","从数据库中获取数据"); String uname = "张三"; String upwd = "123456"; // 接下来把数据库中的对应对象存储到缓存中 jedis.hset("currentUser","uname",uname); jedis.hset("currentUser","upwd",upwd); // 此时能获取到值得原因是上面已经将数据存储到缓存中 currentUser=jedis.hgetAll("currentUser"); req.setAttribute("currentUser",currentUser); } req.getRequestDispatcher("/home.jsp").forward(req,resp); } }
项目实战
将数据库中的数据存入Redis缓存，查询从Redis中获取数据，提高性能
package com.liuwenwu.blog.web; import java.io.File; import java.io.FileWriter; import java.io.IOException; import java.io.Writer; import java.nio.file.Paths; import java.sql.SQLException; import java.util.ArrayList; import java.util.Date; import java.util.HashMap; import java.util.List; import java.util.Map; import javax.servlet.http.HttpServletRequest; import org.apache.lucene.analysis.cn.smart.SmartChineseAnalyzer; import org.apache.lucene.document.Document; import org.apache.lucene.document.Field; import org.apache.lucene.document.StringField; import org.apache.lucene.document.TextField; import org.apache.lucene.index.DirectoryReader; import org.apache.lucene.index.IndexReader; import org.apache.lucene.index.IndexWriter; import org.apache.lucene.index.IndexWriterConfig; import org.apache.lucene.index.Term; import org.apache.lucene.queryparser.classic.QueryParser; import org.apache.lucene.search.IndexSearcher; import org.apache.lucene.search.Query; import org.apache.lucene.search.ScoreDoc; import org.apache.lucene.search.TopDocs; import org.apache.lucene.search.highlight.Formatter; import org.apache.lucene.search.highlight.Highlighter; import org.apache.lucene.search.highlight.QueryScorer; import org.apache.lucene.search.highlight.SimpleHTMLFormatter; import org.apache.lucene.store.Directory; import org.apache.lucene.store.FSDirectory; import org.apache.struts2.ServletActionContext; import org.apache.struts2.dispatcher.Parameter.Request; import com.alibaba.fastjson.JSON; import com.liuwenwu.blog.dao.BlogDao; import com.liuwenwu.blog.util.JsonUtils; import com.liuwenwu.blog.util.LuceneUtil; import com.liuwenwu.blog.util.PropertiesUtil; import com.liuwenwu.blog.util.StringUtils; import freemarker.template.Configuration; import freemarker.template.Template; import freemarker.template.TemplateException; import redis.clients.jedis.Jedis; /** * 专门将网页静态化的类，这里不涉及到lucene * @author Administrator * */ public class FreemarkerBlogAction { private String title; private String bid; private BlogDao blogDao = new BlogDao(); private static Jedis jedis; static { jedis =new Jedis("192.168.241.132",6379); jedis.auth("123456"); jedis.select(0); //选择要操作的数据库 } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public String getBid() { return bid; } public void setBid(String bid) { this.bid = bid; } public String list() { try { HttpServletRequest request = ServletActionContext.getRequest(); if (StringUtils.isBlank(title)) { // 从Redis中获取数据 String bolgListALL =jedis.get("blogList"); if(bolgListALL != null && bolgListALL.length()>0) { System.out.println("使用redis缓存查询"); request.setAttribute("blogList", JSON.parse(bolgListALL)); }else { // 从数据库中查询数据 List<Map<String, Object>> blogList = this.blogDao.freemarker_list(title, null); // 放入缓存 jedis.set("blogList", JSON.toJSONString(blogList)); //传到jsp页面 request.setAttribute("blogList", blogList); System.out.println("从数据中拿数据"); } } else { SmartChineseAnalyzer analyzer = new SmartChineseAnalyzer(); IndexReader indexReader = DirectoryReader .open(FSDirectory.open(Paths.get(PropertiesUtil.getValue("indexPath")))); IndexSearcher searcher = new IndexSearcher(indexReader); // 拿一句话到索引目中的索引文件中的词库进行关键词碰撞 Query query = new QueryParser("title", analyzer).parse(title); TopDocs topDocs = searcher.search(query, 100); // 将碰撞出来的关键词给点亮 QueryScorer queryScorer = new QueryScorer(query); // 以什么形式点亮关键词 Formatter formatter = new SimpleHTMLFormatter("<span style='color:red;'><b>", "</span></b>"); Highlighter highlighter = new Highlighter(formatter, queryScorer); List<Map<String, Object>> blogList = new ArrayList<>(); Map<String, Object> map = null; ScoreDoc[] scoreDocs = topDocs.scoreDocs; for (ScoreDoc scoreDoc : scoreDocs) { map = new HashMap<>(); Document doc = searcher.doc(scoreDoc.doc); map.put("bid", doc.get("bid")); map.put("summary", doc.get("summary")); String titleHighlighter = doc.get("title"); if (StringUtils.isNotBlank(titleHighlighter)) { titleHighlighter = highlighter.getBestFragment(analyzer, "title", titleHighlighter); } map.put("title", titleHighlighter); blogList.add(map); } indexReader.close(); request.setAttribute("blogList", blogList); } } catch (Exception e) { e.printStackTrace(); } return "blogList"; } /** * 这是刷新全局索引调用的方法 * * @return */ public String refreshIndex() { IndexWriterConfig conf = new IndexWriterConfig(new SmartChineseAnalyzer()); Directory d; IndexWriter indexWriter = null; try { // 先将索引库中的索引文件清空 delTempChild(new File(PropertiesUtil.getValue("indexPath"))); d = FSDirectory.open(Paths.get(PropertiesUtil.getValue("indexPath"))); indexWriter = new IndexWriter(d, conf); List<Map<String, Object>> list = blogDao.freemarker_list(null, null); for (Map<String, Object> map : list) { Document doc = new Document(); doc.add(new StringField("id", String.valueOf(map.get("bid")), Field.Store.YES)); doc.add(new StringField("bid", String.valueOf(map.get("bid")), Field.Store.YES)); doc.add(new TextField("title", (String) map.get("title"), Field.Store.YES)); doc.add(new TextField("summary", (String) map.get("summary"), Field.Store.YES)); indexWriter.addDocument(doc); } } catch (IOException e) { e.printStackTrace(); } catch (InstantiationException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } finally { try { if (indexWriter != null) { indexWriter.close(); } } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } return "blogList"; } public void delTempChild(File file) { if (file.isDirectory()) { String[] children = file.list();// 获取文件夹下所有子文件夹 // 递归删除目录中的子目录下 for (int i = 0; i < children.length; i++) { delTempChild(new File(file, children[i])); } } // 目录空了，进行删除 file.delete(); } /** * 修改前期 * * @return */ public String perEidt() { HttpServletRequest request = ServletActionContext.getRequest(); try { Map<String, Object> map = this.blogDao.getBlogById(bid); request.setAttribute("map", map); } catch (InstantiationException | IllegalAccessException | SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return "blogEdit"; } /** * 添加博客 * * @return * @throws SQLException * @throws IllegalAccessException * @throws IllegalArgumentException * @throws SecurityException * @throws NoSuchFieldException */ public String add() { HttpServletRequest request = ServletActionContext.getRequest(); Map parameterMap = request.getParameterMap(); try { // 将博客添加到数据库中 this.blogDao.add(parameterMap); //清除Redis缓存 jedis.del("blogList"); // 获取当前博客的id int maxId = (int) this.blogDao.maxId(); // 添加到lucene 索引库中 addIndex(maxId + "", parameterMap); // 将这篇博客进行网页静态化 addStaticPage(maxId + "", parameterMap); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } return "blogList"; } /** * 这是删除博客的方法 */ public String del() { HttpServletRequest request = ServletActionContext.getRequest(); Map parameterMap = request.getParameterMap(); try { // 数据库中删除博客 this.blogDao.del(request.getParameterMap()); //清除Redis缓存 jedis.del("blogList"); // 删除lucene中对应的文档 IndexWriter indexWriter = getIndexWriter(); indexWriter.deleteDocuments(new Term("id", bid)); indexWriter.forceMergeDeletes(); // 强制删除 indexWriter.commit(); indexWriter.close(); // 删除页面 new File("F:\\java2\\javaxl_lunece_freemarker\\src\\main\\webapp\\freemarker" + bid + ".html").delete(); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } return "blogList"; } /** * 这是修改的方法 * * @return */ public String edit() { HttpServletRequest request = ServletActionContext.getRequest(); Map parameterMap = request.getParameterMap(); try { // 修改数据库中的值 this.blogDao.edit(request.getParameterMap()); //清除Redis缓存 jedis.del("blogList"); // 修改lucene中的文档值 IndexWriter writer = getIndexWriter(); Document doc = new Document(); doc.add(new StringField("id", JsonUtils.getParamVal(parameterMap, "bid"), Field.Store.YES)); doc.add(new StringField("bid", JsonUtils.getParamVal(parameterMap, "bid"), Field.Store.YES)); doc.add(new TextField("title", JsonUtils.getParamVal(parameterMap, "title"), Field.Store.YES)); doc.add(new TextField("summary", JsonUtils.getParamVal(parameterMap, "summary"), Field.Store.YES)); writer.updateDocument(new Term("id", JsonUtils.getParamVal(parameterMap, "bid")), doc); writer.close(); // 修改静态页(相同id会之间覆盖) addStaticPage(JsonUtils.getParamVal(parameterMap, "bid"), parameterMap); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } return "blogList"; } /** * 获取写入对象 * * @return * @throws IOException */ public IndexWriter getIndexWriter() throws IOException { IndexWriterConfig conf = new IndexWriterConfig(new SmartChineseAnalyzer()); Directory d = FSDirectory.open(Paths.get(PropertiesUtil.getValue("indexPath"))); return new IndexWriter(d, conf); } /** * 添加索引文件 * * @param id * @param parameterMap * @throws IOException */ private void addIndex(String id, Map parameterMap) throws IOException { IndexWriter indexWriter = getIndexWriter(); Document doc = new Document(); doc.add(new StringField("id", id, Field.Store.YES)); doc.add(new StringField("bid", id, Field.Store.YES)); doc.add(new TextField("title", JsonUtils.getParamVal(parameterMap, "title"), Field.Store.YES)); doc.add(new TextField("summary", JsonUtils.getParamVal(parameterMap, "summary"), Field.Store.YES)); indexWriter.addDocument(doc); indexWriter.close(); } /** * 这是添加静态页 * * @throws IOException * @throws TemplateException */ public void addStaticPage(String id, Map parameterMap) throws IOException, TemplateException { // 1.创建配置类 Configuration configuration = new Configuration(Configuration.getVersion()); // 2.设置模板所在的目录 configuration.setDirectoryForTemplateLoading( new File("F:\\java2\\javaxl_lunece_freemarker\\src\\main\\webapp\\freemarker")); // 3.设置字符集 configuration.setDefaultEncoding("utf-8"); // 4.加载模板 (这是在 刚刚设置好的 目录下面去找) Template template = configuration.getTemplate("blogDetail.ftl"); Map map = new HashMap<>(); Map<String, Object> blog = new HashMap<>(); blog.put("bid", id); blog.put("title", JsonUtils.getParamVal(parameterMap, "title")); blog.put("releaseDate", new Date()); blog.put("btid", JsonUtils.getParamVal(parameterMap, "btid")); blog.put("clickHit", JsonUtils.getParamVal(parameterMap, "clickHit")); blog.put("content", JsonUtils.getParamVal(parameterMap, "content")); map.put("blog", blog); // // 6.创建Writer对象 Writer out = new FileWriter( new File("F:\\java2\\javaxl_lunece_freemarker\\src\\main\\webapp\\freemarker" +blog.get("bid") + ".html")); // 7.输出 template.process(map, out); // 8.关闭Writer对象 out.close(); } }
测试效果：
从数据库获取数据需要的时间
从Redis中获取数据需要的时间
