Java调用Geode

Goede序列化

Geode提供了Java序列化之外的序列化选项，为数据存储，传输和语言类型提供更高的性能和更大的灵活性。 

Geode DataSerialization 比PDXSerialization快 25％，但使用PDX序列化可以减少反序列化的成本。 

Geode 提供的序列化方式（DataSerialization和PDXSerialization），不支持对象的循环引用，如果多次引用相同的对象，则会将每个引用进行序列化，反序列化会生成对象的多个副本。在这种情况下，Java序列化对象一次，当对象进行反序列化时，它将生成具有多个引用的对象的实例。 

Java连接Geode示例

依赖JAR：

<dependency>
<groupId>org.apache.geode</groupId>
<artifactId>geode-core</artifactId>
<version>1.1.0</version>
</dependency>

<dependency>
<groupId>com.gemstone.gemfire</groupId>
<artifactId>gemfire</artifactId>
<version>8.2.2</version>
</dependency>

<dependency>
<groupId>org.apache.geode</groupId>
<artifactId>geode-json</artifactId>
<version>1.1.0</version>
</dependency>
<dependency>
<groupId>org.apache.geode</groupId>
<artifactId>geode-common</artifactId>
<version>1.1.0</version>
</dependency>

代码示例：

public class UserEntity implements Serializable{

private int id;
private int age;
private String name;
private Date registerdDate;

//getter and setter...
}

public class DataClient {
private final static Logger logger  = Logger.getLogger(DataClient.class);

Region region = null;
@Before
public void init(){
ClientCache cache = new ClientCacheFactory().addPoolLocator("db", 10334).create();
ClientRegionFactory rf = cache.createClientRegionFactory(ClientRegionShortcut.CACHING_PROXY);

region = rf.create( "user");
}

@Test
public void saveUserEntity(){
region.putAll(newUserEntity(10));
}

@Test
public void clear(){
region.clear();
}

@Test
public void delele(){
region.remove("");
}

@Test
public void update(){
Object obj = region.get("108");
Map<String, UserEntity> map = new HashMap<String, UserEntity>();
UserEntity data= ((UserEntity)obj);
data.setAge(12);
map.put("108",data);
region.putAll(map);
}

@Test
public void getUserEntity(){
try {
Object objList = region.query("select * from /user u where u.age > 10");
Object obj = region.get("108");
if(objList != null && objList instanceof ResultsBag){
Iterator iter = ((ResultsBag) objList).iterator();
while(iter.hasNext()){
UserEntity UserEntity = (UserEntity) iter.next();
System.out.println("UserEntity"+UserEntity);
}
}
if(obj != null && obj instanceof UserEntity){
System.out.println("UserEntity"+(UserEntity)obj);
}
}catch (Exception e){
logger.error("error occured.", e);
}
}

@After
public void done(){
region.close();
}

private Map<Integer, UserEntity> newUserEntity(int size){
Map<Integer, UserEntity> map = new HashMap<Integer, UserEntity>();
for (int i = 0; i < size; i++) {
int id = i+100;
map.put(id,new UserEntity(id,10+i,"username:"+id,new Date()));
}
return map;
}
}

Geode Query

查询示例

// Identify your query string.
String queryString = "SELECT * FROM /exampleRegion";

// Get QueryService from Cache.
QueryService queryService = cache.getQueryService();

// Create the Query Object.
Query query = queryService.newQuery(queryString);

// Execute Query locally. Returns results set.
SelectResults results = (SelectResults)query.execute();

// Find the Size of the ResultSet.
int size = results.size();

// Iterate through your ResultSet.
Portfolio p = (Portfolio)results.iterator().next(); /* Region containing Portfolio object. */

查询语法

WHERE 语法 

SELECT * FROM /user WHERE name=‘username’; 

LIKE 语法 

SELECT * FROM /user WHERE name like ‘use%’; 

SELECT * FROM /user WHERE name like ‘_use_’; 

添加表别名 

SELECT u.id,u.name FROM /user u WHERE u.name=‘username’; 

DISTINCT 

SELECT DISTINCT u.name FROM /user u 

逻辑操作符 AND,OR,NOT 

SELECT * FROM /user WHERE id>4 and id<9 and not id = 6 

其它比较操作 

=,<>,!=,<,⇐,>,>= 

IN,NOT IN 

SELECT * FROM /user WHERE NOT (ID IN SET(1,2)) 

LIMIT 

SELECT * FROM /user WHERE id>0 LIMIT 10 

COUNT 

SELECT COUNT(*) FROM /user WHERE ID > 0 LIMIT 50