/**
* 用BaseAPI保存和获取数据
* @author mengyang
*
*/
public class HelloWorldByBaseAPI {
private File file = new File("C:/Users/mengyang/workspace/je");
private Environment env;
private Database database;
//建立环境
private void setUp(){
EnvironmentConfig envConfig = new EnvironmentConfig();
envConfig.setAllowCreate(true);
env = new Environment(file, envConfig);
DatabaseConfig dbConfig = new DatabaseConfig();
dbConfig.setAllowCreate(true);
database = env.openDatabase(null, "baseAPIDemo", dbConfig);
}
//保存数据
private void save(){
String key = "BaseAPI";
String value = "Hello World!";
try {
DatabaseEntry keyEntry = new DatabaseEntry(key.getBytes("utf-8"));//键
DatabaseEntry valueEntry = new DatabaseEntry(value.getBytes("utf-8"));//值
database.put(null, keyEntry, valueEntry);//保存键值对
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
//检索数据
private void get(){
String key = "BaseAPI";
String value;
try {
DatabaseEntry keyEntry = new DatabaseEntry(key.getBytes("utf-8"));//键
DatabaseEntry valueEntry = new DatabaseEntry();//空的值
if(database.get(null, keyEntry, valueEntry, LockMode.DEFAULT) == OperationStatus.SUCCESS){//根据键来查找
value = new String(valueEntry.getData(), "utf-8");//找到了对于的值
System.out.println("key:BaseAPI,value:"+value);
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
//关闭环境
private void shutDown(){
database.close();
env.close();
}
/**
* @param args
*/
public static void main(String[] args) {
HelloWorldByBaseAPI myCase = new HelloWorldByBaseAPI();
myCase.setUp();
myCase.save();
myCase.get();
myCase.shutDown();
}
}
BerkeleyDB-JE Hello World(使用BaseAPI)
在进一步介绍JE之前,我们先看个BaseAPI版的Hello World,这个例子演示了JE最一般的使用方法,打开环境和Database,持久化数据,查询数据,关闭环境和Database。
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