Apache Dubbo的@SPI接口应用

小灰灰 2024-04-23 02:34 52阅读 0赞

**记录**：472

**场景**：使用Apache Dubbo的@SPI接口加载实现类搭建框架。

**版本**：JDK 1.8,dubbo-common-3.0.0。

SPI全称Service Provider Interface。

**1.基础**

**1.1引用依赖**

<dependency>
      <groupId>org.apache.dubbo</groupId>
      <artifactId>dubbo-common</artifactId>
      <version>3.0.0</version>
    </dependency>

**1.2应用**

(1)使用@SPI注解作用在自定义接口com.hub.example.pf.adapter.IPfDataAdapter。

(2)业务类TCityAdapterImpl、TProvinceAdapterImpl等实现接口IPfDataAdapter。

(3)在..\\src\\main\\resources目录下，新建\\META-INF\\services目录

(4)在\\META-INF\\services目录新建配置文件：com.hub.example.pf.adapter.IPfDataAdapter，文件名称就是@SPI注解作用的接口全路径名称。

(5)在\\META-INF\\services\\com.hub.example.pf.adapter.IPfDataAdapter配置文件中添加入下内容(key=value键值对)：

t_province=com.hub.example.process.adapter.TProvinceAdapterImpl
    t_city=com.hub.example.process.adapter.TCityAdapterImpl

(6)根据配置文件中key名称和接口名称获取实现类，如下：

IPfDataAdapter var= ExtensionLoader.getExtensionLoader(IPfDataAdapter.class).getExtension(tableName);

**1.3逻辑**

Apache Dubbo框架对使用@SPI注解接口，会在..\\src\\main\\resources\\META-INF\\services目录下扫描配置并加载。

**2.示例场景**

(1)从某数据源(比如数据库)中读取数据存放在：Map<String, Object> data。

(2)组装成Tuple3<String, String, Map<String, Object>> in数据格式，其中Tuple3第一个参数数：表名称，第二参数：指定的字段名称，第三个参数就是数据。

(3)使用计算框架com.hub.example.pf.function.PfDataMapFunction计算业务

输入：Tuple3<String, String, Map<String, Object>> in；

输出：Tuple3<String, String, Map<String, String>> out；

(4)把Tuple3<String, String, Map<String, String>> out传递给下游处理。比如数据写入到HBase等目的端。

**3.示例代码**

**3.1接口和抽象类**

**(1)接口****IPfDataAdapter**

全称：com.hub.example.pf.adapter.IPfDataAdapter

代码：

@SPI
    public interface IPfDataAdapter {
        Tuple3<String, String, Map<String, String>> getPfData(Map<String, Object> value);
    }

**(2)抽象类**

全称：com.hub.example.pf.adapter.PfDataAdapterAbstract

代码：

public abstract class PfDataAdapterAbstract implements IPfDataAdapter {
        public PfDataAdapterAbstract() {
        }
        public Tuple3<String, String, Map<String, String>> getPfData(Map<String, Object> data) {
            try {
                Map<String, String> result = new HashMap(data.size());
                for (Map.Entry<String, Object> entry : data.entrySet()) {
                    if (entry.getValue() != null) {
                        result.put(entry.getKey(), entry.getValue().toString());
                    }
                }
                return new Tuple3(this.getTableName(), this.getRowKeyColumns(), result);
            } catch (Exception e) {
                return new Tuple3(null, null, new HashMap<>());
            }
        }
        public abstract String getDataType();
        public String getTableName() {
            return TableConfig.getTableName(this.getDataType());
        }
        public String getRowKeyColumns() {
            return TableConfig.getRowKeyColumns(this.getDataType());
        }
    }

**3.2计算框架**

全称：com.hub.example.pf.function.PfDataMapFunction

代码：

public class PfDataMapFunction {
        public PfDataMapFunction() {
        }
        public Tuple3<String, String, Map<String, String>> map(Tuple3<String, String, Map<String, Object>> data) {
            try {
                String tableName = (String) data.f0;
                IPfDataAdapter dataAdapter = ExtensionLoader.getExtensionLoader(IPfDataAdapter.class).getExtension(tableName);
                if (dataAdapter == null) {
                    return new Tuple3();
                } else {
                    return dataAdapter.getPfData((Map) data.f2);
                }
            } catch (Exception e) {
                e.printStackTrace();
                return new Tuple3();
            }
        }
    }

**3.3业务类**

**(1)业务类TProvinceAdapterImpl对应表：t\_province**

全称：com.hub.example.process.adapter.TProvinceAdapterImpl

代码：

public class TProvinceAdapterImpl extends PfDataAdapterAbstract {
        public TProvinceAdapterImpl() {
        }
        @Override
        public String getDataType() {
            return "T_PROVINCE";
        }
        public Tuple3<String, String, Map<String, String>> getPfData(Map<String, Object> data) {
            if (data.get("PROVINCE_ID") == null) {
                return new Tuple3();
            }
            return super.getPfData(data);
        }
    }

**(2)业务类TCityAdapterImpl对应表：t\_city**

全称：com.hub.example.process.adapter.TCityAdapterImpl

代码：

public class TCityAdapterImpl extends PfDataAdapterAbstract {
        @Override
        public String getDataType() {
            return "T_CITY";
        }
    
        public Tuple3<String, String, Map<String, String>> getPfData(Map<String, Object> data) {
            if (data.get("CITY_ID") == null) {
                return new Tuple3();
            }
            return super.getPfData(data);
        }
    }

**3.4配置文件**

**(1)配置目录..**\\META-INF\\services

目录：..\\src\\main\\resources\\META-INF\\services

**(2)配置文件com.hub.example.pf.adapter.IPfDataAdapter**

文件名：com.hub.example.pf.adapter.IPfDataAdapter

文件内容：

t_province=com.hub.example.process.adapter.TProvinceAdapterImpl
    t_city=com.hub.example.process.adapter.TCityAdapterImpl

**3.5配置类**

全称：com.hub.example.config.TableConfig

代码：

public class TableConfig {
        private static ConcurrentHashMap<String, String> tableConfig = new ConcurrentHashMap<>();
        static {
            tableConfig.put("TABLE:T_PROVINCE", "HUB:T_PROVINCE");
            tableConfig.put("ROW_KEY:T_PROVINCE", "V_DATA_DATE,PROVINCE_ID");
            tableConfig.put("TABLE:T_CITY", "HUB:T_CITY");
            tableConfig.put("ROW_KEY:T_CITY", "V_DATA_DATE,CITY_ID");
        }
        public static String getTableName(String tableName) {
            return tableConfig.get("TABLE:" + tableName.toUpperCase());
        }
        public static String getRowKeyColumns(String tableName) {
            return tableConfig.get("ROW_KEY:" + tableName.toUpperCase());
        }
    }

**3.6实体类**

全称：com.hub.example.api.Tuple3

代码：

public class Tuple3<T0, T1, T2> implements Serializable {
        private static final long serialVersionUID = 1L;
        public T0 f0;
        public T1 f1;
        public T2 f2;
    
        public Tuple3() {
        }
    
        public Tuple3(T0 f0, T1 f1, T2 f2) {
            this.f0 = f0;
            this.f1 = f1;
            this.f2 = f2;
        }
    
        public static String arrayAwareToString(Object o) {
            String arrayString = Arrays.deepToString(new Object[]{o});
            return arrayString.substring(1, arrayString.length() - 1);
        }
    
        public String toString() {
            return "(" + arrayAwareToString(this.f0) + ";" + arrayAwareToString(this.f1) + ";" + arrayAwareToString(this.f2) + ")";
        }
    }

**4.示例测试**

全称：com.hub.example.process.ExampleApplicationSPI

代码：

public class ExampleApplicationSPI {
        public static void main(String[] args) throws Exception {
            PfDataMapFunction dataPfMapFunction = new PfDataMapFunction();
            //操作t_province
            String table01 = "t_province";
            Map<String, Object> data01 = getTProvince();
            Tuple3<String, String, Map<String, Object>> in01 = new Tuple3(table01, data01.get("PROVINCE_ID"), data01);
            Tuple3<String, String, Map<String, String>> out01 = dataPfMapFunction.map(in01);
            System.out.println("操作表t_province后数据: " + out01.toString());
            //操作t_city
            String table02 = "t_city";
            Map<String, Object> data02 = getTCity();
            Tuple3<String, String, Map<String, Object>> in02 = new Tuple3(table02, data02.get("CITY_ID"), data02);
            Tuple3<String, String, Map<String, String>> out02 = dataPfMapFunction.map(in02);
            System.out.println("操作表t_city后数据: " + out02.toString());
        }
        public static Map<String, Object> getTProvince() {
            Map<String, Object> dataMap = new HashMap<>();
            dataMap.put("PROVINCE_ID", 33001694333578181L);
            dataMap.put("V_DATA_DATE", "20230910");
            dataMap.put("PROVINCE_NAME", "浙江");
            dataMap.put("GROSS", 7.77D);
            return dataMap;
        }
        public static Map<String, Object> getTCity() {
            Map<String, Object> dataMap = new HashMap<>();
            dataMap.put("CITY_ID", 33011694333578181L);
            dataMap.put("V_DATA_DATE", "20230911");
            dataMap.put("CITY_NAME", "杭州");
            dataMap.put("GROSS", 1.88D);
            return dataMap;
        }
    }

以上，感谢。

2023年9月10日