基礎操作
Demo1
package com.lst;
import redis.clients.jedis.Jedis;
/**
* @create 2019-09-18 13:45
*
* 講解是Java代碼去操作Redis
* 鏈接Redis
* 操作字符串
* 操作哈希
* 操作列表
*/
public class Demo1 {
public static void main(String[] args) {
Jedis jedis = new Jedis("192.168.146.128",6379);
jedis.auth("123456");
// System.out.println(jedis.ping());
// 操作字符串
// jedis.set("aaa","zs");
// System.out.println(jedis.get("aaa"));
// 操作哈希
// jedis.hset("user1","uname","ls");
// jedis.hset("user1","sex","人妖");
// System.out.println(jedis.hgetAll("user1"));
// System.out.println(jedis.hget("user1", "uname"));
// 操作列表
jedis.lpush("hobby","a","b","c","d","e");
System.out.println(jedis.lpop("hobby"));
System.out.println(jedis.lpop("hobby"));
System.out.println(jedis.rpop("hobby"));
}
}
DemoServlet
package com.lst;
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;
/**
* @create 2019-09-18 14:19
*/
@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 {
// 首頁第一次是讀取數據庫，後面讀取緩存（在沒有增刪改的情況）
Jedis jedis = new Jedis("192.168.146.128",6379);
jedis.auth("123456");
// 從緩存中獲取當前登錄的用戶信息
Map<String, String> currentUser = jedis.hgetAll("currentUser");
if(currentUser != null && currentUser.size()>0){
req.setAttribute("msg","從緩存中獲取數據");
req.setAttribute("currentUser",currentUser);
System.out.println("aaa");
}
else{
System.out.println("bbb");
// 第一次登錄，第一次訪問首頁數據
req.setAttribute("msg","從數據庫中獲取數據");
String uname = "tianqi";
String upass = "123456";
// 接下來把數據中的對應對象存儲到緩存中
jedis.hset("currentUser","uname","tianqi");
jedis.hset("currentUser","upass","123456");
// 此時能回去到值原因是上面已經將數據存儲到緩存中
currentUser = jedis.hgetAll("currentUser");
req.setAttribute("currentUser",currentUser);
}
req.getRequestDispatcher("/home.jsp").forward(req,resp);
}
}
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2019/9/18 0018
Time: 14:19
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page isELIgnored="false" %>
<html>
<head>
<title>Title</title>
</head>
<body>
博客首頁
拿去數據的方式：${msg}<br>
拿到的數據：${currentUser}
</body>
</html>
實踐
在lunece和頁面靜態化的基礎上，我們可以進行優化。
當我們第一次登錄的時候，首先要進入數據庫查數據，然後生成緩存文件。如果下一次我們在數據沒有進行增刪改的情況下，我們可以直接調用緩存文件。
當數據發生改變的時候 ，也就是進行了增刪改。我們就要順帶更新緩存，下一次再次訪問首頁要保證redis中數據跟mysql數據是一致
先導入pom依賴
<!-- Redis -->
<dependency>
<groupId>redis.clients</groupId>
<artifactId>jedis</artifactId>
<version>2.9.0</version>
</dependency>
BlogAction
private static String host = "192.168.146.128"; //連接的IP地址
public static Jedis jedis() {
Jedis jedis = new Jedis(host, 6379);
jedis.auth("123456");// 權限認證
jedis.ping();//判斷是否連接成功（成功pong）
jedis.select(2);// 切換數據庫
return jedis;
}
public String list() {
try {
HttpServletRequest request = ServletActionContext.getRequest();
Map<String, String[]> parameterMap = request.getParameterMap();
if (StringUtils.isBlank(title)) {
//連接Redis
Jedis jedis = jedis();
//獲取緩存數據
String blogList = jedis.get("blogList");
String blogzt = jedis.get("blogzt");
if(blogList != null && blogzt == null) {//當Redis中有數據，
//直接從緩存中獲取數據
blogList = jedis.get("blogList");
System.out.println("從緩存中獲取數據");
}
else {//當Redis中沒有數據的時候
//從數據庫中獲取數據出來
List<Map<String, Object>> list = this.blogDao.list(title, null);
//放入Redis中
jedis.set("blogList", JSON.toJSONString(list));
//拿取值
blogList = jedis.get("blogList");
//清除狀態
jedis.del("blogzt");
System.out.println("從數據庫中獲取數據");
}
request.setAttribute("blogList", JSON.parse(blogList));
} else {
Directory directory = LuceneUtil.getDirectory(PropertiesUtil.getValue("indexPath"));
DirectoryReader reader = LuceneUtil.getDirectoryReader(directory);
IndexSearcher searcher = LuceneUtil.getIndexSearcher(reader);
SmartChineseAnalyzer analyzer = new SmartChineseAnalyzer();
// 拿一句話到索引目中的索引文件中的詞庫進行關鍵詞碰撞
Query query = new QueryParser("title", analyzer).parse(title);
Highlighter highlighter = LuceneUtil.getHighlighter(query, "title");
TopDocs topDocs = searcher.search(query, 100);
// 處理得分命中的文檔
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("id", doc.get("id"));
String titleHighlighter = doc.get("title");
if (StringUtils.isNotBlank(titleHighlighter)) {
titleHighlighter = highlighter.getBestFragment(analyzer, "title", titleHighlighter);
}
map.put("title", titleHighlighter);
map.put("url", doc.get("url"));
blogList.add(map);
}
request.setAttribute("blogList", blogList);
}
} catch (Exception e) {
e.printStackTrace();
}
return "blogList";
}
public String add() throws InstantiationException, IllegalAccessException, NoSuchFieldException, SecurityException,
IllegalArgumentException, SQLException {
HttpServletRequest req = ServletActionContext.getRequest();
Map<String, String[]> paMap = req.getParameterMap();
System.out.println(title + "tit");
int save = blogDao.save(paMap);
// 數據增加成功，同時增加索引
if (save > 0) {
//連接Redis
Jedis jedis = jedis();
//改變state狀態
jedis.set("blogzt", "1");
System.out.println("增加成功");
// 新增索引
IndexWriterConfig conf = new IndexWriterConfig(new SmartChineseAnalyzer());
Directory d;
IndexWriter indexWriter = null;
try {
d = FSDirectory.open(Paths.get(PropertiesUtil.getValue("indexPath")));
indexWriter = new IndexWriter(d, conf);
Document doc = new Document();
doc.add(new StringField("id", id, Field.Store.YES));
doc.add(new TextField("title", title, Field.Store.YES));
doc.add(new TextField("content", content, Field.Store.YES));
doc.add(new StringField("url", url, Field.Store.YES));
indexWriter.addDocument(doc);
System.out.println("添加索引成功");
// 新增靜態頁面
} catch (Exception e) {
e.printStackTrace();
}
return "blogList";
} else {
System.out.println("增加失敗");
return "blogList";
}
}
/**
*
* 刪除指定索引庫中 指定域(fieldName) 包含指定字符串(text) 的索引
*
* @return
* @throws IOException
* @throws InstantiationException
* @throws IllegalAccessException
* @throws NoSuchFieldException
* @throws SecurityException
* @throws IllegalArgumentException
* @throws SQLException
*/
public String del() throws IOException, InstantiationException, IllegalAccessException, NoSuchFieldException,
SecurityException, IllegalArgumentException, SQLException {
HttpServletRequest req = ServletActionContext.getRequest();
int del = blogDao.del(req.getParameterMap());
if (del > 0) {
//連接Redis
Jedis jedis = jedis();
//改變state狀態
jedis.set("blogzt", "1");
System.out.println("刪除成功");
IndexWriterConfig conf = new IndexWriterConfig(new SmartChineseAnalyzer());
Directory d = FSDirectory.open(Paths.get(PropertiesUtil.getValue("indexPath")));
IndexWriter indexWriter = new IndexWriter(d, conf);
// Term：表示詞元，第一個參數:域名, 第二個參數:要刪除含有此關鍵詞的數據
// deleteDocuments(Term... terms)：可以同時根據多個詞元進行刪除
Term term1 = new Term("id", id);
Term term2 = new Term("title", title);
Term term3 = new Term("content", content);
Term term4 = new Term("url", url);
indexWriter.deleteDocuments(term1, term2, term3, term4);
System.out.println("刪除索引成功");
return "blogList";
} else {
System.out.println("刪除失敗");
return "blogList";
}
}
第一次是從數據庫中取出數據
第二次是從緩存中獲取數據
對數據進行增刪改後，第一次是從數據庫獲取的數據
over。。。