java操作Redis

1. Java访问redis

1 添加依赖

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

2Java连接redis

      Jedis jedis = new Jedis(ip, port);
      jedis.auth("123456");//权限认证
      jedis.ping();
      jedis.select(0);//切换数据库

3.Java操作redis

      string(字符串)
      hash(哈希)
      list(列表)
      set(集合)
      zset(sorted set:有序集合)
      zadd/zrevrange

注1:不需要记得API的方法,只需要查redis命令

java操作Redis赋值取值案例

package com.qukang;

import redis.clients.jedis.HostAndPort;
import redis.clients.jedis.Jedis;

import java.util.Map;

/**
 * @author 屈康
 * @site www.qk.com
 * @company 不讲理公司
 * @create  2019-10-13 11:43
 *
 * 讲解java代码操作redis
 *  String
 *  hash
 *  list
 */
public class Dome1 {
    public static void main(String[] args) {
        Jedis jedis=new Jedis("192.168.195.128",6379);
        jedis.auth("123456");
        System.out.println(jedis.ping());

        /*
        string
         */
        jedis.set("name","zs");
//        jedis.set("age","22");
//        System.out.println(jedis.get("name"));

        /*
        hash
         */
//        jedis.hset("user1","uname","ls");
//        jedis.hset("user1","pwd","123456");
//        jedis.hset("user1","set","nv");
//        System.out.println(jedis.hget("user1", "uname"));
//        Map<String,String> user1 =jedis.hgetAll("user1");
//        for (Map.Entry<String, String> entry : user1.entrySet()) {
//            System.out.println("key:" + entry.getKey() + "," + "value:" + entry.getValue());
//        }

        /*
        list
         */
//        jedis.lpush("hobby","a","b","c","d","e","f","g");
//        System.out.println(jedis.lpop("hobby"));
//        System.out.println(jedis.rpop("hobby"));
    }
}

通过查询体现Redis在项目中的使用

package com.qukang;

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;

/**
 * @author 屈康
 * @site www.qk.com
 * @company 不讲理公司
 * @create  2019-10-13 12:03
 *
 * redis在项目中使用
 *    查询
 *    增删改
 */
@WebServlet("/list")
public class Servlet 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 {
        Jedis jedis=new Jedis("192.168.195.128",6379);
        jedis.auth("123456");
        String bookList=jedis.get("bookList");
        if(null==bookList || "".equals(bookList)){
//      查询数据库
            String mysqlData="data";
//      讲mysqlData转成json数组串
            jedis.set("bookList",mysqlData);
            bookList=jedis.get("bookList");
            req.setAttribute("mag","走了数据库数据");
            req.setAttribute("booklist",bookList);
            req.getRequestDispatcher("/booklist.jsp").forward(req,resp);
//      转成对象
//      转发页面
        }else{
            req.setAttribute("mag","直接从redis里面拿了数据");
            req.setAttribute("booklist",bookList);
            req.getRequestDispatcher("/booklist.jsp").forward(req,resp);
        }
    }
}

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page isELIgnored="false" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
${mag}:${booklist}

</body>
</html>

第一次访问从数据库里拿值

第二次访问从Redis缓存里拿值

2.项目实战

添加依赖
pom.xml

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.qukang</groupId>
  <artifactId>Redis</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>Redis Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
    <servlet.version>4.0.0</servlet.version>
    <mysql.version>5.1.44</mysql.version>
    <jstl.version>1.2</jstl.version>
    <standard.version>1.1.2</standard.version>
    <tomcat-jsp.version>8.0.47</tomcat-jsp.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>${servlet.version}</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>redis.clients</groupId>
      <artifactId>jedis</artifactId>
      <version>2.9.0</version>
    </dependency>

    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>${mysql.version}</version>
    </dependency>



    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>fastjson</artifactId>
      <version>1.2.28</version>
    </dependency>



    <dependency>
      <groupId>jstl</groupId>
      <artifactId>jstl</artifactId>
      <version>${jstl.version}</version>
    </dependency>
    <dependency>
      <groupId>taglibs</groupId>
      <artifactId>standard</artifactId>
      <version>${standard.version}</version>
    </dependency>
    <dependency>
      <groupId>org.apache.tomcat</groupId>
      <artifactId>tomcat-jsp-api</artifactId>
      <version>${tomcat-jsp.version}</version>
    </dependency>


    <dependency>
      <groupId>dom4j</groupId>
      <artifactId>dom4j</artifactId>
      <version>1.6.1</version>
    </dependency>


    <dependency>
      <groupId>commons-beanutils</groupId>
      <artifactId>commons-beanutils</artifactId>
      <version>1.8.0</version>
    </dependency>

    <dependency>
      <groupId>commons-logging</groupId>
      <artifactId>commons-logging</artifactId>
      <version>1.2</version>
    </dependency>
    <dependency>
      <groupId>jaxen</groupId>
      <artifactId>jaxen</artifactId>
      <version>1.2.0</version>
    </dependency>
  </dependencies>

  <build>
    <finalName>Redis</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

BookAction.java

package com.qukang.web;

import java.sql.SQLException;
import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.alibaba.fastjson.JSON;
import com.qukang.dao.BookDao;
import com.qukang.entity.Book;
import com.qukang.framework.ActionSupport;
import com.qukang.framework.ModelDrivern;
import redis.clients.jedis.Jedis;


public class BookAction extends ActionSupport implements ModelDrivern<Book>{
	private Book book = new Book();
	private BookDao bookDao = new BookDao();
	
	/**
	 * 分页查询
	 * @param req
	 * @param resp
	 * @return
	 */
	public String list(HttpServletRequest req,HttpServletResponse resp) {
		try {
			List<Book> list = this.bookDao.list(book, null);
			Jedis jedis=new Jedis("192.168.195.128",6379);
			jedis.auth("123456");
			String booklist = jedis.get("booklist");
			if(booklist==null || "".equals(booklist)){
				System.out.println("先从mysql数据库拿");
				String mysqldata= JSON.toJSONString(list);
				jedis.set("booklist",mysqldata);
				booklist = jedis.get("booklist");
				req.setAttribute("bookList",list);
			}else{
				System.out.println("直接从redis拿");
				req.setAttribute("bookList", JSON.parse(booklist));
                /*jedis.del("booklist");
                System.out.println("查询方法更新缓存");*/
			}

		} catch (InstantiationException | IllegalAccessException | SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return "list";
	}

	/**
	 * 跳转到增加或者修改页面
	 * @param req
	 * @param resp
	 * @return
	 */
	public String preSave(HttpServletRequest req,HttpServletResponse resp) {
//		bid的类型是int类型,而int类型的默认值是0,如果jsp未传递bid的参数值,那么bid=0
		if(book.getBid() == 0) {
			System.out.println("增加逻辑.....");
		}else {
//			修改数据回显逻辑
			try {
//				查单个
				Book b = this.bookDao.list(book, null).get(0);
				req.setAttribute("book", b);
			} catch (InstantiationException | IllegalAccessException | SQLException e) {
				e.printStackTrace();
			}
		}
//		新增页面与修改页面是同一个jsp
		return "edit";
	}

	/**
	 * 新增
	 * @param req
	 * @param resp
	 * @return
	 */
	public String add(HttpServletRequest req,HttpServletResponse resp) {
		try {
			int code= this.bookDao.add(book);
			if(code>0){
				//			更新缓存
				Jedis jedis=new Jedis("192.168.195.128",6379);
				jedis.auth("123456");
				jedis.del("booklist");
				System.out.println("增加方法已执行");
			}
		} catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException
				| SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
//		新增完了后需要刷新页面
		return "toList";
	}

	/**
	 * 修改
	 * @param req
	 * @param resp
	 * @return
	 */
	public String edit(HttpServletRequest req,HttpServletResponse resp) {
		try {
			int code= this.bookDao.edit(book);
			if(code>0){
				Jedis jedis=new Jedis("192.168.195.128",6379);
				jedis.auth("123456");
				jedis.del("booklist");
				System.out.println("修改方法已执行");
			}
		} catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException
				| SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
//		修改完了后需要刷新页面
		return "toList";
	}

	/**
	 * 删除
	 * @param req
	 * @param resp
	 * @return
	 */
	public String del(HttpServletRequest req,HttpServletResponse resp) {
		try {
			int code= this.bookDao.del(book);
			if(code>0){
				Jedis jedis=new Jedis("192.168.195.128",6379);
				jedis.auth("123456");
				jedis.del("booklist");
				System.out.println("删除方法已执行");
			}
		} catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException
				| SQLException e) {
			e.printStackTrace();
		}
		return "toList";
	}
	
	@Override
	public Book getModel() {
		return book;
	}
}

bookList.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ page isELIgnored="false" %>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@taglib uri="/leiyuanlin" prefix="z" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
	<h2>小说目录</h2>
	<br>

	<form action="${pageContext.request.contextPath}/book.action?methodName=list"
		method="post">
		书名:<input type="text" name="bname"> <input type="submit"
			value="确定">
			<input type="hidden" name="rows" value="15">
	</form>
	<a href="${pageContext.request.contextPath}/book.action?methodName=preSave">增加</a>
	<table border="1" width="100%">
		<tr>
			<td>编号</td>
			<td>名称</td>
			<td>价格</td>
			<td>操作</td>
		</tr>
		<c:forEach items="${bookList }" var="b">
			<tr>
				<td>${b.bid }</td>
				<td>${b.bname }</td>
				<td>${b.price }</td>
				<td>
					<a href="${pageContext.request.contextPath}/book.action?methodName=preSave&&bid=${b.bid}">修改</a>&nbsp;
					<a href="${pageContext.request.contextPath}/book.action?methodName=del&&bid=${b.bid}">删除</a>
				</td>
			</tr>
		</c:forEach>
	</table>
	<%--<z:page pageBean="${pageBean }"></z:page>--%>
</body>
</html>

从数据库拿
在这里插入图片描述
从Redis中拿
在这里插入图片描述
操作进程
在这里插入图片描述

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