点击创建并查询二进制缓存

Question

我想在运行时使用BinaryObjects创建缓存。例如，我不需要编写pojo类（如Employee）并将其配置为缓存值类型，而需要能够使用特定缓存的字段名称和字段类型动态配置缓存。

下面是一些示例代码：

public class EmployeeQuery { 

public static void main(String[] args) throws Exception { 
    Ignition.setClientMode(true); 
    try (Ignite ignite = Ignition.start("examples/config/example-ignite.xml")) { 
     if (!ExamplesUtils.hasServerNodes(ignite)) 
      return; 
     CacheConfiguration<Integer, BinaryObject> cfg = getbinaryCache("emplCache", 1); 
     ignite.destroyCache(cfg.getName()); 
     try (IgniteCache<Integer, BinaryObject> emplCache = ignite.getOrCreateCache(cfg)) { 

      SqlFieldsQuery top5Qry = new SqlFieldsQuery("select * from Employee where salary > 500 limit 5", true); 
      while (true) { 
       QueryCursor<List<?>> top5qryResult = emplCache.query(top5Qry); 

        System.out.println(">>> Employees "); 
        List<List<?>> all = top5qryResult.getAll(); 
        for (List<?> list : all) { 
         System.out.println("Top 5 query result : "+list.get(0) + " , "+ list.get(1) + " , " + list.get(2)); 
        } 
        System.out.println("..... "); 
       Thread.sleep(5000); 
      } 
     } 
     finally { 
      ignite.destroyCache(cfg.getName()); 
     } 
    } 
} 

private static QueryEntity createEmployeeQueryEntity() { 
    QueryEntity employeeEntity = new QueryEntity(); 
    employeeEntity.setTableName("Employee"); 
    employeeEntity.setValueType(BinaryObject.class.getName()); 
    employeeEntity.setKeyType(Integer.class.getName()); 
    LinkedHashMap<String, String> fields = new LinkedHashMap<>(); 

    fields.put("id", Integer.class.getName()); 
    fields.put("firstName", String.class.getName()); 
    fields.put("lastName", String.class.getName()); 
    fields.put("salary", Float.class.getName()); 
    fields.put("gender", String.class.getName()); 

    employeeEntity.setFields(fields); 
    employeeEntity.setIndexes(Arrays.asList(
     new QueryIndex("id"), 
     new QueryIndex("firstName"), 
     new QueryIndex("lastName"), 
     new QueryIndex("salary"), 
     new QueryIndex("gender") 
    )); 

    return employeeEntity; 
} 

public static CacheConfiguration<Integer, BinaryObject> getbinaryCache(String cacheName, int duration) { 
    CacheConfiguration<Integer, BinaryObject> cfg = new CacheConfiguration<>(cacheName); 
    cfg.setCacheMode(CacheMode.PARTITIONED); 
    cfg.setName(cacheName); 
    cfg.setStoreKeepBinary(true); 
    cfg.setAtomicityMode(CacheAtomicityMode.ATOMIC); 
    cfg.setIndexedTypes(Integer.class, BinaryObject.class); 
    cfg.setExpiryPolicyFactory(FactoryBuilder.factoryOf(new CreatedExpiryPolicy(new Duration(SECONDS, duration)))); 
    cfg.setQueryEntities(Arrays.asList(createEmployeeQueryEntity())); 
    return cfg; 
} 

} 

我想配置与雇员（整数）作为关键和整个员工记录（BinaryObject）的值缓存。当我运行上述课程时，出现以下例外情况：

Caused by: org.h2.jdbc.JdbcSQLException: Table "EMPLOYEE" not found; SQL statement: 
select * from "emplCache".Employee where salary > 500 limit 5 

我在做什么错在这里？还有什么比这行更多：

employeeEntity.setTableName("Employee"); 

接下来，我想流数据到缓存中。这是做到这一点的正确方法吗？

public class CsvStreamer { 

public static void main(String[] args) throws IOException { 
    Ignition.setClientMode(true); 

    try (Ignite ignite = Ignition.start("examples/config/example-ignite.xml")) { 
     if (!ExamplesUtils.hasServerNodes(ignite)) 
      return; 
     CacheConfiguration<Integer, BinaryObject> cfg = EmployeeQuery.getbinaryCache("emplCache", 1); 
     try (IgniteDataStreamer<Integer, BinaryObject> stmr = ignite.dataStreamer(cfg.getName())) { 
      while (true) { 
       InputStream in = new FileInputStream(new File(args[0])); 
       try (LineNumberReader rdr = new LineNumberReader(new InputStreamReader(in))) { 
        int count =0; 
        for (String line = rdr.readLine(); line != null; line = rdr.readLine()) { 
         String[] words = line.split(","); 
         BinaryObject emp = getBinaryObject(words); 

         stmr.addData(new Integer(words[0]), emp); 
         System.out.println("Sent data "+count++ +" , sal : "+words[6]); 
        } 
       } 
      } 
     } 
    } 
} 

private static BinaryObject getBinaryObject(String[] rawData) { 
    BinaryObjectBuilder builder = Ignition.ignite().binary().builder("Employee"); 
    builder.setField("id", new Integer(rawData[0])); 
    builder.setField("firstName", rawData[1]); 
    builder.setField("lastName", rawData[2]); 
    builder.setField("salary", new Float(rawData[6])); 
    builder.setField("gender", rawData[4]); 
    BinaryObject binaryObj = builder.build(); 
    return binaryObj; 
} 

} 

注：我正在集群模式下运行此。 EmployeeQuery和CsvStreamer我都是从一台机器运行的，而且我已经在其他两台机器上以服务器模式启动。理想情况下，我想避免在我的应用程序中使用Pojo类，并尽可能使其具有动态性和通用性。

Answer 1

您收到此异常，因为你没有配置SQL方案。在你的情况下（你不想创建pojo对象等），我推荐使用像syntacsis这样的SQL，它自2.0版本以来被添加到Apache Ignite中。我相信下面的例子可以帮助您进行配置：https://github.com/apache/ignite/blob/master/examples/src/main/java/org/apache/ignite/examples/datagrid/CacheQueryDdlExample.java