学步园

一个很不错的Java嵌入式数据库。下面的代码展示了一下用法。如果只是当个Map来用应该是够了。

package bdb;<br /> import java.io.File;<br /> import java.io.IOException;<br /> import com.sleepycat.je.Database;<br /> import com.sleepycat.je.DatabaseConfig;<br /> import com.sleepycat.je.DatabaseEntry;<br /> import com.sleepycat.je.Environment;<br /> import com.sleepycat.je.EnvironmentConfig;<br /> import com.sleepycat.je.LockMode;<br /> import com.sleepycat.je.OperationStatus;<br /> import com.sleepycat.je.Transaction;<br /> /**<br /> * 一个简单的Bdb Map<br /> *<br /> * @author Shixiong Zhu<br /> */<br /> public class Bdb {<br /> private Environment env;<br /> private Database database;<br /> private Transaction txn;<br /> public Bdb(String envDirName, String databaseName) throws IOException {<br /> txn = null;<br /> EnvironmentConfig configuration = new EnvironmentConfig();<br /> configuration.setAllowCreate(true);<br /> File envDir = new File(envDirName);<br /> if (!envDir.exists()) {<br /> if (!envDir.mkdirs()) {<br /> throw new IOException("create directory " + envDirName<br /> + " fail");<br /> }<br /> } else {<br /> if (envDir.isFile()) {<br /> throw new IOException(envDirName + " must be a directory");<br /> }<br /> }<br /> env = new Environment(envDir, configuration);<br /> DatabaseConfig dbConfig = new DatabaseConfig();<br /> dbConfig.setAllowCreate(true);<br /> database = env.openDatabase(txn, databaseName, dbConfig);<br /> }<br /> public void put(BdbEntry key, BdbEntry value) {<br /> DatabaseEntry keyEntry = new DatabaseEntry(key.getBytes());<br /> DatabaseEntry valueEntry = new DatabaseEntry(value.getBytes());<br /> database.put(txn, keyEntry, valueEntry);<br /> }<br /> public boolean get(BdbEntry key, BdbEntry value) {<br /> DatabaseEntry keyEntry = new DatabaseEntry(key.getBytes());<br /> DatabaseEntry valueEntry = new DatabaseEntry();<br /> OperationStatus status = database.get(txn, keyEntry, valueEntry,<br /> LockMode.DEFAULT);<br /> if (status == OperationStatus.SUCCESS) {<br /> value.setBytes(valueEntry.getData());<br /> return true;<br /> } else {<br /> return false;<br /> }<br /> }<br /> public void close() {<br /> database.close();<br /> env.cleanLog();<br /> env.close();<br /> }<br /> public static interface BdbEntry {<br /> public byte[] getBytes();<br /> public void setBytes(byte[] bytes);<br /> }<br /> }<br />