Redis（五）【Java操作redis】

谁践踏了优雅 2024-04-07 11:52 65阅读 0赞

### 五、Jedis ###

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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

<dependency>
        <groupId>redis.clients</groupId>
        <artifactId>jedis</artifactId>
        <version>4.2.1</version>
    </dependency>
    
    
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>fastjson</artifactId>
        <version>1.2.80</version>
    </dependency>

1.  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 ####

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**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();
            }
    
        }
    }