Java代码操作Redis

• 　在pom.xml中下载redis的依赖

 　　<dependency>
          <groupId>redis.clients</groupId>
          <artifactId>jedis</artifactId>
          <version>2.9.0</version>
     </dependency>

• 　连接数据库　

  //输入你的ip和 端口
       Jedis jedis = new Jedis("192.168.80.128",6379);
          jedis.auth("613613");  //设置的密码
          System.out.println(jedis.ping());

   效果：

• 操作字符串

 jedis.set("ht","墙头马上遥相顾");

　　在客户端中查看

　　

System.out.println( jedis.get("ht"));

　　服务端测试查看

　

• 操作哈希

jedis.hset("user","uname","黄大娘");

edis.hset("user","usex","女");

效果

　　在服务端查看

　　//得到哈希值
        System.out.println(jedis.hgetAll("user"));  //方式一
        System.out.println(jedis.hget("user", "uname"));

• 操作列表

jedis.lpush("shici","青灯","不归客","山有木兮","木有之","墙头","马上");

　　效果

　　

　　服务端测试

 System.out.println(jedis.lpop("shici"));//桟结构，所以是先进后出的道理

　　

•  模拟数据存在redis缓存中

　　HuangSevlet

package com.huang;
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 黄大娘
 * @company dogson有限公司
 * @create  2019-09-18 15:46
 */
@WebServlet("/gethuang")
public class HuangServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //第一次读取数据库，后从缓存中读取数据
        Jedis jedis = new Jedis("192.168.80.128",6379);
        jedis.auth("613613");
        //从缓存中读取用户
        Map cretauser =jedis.hgetAll("cretauser");
        if (cretauser !=null && cretauser.size()>0 ){
            req.setAttribute("msg","从缓存中拿数据");
        }else{
            //第一次登陆获取首页数据
            req.setAttribute("msg","从数据库中拿数据");
            String uname="huangting";
            String upas="123456";
            //把数据库中对应的对象存到缓存中
            jedis.hset("cretauser","uname","huangting");
            jedis.hset("cretauser","upas","123456");
            cretauser = jedis.hgetAll("cretauser");
            req.setAttribute("cretauser",cretauser);
        }
        req.getRequestDispatcher("/index.jsp").forward(req,resp);
    }
}

优化项目

第一次去数据库中拿数据后期在从Redis缓存中拿数据，减少访问数据库的次数提高性能

　　

package com.huangting.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.huangting.blog.dao.BlogDao;
import com.huangting.blog.util.JsonUtils;
import com.huangting.blog.util.LuceneUtil;
import com.huangting.blog.util.PropertiesUtil;
import com.huangting.blog.util.StringUtils;

import freemarker.template.Configuration;
import freemarker.template.Template;
import freemarker.template.TemplateException;

/**
 * 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("192.168.80.128",6379);
            jedis.auth("613613");
            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();
        }
}

运行速度快了蛮多

谢谢观看！