MapDB工具类

参考：http://www.mapdb.org/doc/

package com.gardenplus.gardencase.api.util;

import com.alibaba.fastjson.JSON;
import com.mango.common.utils.basic.StrUtil;
import org.mapdb.DB;
import org.mapdb.DBMaker;
import org.mapdb.Serializer;

import java.lang.reflect.Type;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.TimeUnit;

/**
* mapDB缓存工具类
* @author alen
* @create 2018-01-22 15:10
**/
public class MapDBUtil {

/*
缓存回收策略/基于容量
expireMaxSize：设置缓存的容量，当超出expireMaxSize时，按照LRU进行缓存回收。
缓存回收策略/基于时间
expireAfterCreate/expireAfterUpdate：设置TTL，缓存数据在给定的时间内没有写（创建/覆盖）时，则被回收。即定期的会回收缓存数据。
expireAfterGet：设置TTI， 缓存数据在给定的时间内没有读/写时，则被回收。每次访问时都会更新它的TTI，从而如果该缓存是非常热的数据，则将一直不过期，
可能会导致脏数据存在很长的时间（因此，建议要设置expireAfterCreate/expireAfterUpdate）
SECONDS 秒
MINUTES 分钟
HOURS 小时
*/

private static final ConcurrentMap defaultMap = DBMaker.memoryDB().make()
.hashMap("CaseCache", Serializer.STRING, Serializer.STRING)
.expireMaxSize(10000)
.expireAfterCreate(10, TimeUnit.MINUTES)
.expireAfterUpdate(10, TimeUnit.MINUTES)
.createOrOpen();

private static final DB db = DBMaker.memoryDB().make();


public static void put(String key, Object value, String... strings) {
save(key, value, null, strings);
}

public static void put(String key, Object value, Integer expireTime, String... strings) {
save(key, value, expireTime, strings);
}


/**
* 返回集合
*
* @param key
* @param type
* @param <D>
* @return
*/
public static <D> D get(String key, Type type, String... strings) {

return loadType(key, type, strings);
}


/**
* 返回对象
*
* @param key
* @param D
* @param <D>
* @return
*/
public static <D> D get(String key, Class<D> D, String... strings) {
return load(key, D, strings);
}

public static Object get(String key, String... strings) {
String mapName = null;
if (strings != null && strings.length > 0) {
mapName = strings[0];
}
return load(key, mapName);
}

private static void save(String key, Object value, Integer expireTime, String... strings) {
if (StrUtil.isNotBlank(key) && value != null) {
if (strings != null && strings.length > 0) {
String mapName = strings[0];
ConcurrentMap concurrentMap = null;
if (expireTime != null) {
concurrentMap = db.hashMap(mapName, Serializer.STRING, Serializer.STRING)
.expireMaxSize(10000)
.expireAfterCreate(expireTime, TimeUnit.MINUTES)
.expireAfterUpdate(expireTime, TimeUnit.MINUTES)
.createOrOpen();
} else {
concurrentMap = db.hashMap(mapName, Serializer.STRING, Serializer.STRING).createOrOpen();
}
concurrentMap.put(key, JSON.toJSONString(value));
return;
}
defaultMap.put(key, JSON.toJSONString(value));
}
}

private static Object load(String key, String mapName) {
if (StrUtil.isBlank(key)) {
return null;
}
if (StrUtil.isNotBlank(mapName)) {
ConcurrentMap concurrentMap = db.hashMap(mapName, Serializer.STRING, Serializer.STRING).createOrOpen();
if (concurrentMap != null) {
return concurrentMap.get(key);
}
}
return defaultMap.get(key);
}

private static <D> D load(String key, Class<D> D, String... strings) {
if (StrUtil.isBlank(key) || D == null) {
return null;
}
String keyStr = null;
if (strings != null && strings.length > 0) {
String mapName = strings[0];
ConcurrentMap concurrentMap = db.hashMap(mapName, Serializer.STRING, Serializer.STRING).createOrOpen();
if (concurrentMap != null) {
keyStr = (String) concurrentMap.get(key);
return JSON.parseObject(keyStr, D);
}
}
keyStr = (String) defaultMap.get(key);
if (StrUtil.isBlank(keyStr)) {
return null;
}
return JSON.parseObject(keyStr, D);
}

private static <D> D loadType(String key, Type type, String... strings) {
if (StrUtil.isBlank(key) || type == null) {
return null;
}
String keyStr = null;
if (strings != null && strings.length > 0) {
String mapName = strings[0];
ConcurrentMap concurrentMap = db.hashMap(mapName, Serializer.STRING, Serializer.STRING).createOrOpen();
if (concurrentMap != null) {
keyStr = (String) concurrentMap.get(key);
return JSON.parseObject(keyStr, type);
}
}
keyStr = (String) defaultMap.get(key);
if (StrUtil.isBlank(keyStr)) {
return null;
}
return JSON.parseObject(keyStr, type);
}

public static void main(String[] args) {
// List<GardenSettingBO> list = new ArrayList<>();
// GardenSettingBO gardenSettingBO = new GardenSettingBO();
// gardenSettingBO.setCode("11");
// gardenSettingBO.setId(111);
// gardenSettingBO.setValue("yuuyu");
// list.add(gardenSettingBO);
// MapDBUtil.put("style", 1111);
// MapDBUtil.put("style", list);
// MapDBUtil.put("gardenSettingBO", gardenSettingBO);
// List<GardenSettingBO> list2 = MapDBUtil.get("style", new TypeReference<List<GardenSettingBO>>() {
// }.getType());
// GardenSettingBO gardenSettingBO2 = list2.get(0);
// System.out.println("-----" + gardenSettingBO2.getId());
//
// MapDBUtil.put("style", 1111, "testmap");
// System.out.println("-----" + MapDBUtil.get("style", Integer.TYPE, "testmap"));
// System.out.println("-----" + MapDBUtil.get("style", "testmap"));
}
}


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原文链接：https://blog.csdn.net/u014401141/article/details/79132224