使用Ignite进行关联查询

1.首先定义两个实体类
(1)订单

public class BatchEntity {
    @QuerySqlField
    private Long id;
    
    @QuerySqlField
    private String bccode;

    @QuerySqlField
    private String customercode;

    @QuerySqlField
    private String countrycode;
    //需要加上getset防范这里省略
}

(2)访销数据

public class BatchEntity {
    @QuerySqlField
    private Long id;

    @QuerySqlField
    private String bccode;

    @QuerySqlField
    private String customercode;

    @QuerySqlField
    private String countrycode;
    //也需要加上getset方法
}

注意创建实体的时候需要通过注解 @QuerySqlField,对实体中的属性进行设置.这样在后面的操作中,可以直接写sql语句进行查询.

(3)定义一个入口启动类,这里我叫做AppMain,在这个类中,我们进行关联统计操作.

public static void main(String args[]) {

        try {
            //连接ignite
            Ignite ignite = Ignition.start();
            //获取订单数据实体
            IgniteCache orderconf = getOrderEntries(ignite);
            //获取访销数据实体
            IgniteCache batchconf = getBatchEntries(ignite);
                            
            //查询sql
            SqlFieldsQuery sql = new SqlFieldsQuery(
                    "select count(*) from BatchEntity  as ba join OR.OrderEntity as or on ba.countrycode = or.countrycode"//126204
//                  "select count(*) from OrderEntity as or join BA.BatchEntity as ba on or.countrycode= ba.countrycode "//126204

            );
            FieldsQueryCursor> lists = batchconf.query(sql);
//            FieldsQueryCursor> lists = orderconf.query(sql);


            System.out.println("查询结果");
            lists.forEach(line -> {
                System.out.println(line);
            });

        } catch (Exception e) {
            e.printStackTrace();
        }
    }


    //获取访销数据的Igniteconf
    private static IgniteCache getOrderEntries(Ignite ignite) throws IOException {
        CacheConfiguration conf = new CacheConfiguration<>();
        conf.setName("OR");
        conf.setCacheMode(CacheMode.PARTITIONED);
        conf.setIndexedTypes(Long.class, OrderEntity.class);

        IgniteCache ordercof = ignite.getOrCreateCache(conf);

        //封装对象
        List orderlist = FileUtils.readLines(new File("./src/main/resources/order.txt"), "utf-8");
        List orderEntityList = Lists.newArrayList();
        AtomicLong batchAtomic = new AtomicLong(0);

        for (String s : orderlist) {
            String[] split = s.split("\t");
            Long id = batchAtomic.getAndIncrement();
            String countrycode = split[0];
            String adate = split[1];
            String amount = split[2];
            OrderEntity orderEntity = new OrderEntity(id, countrycode, adate, Integer.parseInt(amount));
            orderEntityList.add(orderEntity);
        }
        orderEntityList.forEach(orderEntity -> {
            ordercof.put(orderEntity.getId(), orderEntity);
        });
        return ordercof;
    }

    //获取访销数据的Igniteconf
    private static IgniteCache getBatchEntries(Ignite ignite) throws IOException {
        CacheConfiguration conf = new CacheConfiguration<>();
        conf.setName("BA");
        conf.setCacheMode(CacheMode.PARTITIONED);
        conf.setIndexedTypes(Long.class, BatchEntity.class);

        IgniteCache batchconf = ignite.getOrCreateCache(conf);

        //封装对象
        List orderlist = FileUtils.readLines(new File("./src/main/resources/data.txt"), "utf-8");
        List batchEntityList = Lists.newArrayList();
        AtomicLong batchAtomic = new AtomicLong(0);


        for (String s : orderlist) {
            String[] split = s.split("\t");
            Long id = batchAtomic.getAndIncrement();
            String bccode = split[0];
            String customercode = split[1];
            String countrycode = split[2];
            BatchEntity orderEntity = new BatchEntity(id, bccode, customercode, countrycode);
            batchEntityList.add(orderEntity);
        }
        batchEntityList.forEach(batchEntity -> {
            batchconf.put(batchEntity.getId(), batchEntity);
        });
        return batchconf;
    }

在main方法中就可以通过sql语句进行查询,查询的字段就是实体中定义的字段,也可以理解为存储在Ignite表中的列名.

这里说一个注意事项:

 "select count(*) from BatchEntity  as ba join OR.OrderEntity as or on ba.countrycode = or.countrycode"//126204

在执行上面的sql语句的会后,总是出现找不到表的情况.但是我的实体明明是存在的.湿了很多次,发现进行关联的时候,你选择的conf要注意,我们获取的conf有两个,通过两个方法获取的

   IgniteCache orderconf = getOrderEntries(ignite);
   IgniteCache batchconf = getBatchEntries(ignite);

当你需要通过订单表order关联访销表batch的时候,你要使用的是订单的conf—orderconf去执行query()方法
并且, 在 join的表前面需要加上你设置的name --BA,

否则就会找不到表,出现下面的异常. 反过来也是一样,如果你用访销表batch去关联订单表order的时候,需要用batchconf去执行query()方法. 同样需要在join 的订单表前加上你设置的名字OR.
在join前是不需要加别名.但是感觉加上也没有影响.应该不会报错,你们可以自己试试.

javax.cache.CacheException: Failed to parse query. Table "ORDERENTITY" not found; SQL statement:

以上就是最近看ignite的一些心得.希望对你们有所帮助.