[Spring cloud 一步步实现广告系统] 15. 使用开源组件监听Binlog 实现增量索引准备

时间:2023-01-02 08:47:20
MySQL Binlog简介
  • 什么是binlog?

一个二进制日志,用来记录对数据发生或潜在发生更改的SQL语句,并以而进行的形式保存在磁盘中。

  • binlog 的作用?

最主要有3个用途:

  • 数据复制(主从同步)

    Mysql 的Master-Slave协议,让Slave可以通过监听binlog实现数据复制,达到数据一致性目的
  • 数据恢复

    通过mysqlbinlog工具恢复数据
  • 增量备份
  • Binlog 变量
    • log_bin (Binlog 开关,使用show variables like 'log_bin';查看)
    • binlog_format (Binlog 日志格式,使用show variables like 'binlog_format';查看)

      日志格式总共有三种:
      • ROW, 仅保存记录被修改的细节,不记录SQL语句上下文相关信息。(能清晰的记录下每行数据的修改细节,不需要记录上下文相关信息,因此不会发生某些特定情况下的procedure、function以及trigger 的调用无法被准确复制的问题,任何情况下都可以被复制,且能加快从库重放日志的效率,保证从库数据的一致性)
      • STATEMENT,每一条修改数据的SQL都会被记录。(只记录执行语句的细节和上下文环境,避免了记录每一行的变化,在一些修改记录较多的情况下,相比ROW类型能大大减少binlog的日志量,节约IO,提高性能。还可以用于实时的还原,同时主从版本可以不一样,从服务器版本可以比主服务器版本高)
      • MIXED, 上述2种的混合使用
  • Binlog 管理
    • show master logs; 查看所有binlog的日志列表
    • show master status; 查看最后一个binlog日志编号名称,以及最后一个事件技术的位置(position)
    • Flush logs; 刷新binlog,此刻开始产生一个新编号的binlog日志文件
    • reset master; 清空所有的binlog日志
  • Binlog 相关SQL show binlog events[in 'log_name'][from position][limit [offset,]row_count]

    [Spring cloud 一步步实现广告系统] 15. 使用开源组件监听Binlog 实现增量索引准备

    [Spring cloud 一步步实现广告系统] 15. 使用开源组件监听Binlog 实现增量索引准备
  • 常用的Binlog event
    • QUERY - 与数据无关的操作,begin、drop table、truncate table等等
    • TABLE_MAP - 记录下一个操作所对应的表信息,存储了数据库名称和表名称
    • XID - 标记事务提交
    • WRITE_ROWS 插入数据,即insert操作
    • UPDATE_ROWS 更新数据,即update操作
    • DELETE_ROWS 删除数据,即delete操作

Event包含header和data两部分,header提供了event的创建时间,哪个服务器等信息,data部分提供的是针对该event的具体信息,如具体数据的修改。

Tip: binlog不会记录数据表的列名

在接下来的实现中,我们会将自己的系统包装成一个假的Mysql Slave,通过开源工具mysql-binlog-connector-java来实现监听binlog。

开源工具mysql-binlog-connector-java
<!-- binlog 日志监听,解析开源工具类库 -->
<dependency>
<groupId>com.github.shyiko</groupId>
<artifactId>mysql-binlog-connector-java</artifactId>
<version>0.18.1</version>
</dependency>

2.创建一个测试接口

package com.sxzhongf.ad.service;

import com.github.shyiko.mysql.binlog.BinaryLogClient;
import com.github.shyiko.mysql.binlog.event.DeleteRowsEventData;
import com.github.shyiko.mysql.binlog.event.EventData;
import com.github.shyiko.mysql.binlog.event.UpdateRowsEventData;
import com.github.shyiko.mysql.binlog.event.WriteRowsEventData; import java.io.IOException; /**
* BinlogServiceTest for 测试Mysql binlog 监控
* {@code
* Mysql8 连接提示 Client does not support authentication protocol requested by server; consider upgrading MySQL client 解决方法
* USE mysql;
* ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';
* FLUSH PRIVILEGES;
* }
*
* @author <a href="mailto:magicianisaac@gmail.com">Isaac.Zhang | 若初</a>
*/
public class BinlogServiceTest { /**
* --------Update-----------
* UpdateRowsEventData{tableId=90, includedColumnsBeforeUpdate={0, 1, 2, 3, 4, 5, 6, 7}, includedColumns={0, 1, 2, 3, 4, 5, 6, 7}, rows=[
* {before=[11, 10, Test Bin Log, 1, Tue Jun 25 08:00:00 CST 2019, Tue Jun 25 08:00:00 CST 2019, Tue Jun 25 08:00:00 CST 2019, Tue Jun 25 08:00:00 CST 2019], after=[11, 10, zhangpan test Binlog, 1, Tue Jun 25 08:00:00 CST 2019, Tue Jun 25 08:00:00 CST 2019, Tue Jun 25 08:00:00 CST 2019, Tue Jun 25 08:00:00 CST 2019]}
* ]}
*
* --------Insert-----------
* WriteRowsEventData{tableId=91, includedColumns={0, 1, 2, 3, 4, 5, 6, 7}, rows=[
* [10, 11, ad unit test binlog, 1, 0, 1236.7655, Thu Jun 27 08:00:00 CST 2019, Thu Jun 27 08:00:00 CST 2019]
* ]}
*/ public static void main(String[] args) throws IOException { // //构造BinaryLogClient,填充mysql链接信息
BinaryLogClient client = new BinaryLogClient("127.0.0.1", 3306,
"root", "12345678"
); //设置需要读取的Binlog的文件以及位置,否则,client会从"头"开始读取Binlog并监听
// client.setBinlogFilename("binlog.000035");
// client.setBinlogPosition(); //给客户端注册监听器,实现对Binlog的监听和解析
//event 就是监听到的Binlog变化信息,event包含header & data 两部分
client.registerEventListener(event -> {
EventData data = event.getData();
if (data instanceof UpdateRowsEventData) {
System.out.println("--------Update-----------");
System.out.println(data.toString());
} else if (data instanceof WriteRowsEventData) {
System.out.println("--------Insert-----------");
System.out.println(data.toString());
} else if (data instanceof DeleteRowsEventData) {
System.out.println("--------Delete-----------");
System.out.println(data.toString());
}
}); client.connect();
}
}

运行:

八月 08, 2019 9:13:32 上午 com.github.shyiko.mysql.binlog.BinaryLogClient connect
信息: Connected to 127.0.0.1:3306 at binlog.000038/951 (sid:65535, cid:336)
...

执行sql update ad_user set user_status=1 where user_id=10;

[Spring cloud 一步步实现广告系统] 15. 使用开源组件监听Binlog 实现增量索引准备

我们需要知道的是,我们的目的是实现对Mysql数据表的变更实现监听,并解析成我们想要的格式,也就是我们的java对象。根据上面我们看到的监听结果,我们知道了返回信息的大概内容,既然我们已经学会了简单的使用BinaryLogClient 来监听binlog,接下来,我们需要定义一个监听器,来实现我们自己的业务内容。

因为我们只需要Event中的内容,那么我们也就只需要通过实现com.github.shyiko.mysql.binlog.BinaryLogClient.EventListener接口,来自定义一个监听器实现我们的业务即可。通过Event的内容,来判定是否需要处理当前event以及如何处理。

构造解析binlog的模版文件

我们监听binlog来构造增量数据的根本原因,是为了将我们的广告投放系统广告检索系统 业务解耦,由于我们的检索系统中没有定义数据库以及数据表的相关,所以,我们通过定义一份模版文件,通过解析模版文件来得到我们需要的数据库和表信息,因为binlog的监听是不区分是哪个数据库和哪个数据表信息的,我们可以通过模版来指定我们想要监听的部分。

{
"database": "advertisement",
"tableList": [
{
"tableName": "ad_plan",
"level": 2,
"insert": [
{
"column": "plan_id"
},
{
"column": "user_id"
},
{
"column": "plan_status"
},
{
"column": "start_date"
},
{
"column": "end_date"
}
],
"update": [
{
"column": "plan_id"
},
{
"column": "user_id"
},
{
"column": "plan_status"
},
{
"column": "start_date"
},
{
"column": "end_date"
}
],
"delete": [
{
"column": "plan_id"
}
]
},
{
"tableName": "ad_unit",
"level": 3,
"insert": [
{
"column": "unit_id"
},
{
"column": "unit_status"
},
{
"column": "position_type"
},
{
"column": "plan_id"
}
],
"update": [
{
"column": "unit_id"
},
{
"column": "unit_status"
},
{
"column": "position_type"
},
{
"column": "plan_id"
}
],
"delete": [
{
"column": "unit_id"
}
]
},
{
"tableName": "ad_creative",
"level": 2,
"insert": [
{
"column": "creative_id"
},
{
"column": "type"
},
{
"column": "material_type"
},
{
"column": "height"
},
{
"column": "width"
},
{
"column": "audit_status"
},
{
"column": "url"
}
],
"update": [
{
"column": "creative_id"
},
{
"column": "type"
},
{
"column": "material_type"
},
{
"column": "height"
},
{
"column": "width"
},
{
"column": "audit_status"
},
{
"column": "url"
}
],
"delete": [
{
"column": "creative_id"
}
]
},
{
"tableName": "relationship_creative_unit",
"level": 3,
"insert": [
{
"column": "creative_id"
},
{
"column": "unit_id"
}
],
"update": [
],
"delete": [
{
"column": "creative_id"
},
{
"column": "unit_id"
}
]
},
{
"tableName": "ad_unit_district",
"level": 4,
"insert": [
{
"column": "unit_id"
},
{
"column": "province"
},
{
"column": "city"
}
],
"update": [
],
"delete": [
{
"column": "unit_id"
},
{
"column": "province"
},
{
"column": "city"
}
]
},
{
"tableName": "ad_unit_hobby",
"level": 4,
"insert": [
{
"column": "unit_id"
},
{
"column": "hobby_tag"
}
],
"update": [
],
"delete": [
{
"column": "unit_id"
},
{
"column": "hobby_tag"
}
]
},
{
"tableName": "ad_unit_keyword",
"level": 4,
"insert": [
{
"column": "unit_id"
},
{
"column": "keyword"
}
],
"update": [
],
"delete": [
{
"column": "unit_id"
},
{
"column": "keyword"
}
]
}
]
}

上面的模版文件中,指定了一个数据库为advertisement,大家可以方便添加多个监听库。在数据库下面,我们监听了几个表的CUD操作以及每个操作所需要的字段信息。

  • 实现模版 —> Java Entity

    • 定义模版文件对应的实体
    @Data
    @AllArgsConstructor
    @NoArgsConstructor
    public class BinlogTemplate {
    //单数据库对应
    private String database;
    //多表
    private List<JsonTable> tableList;
    }
    • 对应的json 中 table信息
    /**
    * JsonTable for 用于表示template.json中对应的表信息
    *
    * @author <a href="mailto:magicianisaac@gmail.com">Isaac.Zhang | 若初</a>
    */
    @Data
    @AllArgsConstructor
    @NoArgsConstructor
    public class JsonTable {
    private String tableName;
    private Integer level; private List<Column> insert;
    private List<Column> update;
    private List<Column> delete; @Data
    @AllArgsConstructor
    @NoArgsConstructor
    public static class Column {
    private String columnName;
    }
    }
    • 读取的对应表信息对象(最主要目的就是为了能将字段索引 映射到 字段名称
    @Data
    @AllArgsConstructor
    @NoArgsConstructor
    public class TableTemplate {
    private String tableName;
    private String level; //操作类型 -> 多列
    private Map<OperationTypeEnum, List<String>> opTypeFieldSetMap = new HashMap<>(); /**
    * Binlog日志中 字段索引 -> 字段名称 的一个转换映射
    * 因为binlog中不会显示更新的列名是什么,它只会展示字段的索引,因此我们需要实现一次转换
    */
    private Map<Integer, String> posMap = new HashMap<>();
    }
    • 解析模版文件到java对象
    @Data
    public class ParseCustomTemplate { private String database; /**
    * key -> TableName
    * value -> {@link TableTemplate}
    */
    private Map<String, TableTemplate> tableTemplateMap; public static ParseCustomTemplate parse(BinlogTemplate _template) {
    ParseCustomTemplate template = new ParseCustomTemplate();
    template.setDatabase(_template.getDatabase()); for (JsonTable jsonTable : _template.getTableList()) {
    String name = jsonTable.getTableName();
    Integer level = jsonTable.getLevel(); TableTemplate tableTemplate = new TableTemplate();
    tableTemplate.setTableName(name);
    tableTemplate.setLevel(level.toString());
    template.tableTemplateMap.put(name, tableTemplate); //遍历操作类型对应的列信息
    Map<OperationTypeEnum, List<String>> operationTypeListMap = tableTemplate.getOpTypeFieldSetMap(); for (JsonTable.Column column : jsonTable.getInsert()) {
    getAndCreateIfNeed(
    OperationTypeEnum.ADD,
    operationTypeListMap,
    ArrayList::new
    ).add(column.getColumnName());
    } for (JsonTable.Column column : jsonTable.getUpdate()) {
    getAndCreateIfNeed(
    OperationTypeEnum.UPDATE,
    operationTypeListMap,
    ArrayList::new
    ).add(column.getColumnName());
    } for (JsonTable.Column column : jsonTable.getDelete()) {
    getAndCreateIfNeed(
    OperationTypeEnum.DELETE,
    operationTypeListMap,
    ArrayList::new
    ).add(column.getColumnName());
    }
    } return template;
    } /**
    * 从Map中获取对象,如果不存在,创建一个
    */
    private static <T, R> R getAndCreateIfNeed(T key, Map<T, R> map, Supplier<R> factory) {
    return map.computeIfAbsent(key, k -> factory.get());
    }
    }
    • 解析 字段索引 -> 字段名称 的一个转换映射

    首先,我们来看一下binlog的具体日志信息:

    --------Insert-----------
    WriteRowsEventData{tableId=91, includedColumns={0, 1, 2, 3, 4, 5, 6, 7}, rows=[
    [10, 11, ad unit test binlog, 1, 0, 1236.7655, Thu Jun 27 08:00:00 CST 2019, Thu Jun 27 08:00:00 CST 2019]
    --------Update-----------
    UpdateRowsEventData{tableId=81, includedColumnsBeforeUpdate={0, 1, 2, 3, 4, 5}, includedColumns={0, 1, 2, 3, 4, 5}, rows=[
    {before=[10, Isaac Zhang, 2D3ABB6F2434109A105170FB21D00453, 0, Fri Jun 21 15:07:53 CST 2019, Fri Jun 21 15:07:53 CST 2019], after=[10, Isaac Zhang, 2D3ABB6F2434109A105170FB21D00453, 1, Fri Jun 21 15:07:53 CST 2019, Fri Jun 21 15:07:53 CST 2019]}

    可以看到,在日志中includedColumns只包含了{0, 1, 2, 3, 4, 5}位置信息,那么我们怎么能知道它具体代表的是哪个字段呢,接下来我们来实现这步映射关系,在实现之前,我们先来查询一下数据库中我们的表中字段所处的具体位置:

    sql> SELECT table_schema,table_name,column_name,ordinal_position FROM information_schema.COLUMNS
    WHERE TABLE_SCHEMA = 'advertisement' AND TABLE_NAME='ad_user'

    [Spring cloud 一步步实现广告系统] 15. 使用开源组件监听Binlog 实现增量索引准备

    我们可以看到ordinal_position对应的是1-6,可是上面监听到的binlog日志索引是0-5,所以我们就可以看出来之间的对应关系。

    我们开始编码实现,我们使用JdbcTemplate进行查询数据库信息:

    @Slf4j
    @Component
    public class TemplateHolder {
    private ParseCustomTemplate template; private final JdbcTemplate jdbcTemplate; private String SQL_SCHEMA = "SELECT TABLE_SCHEMA,TABLE_NAME,COLUMN_NAME,ORDINAL_POSITION FROM information_schema.COLUMNS " +
    "WHERE TABLE_SCHEMA = ? AND TABLE_NAME = ?"; @Autowired
    public TemplateHolder(JdbcTemplate jdbcTemplate) {
    this.jdbcTemplate = jdbcTemplate;
    } /**
    * 需要在容器加载的时候,就载入数据信息
    */
    @PostConstruct
    private void init() {
    loadJSON("template.json");
    } /**
    * 对外提供加载服务
    */
    public TableTemplate getTable(String tableName) {
    return template.getTableTemplateMap().get(tableName);
    } /**
    * 加载需要监听的binlog json文件
    */
    private void loadJSON(String path) {
    ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
    InputStream inputStream = classLoader.getResourceAsStream(path); try {
    BinlogTemplate binlogTemplate = JSON.parseObject(
    inputStream,
    Charset.defaultCharset(),
    BinlogTemplate.class
    ); this.template = ParseCustomTemplate.parse(binlogTemplate);
    loadMeta();
    } catch (IOException ex) {
    log.error((ex.getMessage()));
    throw new RuntimeException("fail to parse json file");
    }
    } /**
    * 加载元信息
    * 使用表索引到列名称的映射关系
    */
    private void loadMeta() {
    for (Map.Entry<String, TableTemplate> entry : template.getTableTemplateMap().entrySet()) {
    TableTemplate table = entry.getValue(); List<String> updateFields = table.getOpTypeFieldSetMap().get(
    OperationTypeEnum.UPDATE
    );
    List<String> insertFields = table.getOpTypeFieldSetMap().get(
    OperationTypeEnum.ADD
    );
    List<String> deleteFields = table.getOpTypeFieldSetMap().get(
    OperationTypeEnum.DELETE
    ); jdbcTemplate.query(SQL_SCHEMA, new Object[]{
    template.getDatabase(), table.getTableName()
    }, (rs, i) -> {
    int pos = rs.getInt("ORDINAL_POSITION");
    String colName = rs.getString("COLUMN_NAME"); if ((null != updateFields && updateFields.contains(colName))
    || (null != insertFields && insertFields.contains(colName))
    || (null != deleteFields && deleteFields.contains(colName))) {
    table.getPosMap().put(pos - 1, colName);
    }
    return null;
    }
    );
    }
    }
    }
    • 监听binlog实现

      • 定义Event 解析所需要转换的java对象
      @Data
      public class BinlogRowData { private TableTemplate tableTemplate; private EventType eventType; private List<Map<String, String>> before; private List<Map<String, String>> after; }
      • 定义binlog client BinaryLogClient
      /**
      * CustomBinlogClient for 自定义Binlog Client
      *
      * @author <a href="mailto:magicianisaac@gmail.com">Isaac.Zhang | 若初</a>
      * @since 2019/6/27
      */
      @Slf4j
      @Component
      public class CustomBinlogClient { private BinaryLogClient client; private final BinlogConfig config;
      private final AggregationListener listener; @Autowired
      public CustomBinlogClient(BinlogConfig config, AggregationListener listener) {
      this.config = config;
      this.listener = listener;
      } public void connect() {
      new Thread(() -> {
      client = new BinaryLogClient(
      config.getHost(),
      config.getPort(),
      config.getUsername(),
      config.getPassword()
      ); if (!StringUtils.isEmpty(config.getBinlogName()) && !config.getPosition().equals(-1L)) {
      client.setBinlogFilename(config.getBinlogName());
      client.setBinlogPosition(config.getPosition());
      } try {
      log.info("connecting to mysql start...");
      client.connect();
      log.info("connecting to mysql done!");
      } catch (IOException e) {
      e.printStackTrace();
      }
      }).start();
      } public void disconnect() {
      try {
      log.info("disconnect to mysql start...");
      client.disconnect();
      log.info("disconnect to mysql done!");
      } catch (IOException e) {
      e.printStackTrace();
      }
      }
      }
      • 使用client注册事件监听器com.github.shyiko.mysql.binlog.BinaryLogClient.EventListener
      /**
      * Ilistener for 为了后续扩展不同的实现
      *
      * @author <a href="mailto:magicianisaac@gmail.com">Isaac.Zhang | 若初</a>
      */
      public interface Ilistener { void register(); void onEvent(BinlogRowData eventData);
      }
      • 监听Binlog, 收集mysql binlog datas
      @Slf4j
      @Component
      public class AggregationListener implements BinaryLogClient.EventListener { private String dbName;
      private String tbName; private Map<String, Ilistener> listenerMap = new HashMap<>(); @Autowired
      private TemplateHolder templateHolder; private String genKey(String dbName, String tbName) {
      return dbName + ":" + tbName;
      } /**
      * 根据表实现注册信息
      */
      public void register(String dbName, String tbName, Ilistener listener) {
      log.info("register : {}-{}", dbName, tbName);
      this.listenerMap.put(genKey(dbName, tbName), listener);
      } @Override
      public void onEvent(Event event) { EventType type = event.getHeader().getEventType();
      log.info("Event type: {}", type); //数据库增删改之前,肯定有一个table_map event 的binlog
      if (type == EventType.TABLE_MAP) {
      TableMapEventData data = event.getData();
      this.tbName = data.getTable();
      this.dbName = data.getDatabase();
      return;
      } //EXT_UPDATE_ROWS 是Mysql 8以上的type
      if (type != EventType.EXT_UPDATE_ROWS
      && type != EventType.EXT_WRITE_ROWS
      && type != EventType.EXT_DELETE_ROWS
      ) {
      return;
      } // 检查表名和数据库名是否已经正确填充
      if (StringUtils.isEmpty(dbName) || StringUtils.isEmpty(tbName)) {
      log.error("Meta data got error. tablename:{},database:{}", tbName, dbName);
      return;
      } //找出对应数据表敏感的监听器
      String key = genKey(this.dbName, this.tbName);
      Ilistener ilistener = this.listenerMap.get(key);
      if (null == ilistener) {
      log.debug("skip {}", key);
      } log.info("trigger event:{}", type.name()); try {
      BinlogRowData rowData = convertEventData2BinlogRowData(event.getData());
      if (null == rowData) {
      return;
      }
      rowData.setEventType(type);
      ilistener.onEvent(rowData); } catch (Exception e) {
      e.printStackTrace();
      log.error(e.getMessage());
      } finally {
      this.dbName = "";
      this.tbName = "";
      }
      } /**
      * 解析Binlog数据到Java实体对象的映射
      *
      * @param data binlog
      * @return java 对象
      */
      private BinlogRowData convertEventData2BinlogRowData(EventData data) {
      TableTemplate tableTemplate = templateHolder.getTable(tbName);
      if (null == tableTemplate) {
      log.warn("table {} not found.", tbName);
      return null;
      } List<Map<String, String>> afterMapList = new ArrayList<>(); for (Serializable[] after : getAfterValues(data)) {
      Map<String, String> afterMap = new HashMap<>(); int columnLength = after.length;
      for (int i = 0; i < columnLength; ++i) {
      //取出当前位置对应的列名
      String colName = tableTemplate.getPosMap().get(i);
      //如果没有,则说明不需要该列
      if (null == colName) {
      log.debug("ignore position: {}", i);
      continue;
      } String colValue = after[i].toString();
      afterMap.put(colName, colValue);
      } afterMapList.add(afterMap);
      } BinlogRowData binlogRowData = new BinlogRowData();
      binlogRowData.setAfter(afterMapList);
      binlogRowData.setTableTemplate(tableTemplate); return binlogRowData;
      } /**
      * 获取不同事件的变更后数据
      * Add & Delete变更前数据假定为空
      */
      private List<Serializable[]> getAfterValues(EventData eventData) { if (eventData instanceof WriteRowsEventData) {
      return ((WriteRowsEventData) eventData).getRows();
      } if (eventData instanceof UpdateRowsEventData) {
      return ((UpdateRowsEventData) eventData).getRows()
      .stream()
      .map(Map.Entry::getValue)
      .collect(Collectors.toList()
      );
      } if (eventData instanceof DeleteRowsEventData) {
      return ((DeleteRowsEventData) eventData).getRows();
      } return Collections.emptyList();
      }
      }
      • 解析binlog 数据对象BinlogRowData ,用于增量索引的后续处理
      /**
      * MysqlRowData for 简化{@link BinlogRowData} 以方便实现增量索引的实现
      *
      * @author <a href="mailto:magicianisaac@gmail.com">Isaac.Zhang | 若初</a>
      */
      @Data
      @AllArgsConstructor
      @NoArgsConstructor
      public class MysqlRowData { //实现多数据的时候,需要传递数据库名称
      //private String database;
      private String tableName;
      private String level;
      private OperationTypeEnum operationTypeEnum;
      private List<Map<String, String>> fieldValueMap = new ArrayList<>();
      }

      因为我们需要将Binlog EventType转换为我们的操作类型OperationTypeEnum,所以,我们在OperationTypeEnum中添加一个转换方法:

      public enum OperationTypeEnum {
      ...
      public static OperationTypeEnum convert(EventType type) {
      switch (type) {
      case EXT_WRITE_ROWS:
      return ADD;
      case EXT_UPDATE_ROWS:
      return UPDATE;
      case EXT_DELETE_ROWS:
      return DELETE;
      default:
      return OTHER;
      }
      }
      }

      我们还需要定义一个表包含的各个列名称的java类,方便我们后期对数据表的CUD操作:

      package com.sxzhongf.ad.mysql.constant;
      
      import java.util.HashMap;
      import java.util.Map; /**
      * Constant for 各个列名称的java类,方便我们后期对数据表的CUD操作
      *
      * @author <a href="mailto:magicianisaac@gmail.com">Isaac.Zhang | 若初</a>
      */
      public class Constant { private static final String DATABASE_NAME = "advertisement"; public static class AD_PLAN_TABLE_INFO { public static final String TABLE_NAME = "ad_plan"; public static final String COLUMN_PLAN_ID = "plan_id";
      public static final String COLUMN_USER_ID = "user_id";
      public static final String COLUMN_PLAN_STATUS = "plan_status";
      public static final String COLUMN_START_DATE = "start_date";
      public static final String COLUMN_END_DATE = "end_date";
      } public static class AD_CREATIVE_TABLE_INFO { public static final String TABLE_NAME = "ad_creative"; public static final String COLUMN_CREATIVE_ID = "creative_id";
      public static final String COLUMN_TYPE = "type";
      public static final String COLUMN_MATERIAL_TYPE = "material_type";
      public static final String COLUMN_HEIGHT = "height";
      public static final String COLUMN_WIDTH = "width";
      public static final String COLUMN_AUDIT_STATUS = "audit_status";
      public static final String COLUMN_URL = "url";
      } public static class AD_UNIT_TABLE_INFO { public static final String TABLE_NAME = "ad_unit"; public static final String COLUMN_UNIT_ID = "unit_id";
      public static final String COLUMN_UNIT_STATUS = "unit_status";
      public static final String COLUNN_POSITION_TYPE = "position_type";
      public static final String COLUNN_PLAN_ID = "plan_id";
      } public static class RELATIONSHIP_CREATIVE_UNIT_TABLE_INFO { public static final String TABLE_NAME = "relationship_creative_unit"; public static final String COLUMN_CREATIVE_ID = "creative_id";
      public static final String COLUMN_UNIT_ID = "unit_id";
      } public static class AD_UNIT_DISTRICT_TABLE_INFO { public static final String TABLE_NAME = "ad_unit_district"; public static final String COLUMN_UNIT_ID = "unit_id";
      public static final String COLUMN_PROVINCE = "province";
      public static final String COLUMN_CITY = "city";
      } public static class AD_UNIT_KEYWORD_TABLE_INFO { public static final String TABLE_NAME = "ad_unit_keyword"; public static final String COLUMN_UNIT_ID = "unit_id";
      public static final String COLUMN_KEYWORD = "keyword";
      } public static class AD_UNIT_HOBBY_TABLE_INFO { public static final String TABLE_NAME = "ad_unit_hobby"; public static final String COLUMN_UNIT_ID = "unit_id";
      public static final String COLUMN_HOBBY_TAG = "hobby_tag";
      } //key -> 表名
      //value -> 数据库名
      public static Map<String, String> table2db; static {
      table2db = new HashMap<>();
      table2db.put(AD_PLAN_TABLE_INFO.TABLE_NAME, DATABASE_NAME);
      table2db.put(AD_CREATIVE_TABLE_INFO.TABLE_NAME, DATABASE_NAME);
      table2db.put(AD_UNIT_TABLE_INFO.TABLE_NAME, DATABASE_NAME);
      table2db.put(RELATIONSHIP_CREATIVE_UNIT_TABLE_INFO.TABLE_NAME, DATABASE_NAME);
      table2db.put(AD_UNIT_DISTRICT_TABLE_INFO.TABLE_NAME, DATABASE_NAME);
      table2db.put(AD_UNIT_HOBBY_TABLE_INFO.TABLE_NAME, DATABASE_NAME);
      table2db.put(AD_UNIT_KEYWORD_TABLE_INFO.TABLE_NAME, DATABASE_NAME);
      }
      }