常用的UTILS工具類：主鍵隨機數；隨機字符/數工具類；redis緩存工具類

1. 生成主鍵隨機數： 時間+隨機數

public class KeyUtil {


    /**
     * 生成唯一的主鍵
     * 格式: 時間+隨機數
     * @return
     */
    public static synchronized String getKey() {
        Random random = new Random();
        Integer number = random.nextInt(900000) + 100000;//生成6位隨機數

        return System.currentTimeMillis() + String.valueOf(number);
    }
}

2.隨機字符串工具類

  /**
     * 生成隨機字符串
     *
     * @param length
     * @param type   0:只生成數字,1：只生成大寫字母,2:只生成小寫字母,其他/null:混合類型
     * @return
     */
    public static String getStrings(Integer length, Integer type) {
        if (null == length || 0 == length) {
            throw new RuntimeException("length is not null or 0");
        }
        char[] aString = new char[length];
        int i = 0;
        Integer f = type;
        while (i < length) {
            if (null == type) {
                f = (int) (Math.random() * 3);
            }
            if (f == 1) {
                aString[i] = (char) ('A' + Math.random() * 26);
            } else if (f == 2) {
                aString[i] = (char) ('a' + Math.random() * 26);
            } else if (f == 0) {
                aString[i] = (char) ('0' + Math.random() * 10);
            } else {
                type = null;
                continue;
            }
            i++;
        }
        String is = new String(aString);
        return is;
    }

1.SpringBoot結合Redis簡單的運用（此功能只運用於登錄（緩存數據量小的數據），當緩存數據量大時不適用）

注：我一般運用IDEA進行開發。

準備工作：1）需要導入相應的jar包依賴。

<dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

2）yml文件的配置

redis:
    host: 127.0.0.1
    port: 6379
    database: 0 #默認是索引爲的0的數據
    jedis:    
      pool:
        max-active: 2
        max-idle: 20
        min-idle: 1
    password: 123456  #redis設置的密碼

注：該配置配置在spring後面即可。

 

3）上代碼

package com.o2o.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import org.springframework.stereotype.Component;

import java.io.Serializable;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.TimeUnit;

/**
 * redicache 工具類
 *
 */
@Component
@Configuration
@EnableCaching
public class RedisService {
    @Autowired
    private StringRedisTemplate template;
    @SuppressWarnings("rawtypes")
    @Autowired
    private RedisTemplate redisTemplate;
    /**
     * 批量刪除對應的value
     *
     * @param keys
     */
    public void remove(final String... keys) {
        for (String key : keys) {
            remove(key);
        }
    }



    /**
     * 批量刪除key
     *
     * @param pattern
     */
    public void removePattern(final String pattern) {
        Set<Serializable> keys = redisTemplate.keys(pattern);
        if (keys.size() > 0)
            redisTemplate.delete(keys);
    }
    /**
     * 刪除對應的value
     *
     * @param key
     */
    public void remove(final String key) {
        if (exists(key)) {
            redisTemplate.delete(key);
        }
    }
    /**
     * 判斷緩存中是否有對應的value
     *
     * @param key
     * @return
     */
    public boolean exists(final String key) {
        return redisTemplate.hasKey(key);
    }
    /**
     * 讀取緩存
     *
     * @param key
     * @return
     */
    public String get(final String key) {
        Object result = null;
        redisTemplate.setValueSerializer(new StringRedisSerializer());
        ValueOperations<Serializable, Object> operations = redisTemplate.opsForValue();
        result = operations.get(key);
        if(result==null){
            return null;
        }
        return result.toString();
    }
    /**
     * 寫入緩存
     *
     * @param key
     * @param value
     * @return
     */
    public boolean set(final String key, Object value) {
        boolean result = false;
        try {
            ValueOperations<Serializable, Object> operations = redisTemplate.opsForValue();
            operations.set(key, value);
            result = true;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }
    /**
     * 寫入緩存 並設置緩存失效時間
     *
     * @param key
     * @param value
     * @return
     */
    public boolean set(final String key, Object value, Long expireTime) {
        boolean result = false;
        try {
            ValueOperations<Serializable, Object> operations = redisTemplate.opsForValue();
            operations.set(key, value);
            redisTemplate.expire(key, expireTime, TimeUnit.SECONDS);
            result = true;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }

    /**
     * 增減
     * @param key
     * @param num
     * @return
     */
    public Long add(final String key,long num){
        try {
            Long increment = redisTemplate.opsForValue().increment(key, num);
            return increment;
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }
    public  boolean hmset(String key, Map<String, String> value) {
        boolean result = false;
        try {
            redisTemplate.opsForHash().putAll(key, value);
            result = true;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }

    public  Map<String,String> hmget(String key) {
        Map<String,String> result =null;
        try {
            result=  redisTemplate.opsForHash().entries(key);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return result;
    }
    @Autowired(required = false)
    public void setRedisTemplate(RedisTemplate redisTemplate) {
        RedisSerializer stringSerializer = new StringRedisSerializer();
        redisTemplate.setKeySerializer(stringSerializer);
        redisTemplate.setValueSerializer(stringSerializer);
        redisTemplate.setHashKeySerializer(stringSerializer);
        redisTemplate.setHashValueSerializer(stringSerializer);
        this.redisTemplate = redisTemplate;
    }
}

注：在此之前碼友們應當在Linux下或者windows下安裝redis