Redis（五）【Java操作redis】

五、Jedis

使用Java操作Redis

什么是Jedis

Jedis 是 Redis 官方推荐的 java 连接开发工具！使用Java操作Redis中间件！如果要使用 java 操作 redis，需要对redis有一定基础

1. 导入对应的依赖

<!--导入jedis包-->
<!-- https://mvnrepository.com/artifact/redis.clients/jedis -->
<dependency>
    <groupId>redis.clients</groupId>
    <artifactId>jedis</artifactId>
    <version>4.2.1</version>
</dependency>
<!--fastjson-->
<!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.80</version>
</dependency>

2. 编码测试

连接数据库 操作命令 断开连接

测试连接

package com.vinjcent;

import redis.clients.jedis.Jedis;

public class TestPing {
          
   
    public static void main(String[] args) {
          
   
        //1、new Jedis 对象即可
        Jedis jedis = new Jedis("127.0.0.1",6379);
        // jedis 所有的方法就是之前所学的所有指令
        System.out.println(jedis.ping());

    }
}

5.1 常用的API

String、List、Set、Hash、Zset

简单的string测试用例

package com.vinjcent;

import redis.clients.jedis.Jedis;

import java.util.Set;

public class TestKey {
          
   

    public static void main(String[] args) {
          
   
    	// 连接redis的ip和端口
        Jedis jedis = new Jedis("127.0.0.1",6379);

        System.out.println("清空数据:   "+ jedis.flushDB());
        System.out.println("判断某个键是否存在:  "+jedis.exists("username"));
        System.out.println("新增<`username`,`vinjcent`>的键值对:  "+jedis.set("username","vinjcent"));
        System.out.println("新增<`password`,`7758258`>的键值对:   "+jedis.set("password","7758258"));
        System.out.println("系统中所有的键如下:  ");
        Set<String> keys = jedis.keys("*");
        System.out.println(keys);
        System.out.println("删除键password:    "+jedis.del("password"));
        System.out.println("判断键password是否存在:    "+jedis.exists("password"));
        System.out.println("查看键username所存储的值的类型:    "+jedis.type("username"));
        System.out.println("随机返回key空间一个:    "+jedis.randomKey());
        System.out.println("重命名key: "+jedis.rename("username","name"));
        System.out.println("取出改后的name:  "+jedis.get("name"));
        System.out.println("按索引查询:  "+jedis.select(0));
        System.out.println("删除当前选择数据库中的所有key:   "+jedis.flushDB());
        System.out.println("返回当前数据库中的key的数目:    "+jedis.dbSize());
        System.out.println("删除所有数据库中的所有key:"+jedis.flushAll());


    }
}

5.2 事务

事务测试用例

package com.vinjcent;

import com.alibaba.fastjson.JSONObject;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.Transaction;

public class TransactionTest {
          
   
    public static void main(String[] args) {
          
   
        Jedis jedis = new Jedis("127.0.0.1",6379);

        jedis.flushDB();

        JSONObject jsonObject = new JSONObject();
        jsonObject.put("hello","world");
        jsonObject.put("name","vinjcent");

        //开启事务
        Transaction multi = jedis.multi();
        String result = jsonObject.toJSONString();
        try {
          
   
            multi.set("user1",result);
            multi.set("user2",result);
            multi.set("user3",result);
            int i = 1/0;            //代码抛出异常,执行失败
            multi.exec();
        } catch (Exception e) {
          
   
            //失败则放弃事务
            multi.discard();
            e.printStackTrace();
        }finally {
          
   
            System.out.println(jedis.get("user1"));
            System.out.println(jedis.get("user2"));
            System.out.println(jedis.get("user3"));

            //关闭连接
            jedis.close();
        }

    }
}