rocksdb 是一個(gè)可嵌入的，持久性的 key-value存儲(chǔ)。
以下介紹來(lái)自rocksdb 中文官網(wǎng)
https://rocksdb.org.cn/
它有以下四個(gè)特點(diǎn)
1 高性能：rocksdb使用一套日志結(jié)構(gòu)的數(shù)據(jù)庫(kù)引擎，為了更好的性能，這套引擎是用c++編寫的。 key和value是任意大小的字節(jié)流。
2 為快速存儲(chǔ)而優(yōu)化：rocksdb為快速而又低延遲的存儲(chǔ)設(shè)備（例如閃存或者高速硬盤）而特殊優(yōu)化處理。 rocksdb將最大限度的發(fā)揮閃存和ram的高度率讀寫性能。
3 可適配性 ：rocksdb適合于多種不同工作量類型。 從像myrocks這樣的數(shù)據(jù)存儲(chǔ)引擎， 到應(yīng)用數(shù)據(jù)緩存, 甚至是一些嵌入式工作量，rocksdb都可以從容面對(duì)這些不同的數(shù)據(jù)工作量需求。
4 基礎(chǔ)和高級(jí)的數(shù)據(jù)庫(kù)操作 rocksdb提供了一些基礎(chǔ)的操作，例如打開(kāi)和關(guān)閉數(shù)據(jù)庫(kù)。 對(duì)于合并和壓縮過(guò)濾等高級(jí)操作，也提供了讀寫支持。
??????rockdb 安裝與使用
rocksdb 安裝有多種方式。由于官方?jīng)]有提供對(duì)應(yīng)平臺(tái)的二進(jìn)制庫(kù)，所以需要自己編譯使用。
rocksdb 的安裝很簡(jiǎn)單，但是需要轉(zhuǎn)變一下對(duì)于rocksdb 的看法。它不是一個(gè)重量級(jí)別的數(shù)據(jù)庫(kù)，是一個(gè)嵌入式的key-value 存儲(chǔ)。這意味著你只要在你的maven項(xiàng)目中添加 rocksdb的依賴，就可以在開(kāi)發(fā)環(huán)境中自我嘗試了。如果你沒(méi)有理解這點(diǎn)，你就可能會(huì)走入下面這兩種不推薦的安裝方式。
方式 一 去查看rocksdb 的官網(wǎng) 發(fā)現(xiàn)要寫 一個(gè)c++ 程序（不推薦）
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#include <assert>#include "rocksdb/db.h"rocksdb::db* db;rocksdb::options options;options.create_if_missing = true;rocksdb::status status = rocksdb::db::open(options, "/tmp/testdb", &db);assert(status.ok()); |
創(chuàng)建一個(gè)數(shù)據(jù)庫(kù)？？？？ 怎么和之前用的mysql 或者mongo 不一樣，為啥沒(méi)有一個(gè)start.sh 或者start.bat 之類的腳本。難道要我寫。寫完了編譯發(fā)現(xiàn)還不知道怎么和rocksdb 庫(kù)進(jìn)行關(guān)聯(lián)，怎么辦，我c++都忘完了。
方式二 使用pyrocksdb （不推薦）
http://pyrocksdb.readthedocs.io/en/latest/installation.html
詳細(xì)的安裝文檔見(jiàn)pyrocksdb 的官網(wǎng)安裝文檔。
以上兩種方式對(duì)于熟悉c++ 或者python 的開(kāi)發(fā)者來(lái)說(shuō)都比較友好，但對(duì)于java 開(kāi)發(fā)者來(lái)說(shuō)不是太友好。
接下來(lái)就介紹第三種方式。
方式三 使用maven （推薦）
新建maven 項(xiàng)目，修改pom.xml 依賴?yán)锩嫣砑?/p>
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<dependency> <groupid>org.rocksdb</groupid> <artifactid>rocksdbjni</artifactid> <version>5.8.6</version></dependency> |
可以選擇你喜歡的版本。
然后更高maven 的語(yǔ)言級(jí)別，我這里全局設(shè)置為了1.8
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<profiles> <profile> <id>jdk18</id> <activation> <activebydefault>true</activebydefault> <jdk>1.8</jdk> </activation> <properties> <maven.compiler.source>1.8</maven.compiler.source> <maven.compiler.target>1.8</maven.compiler.target> <maven.compiler.compilerversion>1.8</maven.compiler.compilerversion> </properties> </profile></profiles> |
到這里，環(huán)境就裝好了，是不是又回到了熟悉的java 世界。
然后copy 源碼包下的一個(gè)類，在ide中修改一下運(yùn)行配置，加一個(gè)程序運(yùn)行中數(shù)據(jù)庫(kù)存儲(chǔ)路徑，就可以運(yùn)行測(cè)試了 。我會(huì)在文章最后給出這個(gè)類。
運(yùn)行控制臺(tái)會(huì)有日志輸出，同時(shí)也文件中也會(huì)出現(xiàn)一下新的文件。
后面會(huì)更新更多關(guān)于rockdb 開(kāi)發(fā)api 的介紹，以及在生產(chǎn)中的應(yīng)用，希望大家關(guān)注。
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// copyright (c) 2011-present, facebook, inc. all rights reserved.// this source code is licensed under both the gplv2 (found in the// copying file in the root directory) and apache 2.0 license// (found in the license.apache file in the root directory).import org.rocksdb.*;import org.rocksdb.util.sizeunit;import java.util.arraylist;import java.util.arrays;import java.util.list;import java.util.map;public class rocksdbsample { static { rocksdb.loadlibrary(); } public static void main(final string[] args) { if (args.length < 1) { system.out.println("usage: rocksdbsample db_path"); system.exit(-1); } final string db_path = args[0]; final string db_path_not_found = db_path + "_not_found"; system.out.println("rocksdbsample"); try (final options options = new options(); final filter bloomfilter = new bloomfilter(10); final readoptions readoptions = new readoptions() .setfillcache(false); final statistics stats = new statistics(); final ratelimiter ratelimiter = new ratelimiter(10000000,10000, 10)) { try (final rocksdb db = rocksdb.open(options, db_path_not_found)) { assert (false); } catch (final rocksdbexception e) { system.out.format("caught the expected exception -- %s\n", e); } try { options.setcreateifmissing(true) .setstatistics(stats) .setwritebuffersize(8 * sizeunit.kb) .setmaxwritebuffernumber(3) .setmaxbackgroundcompactions(10) .setcompressiontype(compressiontype.snappy_compression) .setcompactionstyle(compactionstyle.universal); } catch (final illegalargumentexception e) { assert (false); } assert (options.createifmissing() == true); assert (options.writebuffersize() == 8 * sizeunit.kb); assert (options.maxwritebuffernumber() == 3); assert (options.maxbackgroundcompactions() == 10); assert (options.compressiontype() == compressiontype.snappy_compression); assert (options.compactionstyle() == compactionstyle.universal); assert (options.memtablefactoryname().equals("skiplistfactory")); options.setmemtableconfig( new hashskiplistmemtableconfig() .setheight(4) .setbranchingfactor(4) .setbucketcount(2000000)); assert (options.memtablefactoryname().equals("hashskiplistrepfactory")); options.setmemtableconfig( new hashlinkedlistmemtableconfig() .setbucketcount(100000)); assert (options.memtablefactoryname().equals("hashlinkedlistrepfactory")); options.setmemtableconfig( new vectormemtableconfig().setreservedsize(10000)); assert (options.memtablefactoryname().equals("vectorrepfactory")); options.setmemtableconfig(new skiplistmemtableconfig()); assert (options.memtablefactoryname().equals("skiplistfactory")); options.settableformatconfig(new plaintableconfig()); // plain-table requires mmap read options.setallowmmapreads(true); assert (options.tablefactoryname().equals("plaintable")); options.setratelimiter(ratelimiter); final blockbasedtableconfig table_options = new blockbasedtableconfig(); table_options.setblockcachesize(64 * sizeunit.kb) .setfilter(bloomfilter) .setcachenumshardbits(6) .setblocksizedeviation(5) .setblockrestartinterval(10) .setcacheindexandfilterblocks(true) .sethashindexallowcollision(false) .setblockcachecompressedsize(64 * sizeunit.kb) .setblockcachecompressednumshardbits(10); assert (table_options.blockcachesize() == 64 * sizeunit.kb); assert (table_options.cachenumshardbits() == 6); assert (table_options.blocksizedeviation() == 5); assert (table_options.blockrestartinterval() == 10); assert (table_options.cacheindexandfilterblocks() == true); assert (table_options.hashindexallowcollision() == false); assert (table_options.blockcachecompressedsize() == 64 * sizeunit.kb); assert (table_options.blockcachecompressednumshardbits() == 10); options.settableformatconfig(table_options); assert (options.tablefactoryname().equals("blockbasedtable")); try (final rocksdb db = rocksdb.open(options, db_path)) { db.put("hello".getbytes(), "world".getbytes()); final byte[] value = db.get("hello".getbytes()); assert ("world".equals(new string(value))); final string str = db.getproperty("rocksdb.stats"); assert (str != null && !str.equals("")); } catch (final rocksdbexception e) { system.out.format("[error] caught the unexpected exception -- %s\n", e); assert (false); } try (final rocksdb db = rocksdb.open(options, db_path)) { db.put("hello".getbytes(), "world".getbytes()); byte[] value = db.get("hello".getbytes()); system.out.format("get('hello') = %s\n", new string(value)); for (int i = 1; i <= 9; ++i) { for (int j = 1; j <= 9; ++j) { db.put(string.format("%dx%d", i, j).getbytes(), string.format("%d", i * j).getbytes()); } } for (int i = 1; i <= 9; ++i) { for (int j = 1; j <= 9; ++j) { system.out.format("%s ", new string(db.get( string.format("%dx%d", i, j).getbytes()))); } system.out.println(""); } // write batch test try (final writeoptions writeopt = new writeoptions()) { for (int i = 10; i <= 19; ++i) { try (final writebatch batch = new writebatch()) { for (int j = 10; j <= 19; ++j) { batch.put(string.format("%dx%d", i, j).getbytes(), string.format("%d", i * j).getbytes()); } db.write(writeopt, batch); } } } for (int i = 10; i <= 19; ++i) { for (int j = 10; j <= 19; ++j) { assert (new string( db.get(string.format("%dx%d", i, j).getbytes())).equals( string.format("%d", i * j))); system.out.format("%s ", new string(db.get( string.format("%dx%d", i, j).getbytes()))); } system.out.println(""); } value = db.get("1x1".getbytes()); assert (value != null); value = db.get("world".getbytes()); assert (value == null); value = db.get(readoptions, "world".getbytes()); assert (value == null); final byte[] testkey = "asdf".getbytes(); final byte[] testvalue = "asdfghjkl;'?><mnbvcxzqwertyuiop{+_)(*&^%$#@".getbytes(); db.put(testkey, testvalue); byte[] testresult = db.get(testkey); assert (testresult != null); assert (arrays.equals(testvalue, testresult)); assert (new string(testvalue).equals(new string(testresult))); testresult = db.get(readoptions, testkey); assert (testresult != null); assert (arrays.equals(testvalue, testresult)); assert (new string(testvalue).equals(new string(testresult))); final byte[] insufficientarray = new byte[10]; final byte[] enougharray = new byte[50]; int len; len = db.get(testkey, insufficientarray); assert (len > insufficientarray.length); len = db.get("asdfjkl;".getbytes(), enougharray); assert (len == rocksdb.not_found); len = db.get(testkey, enougharray); assert (len == testvalue.length); len = db.get(readoptions, testkey, insufficientarray); assert (len > insufficientarray.length); len = db.get(readoptions, "asdfjkl;".getbytes(), enougharray); assert (len == rocksdb.not_found); len = db.get(readoptions, testkey, enougharray); assert (len == testvalue.length); db.remove(testkey); len = db.get(testkey, enougharray); assert (len == rocksdb.not_found); // repeat the test with writeoptions try (final writeoptions writeopts = new writeoptions()) { writeopts.setsync(true); writeopts.setdisablewal(true); db.put(writeopts, testkey, testvalue); len = db.get(testkey, enougharray); assert (len == testvalue.length); assert (new string(testvalue).equals( new string(enougharray, 0, len))); } try { for (final tickertype statstype : tickertype.values()) { if (statstype != tickertype.ticker_enum_max) { stats.gettickercount(statstype); } } system.out.println("gettickercount() passed."); } catch (final exception e) { system.out.println("failed in call to gettickercount()"); assert (false); //should never reach here. } try { for (final histogramtype histogramtype : histogramtype.values()) { if (histogramtype != histogramtype.histogram_enum_max) { histogramdata data = stats.gethistogramdata(histogramtype); } } system.out.println("gethistogramdata() passed."); } catch (final exception e) { system.out.println("failed in call to gethistogramdata()"); assert (false); //should never reach here. } try (final rocksiterator iterator = db.newiterator()) { boolean seektofirstpassed = false; for (iterator.seektofirst(); iterator.isvalid(); iterator.next()) { iterator.status(); assert (iterator.key() != null); assert (iterator.value() != null); seektofirstpassed = true; } if (seektofirstpassed) { system.out.println("iterator seektofirst tests passed."); } boolean seektolastpassed = false; for (iterator.seektolast(); iterator.isvalid(); iterator.prev()) { iterator.status(); assert (iterator.key() != null); assert (iterator.value() != null); seektolastpassed = true; } if (seektolastpassed) { system.out.println("iterator seektolastpassed tests passed."); } iterator.seektofirst(); iterator.seek(iterator.key()); assert (iterator.key() != null); assert (iterator.value() != null); system.out.println("iterator seek test passed."); } system.out.println("iterator tests passed."); final list<byte[]> keys = new arraylist<>(); try (final rocksiterator iterator = db.newiterator()) { for (iterator.seektolast(); iterator.isvalid(); iterator.prev()) { keys.add(iterator.key()); } } map<byte[], byte[]> values = db.multiget(keys); assert (values.size() == keys.size()); for (final byte[] value1 : values.values()) { assert (value1 != null); } values = db.multiget(new readoptions(), keys); assert (values.size() == keys.size()); for (final byte[] value1 : values.values()) { assert (value1 != null); } } catch (final rocksdbexception e) { system.err.println(e); } } }} |
以上就是本次給大家介紹的java中rocksdb安裝與應(yīng)用的全部?jī)?nèi)容，如果大家在學(xué)習(xí)后還有任何不明白的可以在下方的留言區(qū)域討論，感謝對(duì)服務(wù)器之家的支持。
原文鏈接：https://my.oschina.net/yu8huan/blog/1590900
