概述
rocksdb是一款本地数据库，目前已经在企业应用中用于报表的流式计算的中间缓存，该数据库主要存储在本地硬盘文件中，读取和存储的速度极快，可节约服务器内存，本文提供的rocksdb工具类，可以创建表以及对于表的对象插入读取等操作，但是rocksdb无法同时创建两个连接，否则会报错，具体未知
```java
/**
* @author ：hzz
* @description：TODO
* @date ：2020/12/14 17:38
*/
@Slf4j
public class RocksdbTableUtil {
private RocksDB rocksDB = null;
//用于操作数据库加key的值
List<ColumnFamilyHandle> columnFamilyHandles = new ArrayList<>();
//用于创建数据库或者删除
List<ColumnFamilyDescriptor> columnFamilyDescriptors = new ArrayList<>();
//用于存放key对应的表操作使用的类
ConcurrentMap<String, ColumnFamilyHandle> columnFamilyHandleMap = new ConcurrentHashMap<>();
public RocksdbTableUtil() {
open();
}
/**
* 重整Map缓存表操作的类
*/
private void reconstitutionMap() {
ConcurrentMap<String, ColumnFamilyHandle> columnFamilyHandleMapTemp = new ConcurrentHashMap<>();
if (columnFamilyDescriptors != null && columnFamilyDescriptors.size() > 0) {
for (int i = 0; i < columnFamilyDescriptors.size(); i++) {
ColumnFamilyHandle columnFamilyHandle = columnFamilyHandles.get(i);
String tablename = new String(columnFamilyDescriptors.get(i).columnFamilyName());
if (!columnFamilyHandleMapTemp.containsKey(tablename)) {
columnFamilyHandleMapTemp.put(tablename, columnFamilyHandle);
}
}
columnFamilyHandleMap = columnFamilyHandleMapTemp;
}
}
public void open() {
try {
String property = System.getProperty("user.dir");
String dbPath = property + File.separator + "rocks";
//dbPath = "D:\test\rocksdb";
// String dbPath = "/ascs/rocks";
Options options = new Options();
options.setCreateIfMissing(true);
List<byte[]> cfs = RocksDB.listColumnFamilies(options, dbPath);
if (cfs.size() > 0) {
for (byte[] cf : cfs) {
columnFamilyDescriptors.add(new ColumnFamilyDescriptor(cf, new ColumnFamilyOptions()));
}
} else {
columnFamilyDescriptors.add(new ColumnFamilyDescriptor(RocksDB.DEFAULT_COLUMN_FAMILY, new ColumnFamilyOptions()));
}
DBOptions dbOptions = new DBOptions();
dbOptions.setCreateIfMissing(true);
rocksDB = RocksDB.open(dbOptions, dbPath, columnFamilyDescriptors, columnFamilyHandles);
reconstitutionMap();
} catch (Exception e) {
log.error("创建rocksdb异常", e);
}
}
/**
* 删除表
*
* @param tableName
*/
public void dropTable(String tableName) {
tableName = tableName.toLowerCase();
Integer integer = isexsitTable(tableName);
if (integer != null) {
try {
rocksDB.dropColumnFamily(columnFamilyHandles.get(integer));
columnFamilyHandles.remove(integer.intValue());
columnFamilyDescriptors.remove(integer.intValue());
columnFamilyHandleMap.remove(tableName);
log.debug("删除rocksdb表名为:" + tableName);
} catch (RocksDBException e) {
log.error("删除rocksdb的表异常,表名:" + tableName, e);
}
} else {
log.error("表不存在无法删除,表名:" + tableName);
}
}
/**
* 创建表
*
* @param tableName
*/
public void createTable(String tableName) {
try {
tableName = tableName.toLowerCase();
Integer integer = isexsitTable(tableName);
if (integer == null) {
ColumnFamilyHandle columnFamilyHandle = rocksDB.createColumnFamily(
new ColumnFamilyDescriptor(tableName.getBytes(), new ColumnFamilyOptions()));
columnFamilyDescriptors.add(new ColumnFamilyDescriptor(tableName.getBytes(), new ColumnFamilyOptions()));
columnFamilyHandles.add(columnFamilyHandle);
columnFamilyHandleMap.put(tableName, columnFamilyHandle);
log.debug("创建rocksdb表名为:" + tableName);
}
} catch (RocksDBException e) {
log.error("创建rocksdb的表异常,表名:" + tableName, e);
}
}
/**
* 判断是否存在该表,并获取该表对应的删除标志
*
* @return
*/
private Integer isexsitTable(String tableName) {
tableName = tableName.toLowerCase();
Integer co = null;
for (int i = 0; i < columnFamilyDescriptors.size(); i++) {
if (new String(columnFamilyDescriptors.get(i).columnFamilyName()).equals(tableName)) {
co = i;
break;
}
}
return co;
}
public void put(String tableName, String key) {
try {
tableName = tableName.toLowerCase();
if (columnFamilyHandleMap.containsKey(tableName)) {
ColumnFamilyHandle columnFamilyHandle = columnFamilyHandleMap.get(tableName);
rocksDB.put(columnFamilyHandle, key.getBytes(), new byte[]{});
} else {
log.debug(tableName + "表不存在,key存储失败" + key);
}
} catch (RocksDBException e) {
log.error("添加rocksDB:key值数据异常", e);
}
}
public void put(String tableName, String key, Object value) {
try {
tableName = tableName.toLowerCase();
if (columnFamilyHandleMap.containsKey(tableName)) {
ColumnFamilyHandle columnFamilyHandle = columnFamilyHandleMap.get(tableName);
rocksDB.put(columnFamilyHandle, key.getBytes(), JSON.toJSONString(value).getBytes());
} else {
log.debug(tableName + "表不存在,key存储失败" + key);
}
} catch (RocksDBException e) {
log.error("添加rocksDB:key值数据异常", e);
}
}
/**
* 是否存在这个key
*
* @param tableName
* @param key
* @return
*/
public boolean isexsitkey(String tableName, String key) {
tableName = tableName.toLowerCase();
boolean arg = false;
try {
if (columnFamilyHandleMap.containsKey(tableName)) {
ColumnFamilyHandle columnFamilyHandle = columnFamilyHandleMap.get(tableName);
byte[] bytes = new byte[0];
bytes = rocksDB.get(columnFamilyHandle, key.getBytes());
if (bytes != null) {
arg = true;
}
}
} catch (RocksDBException e) {
log.error("获取rocksDB:key值数据异常", e);
}
return arg;
}
public <T> T get(String tableName, String key, Class<T> cls) {
tableName = tableName.toLowerCase();
T object = null;
try {
if (columnFamilyHandleMap.containsKey(tableName)) {
ColumnFamilyHandle columnFamilyHandle = columnFamilyHandleMap.get(tableName);
byte[] bytes = new byte[0];
bytes = rocksDB.get(columnFamilyHandle, key.getBytes());
if (bytes != null) {
object = (T) JSON.parseObject(new String(bytes), cls);
}
} else {
log.debug(tableName + "表不存在,key获取失败" + key);
}
} catch (RocksDBException e) {
log.error("获取rocksDB:key值数据异常", e);
}
return object;
}
/**
* 批量获取一张表的所有key的内容
*
* @param tableName
* @param keys
* @param cls
*/
public <T> Map<String, T> multiGet(String tableName, List<String> keys, Class<T> cls) {
tableName = tableName.toLowerCase();
Map<String, T> datas = new HashMap<>();
try {
if (columnFamilyHandleMap.containsKey(tableName)) {
List<byte[]> keysbyte = new ArrayList<byte[]>();
for (String key : keys) {
keysbyte.add(key.getBytes());
}
ColumnFamilyHandle columnFamilyHandle = columnFamilyHandleMap.get(tableName);
List<ColumnFamilyHandle> handleList = new ArrayList<>();
handleList.add(columnFamilyHandle);
Map<byte[], byte[]> map = rocksDB.multiGet(handleList, keysbyte);
for (Map.Entry<byte[], byte[]> entry : map.entrySet()) {
T t = JSON.parseObject(new String(entry.getValue()), cls);
datas.put(new String(entry.getKey()), t);
}
}
} catch (RocksDBException e) {
log.error("获取rocksDB:key值数据异常", e);
}
return datas;
}
/**
* 迭代整个库的key和value
*
* @param tableName
* @param iteratorConsumer
*/
public void ConsumeQuery(String tableName, Consumer<RocksIterator> iteratorConsumer) {
tableName = tableName.toLowerCase();
if (columnFamilyHandleMap.containsKey(tableName)) {
ColumnFamilyHandle columnFamilyHandle = columnFamilyHandleMap.get(tableName);
RocksIterator iter = rocksDB.newIterator(columnFamilyHandle);
iteratorConsumer.accept(iter);
// for (iter.seekToFirst(); iter.isValid(); iter.next()) {
// System.out.println(new String(iter.key()) + ":" + new String(iter.value()));
// }
}
}
public void dropAllTable() {
columnFamilyHandleMap.forEach((p, v) -> {
if (!"default".equalsIgnoreCase(p)) {
dropTable(p);
}
});
}
/**
* 关闭rockDB连接
*/
private void close() {
rocksDB.close();
//用于操作数据库加key的值
columnFamilyHandles = new ArrayList<>();
//用于创建数据库或者删除
columnFamilyDescriptors = new ArrayList<>();
//用于存放key对应的表操作使用的类
columnFamilyHandleMap = new ConcurrentHashMap<>();
}
public void restart() {
close();
open();
}
public static void main(String[] args) throws InterruptedException {
RocksdbTableUtil rocksdbTableUtil = new RocksdbTableUtil();
rocksdbTableUtil.dropAllTable();
}
}
最后
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