BerkeleyDB使用的一个简单封装

最新推荐文章于 2021-04-05 14:55:09 发布

wx95com

最新推荐文章于 2021-04-05 14:55:09 发布

阅读量472

点赞数

分类专栏： JAVA 文章标签： string import exception byte null path

JAVA 专栏收录该内容

11 篇文章

订阅专栏

本文介绍了一个使用Berkeley DB实现的简单Java类，该类提供了获取、插入、更新和删除记录的基本功能。通过实例演示了如何设置数据库环境、打开数据库以及进行基本的CRUD操作。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

001package 
db; 

002  

003import 
java.io.File; 

004import 
com.sleepycat.je.Database; 

005import 
com.sleepycat.je.DatabaseConfig; 

006import 
com.sleepycat.je.DatabaseEntry; 

007import 
com.sleepycat.je.DatabaseException; 

008import 
com.sleepycat.je.Environment; 

009import 
com.sleepycat.je.EnvironmentConfig; 

010import 
com.sleepycat.je.LockMode; 

011import 
com.sleepycat.je.OperationStatus; 

012  

013public 
class BerkeleyDB { 

014    private
Environment env; 

015    private
Database db; 

016  

017    public
BerkeleyDB(String path, String dbName) { 

018        setUp(path,
1000000); 

019        open(dbName);

020    } 

021  

022    public
String get(String key) throws
Exception { 

023        byte[] theKey = key.getBytes();

024        DatabaseEntry queryKey =
new DatabaseEntry(theKey);

025        DatabaseEntry value =
new DatabaseEntry();

026  

027        OperationStatus status = db

028                .get(null, queryKey, value, LockMode.DEFAULT);

029        if
(status == OperationStatus.SUCCESS) { 

030            return
new String(value.getData());

031        }

032        return
null; 

033    } 

034  

035    public
boolean put(String key, String value)
throws Exception {

036        byte[] theKey = key.getBytes();

037        byte[] theValue = value.getBytes();

038        OperationStatus status = db.putNoOverwrite(null,
new DatabaseEntry(

039                theKey),
new DatabaseEntry(theValue));

040        if
(status == OperationStatus.SUCCESS) { 

041            return
true; 

042        }

043        return
false; 

044    } 

045  

046    public
boolean delete(String key)
throws Exception {

047        byte[] theKey = key.getBytes();

048        OperationStatus status = db.delete(null,
new DatabaseEntry(theKey));

049        if
(status == OperationStatus.SUCCESS) { 

050            return
true; 

051        }

052        return
false; 

053    } 

054  

055    public
boolean update(String key, String value)
throws Exception {

056        byte[] updateKey = key.getBytes();

057        byte[] updateValue = value.getBytes();

058  

059        OperationStatus status = db.put(null,
new DatabaseEntry(updateKey),

060                new
DatabaseEntry(updateValue)); 

061        if
(status == OperationStatus.SUCCESS) { 

062            return
true; 

063        }

064        return
false; 

065    } 

066  

067    public
void close() { 

068        try
{ 

069            if
(db != null) {

070                db.close();

071            }

072            if
(env != null) {

073                env.close();

074            }

075        }
catch (DatabaseException e) {

076            e.printStackTrace();

077        }

078    } 

079  

080    private
void setUp(String path,
long cacheSize) {

081        EnvironmentConfig envConfig =
new EnvironmentConfig();

082        envConfig.setAllowCreate(true);

083        envConfig.setCacheSize(cacheSize);

084        try
{ 

085            env =
new Environment(new
File(path), envConfig); 

086        }
catch (DatabaseException e) {

087            e.printStackTrace();

088        }

089    } 

090  

091    private
void open(String dbName) {

092        DatabaseConfig dbConfig =
new DatabaseConfig();

093        dbConfig.setAllowCreate(true);

094        try
{ 

095            db = env.openDatabase(null, dbName, dbConfig);

096        }
catch (DatabaseException e) {

097            e.printStackTrace();

098        }

099    } 

100}