Java 访问 Kylin 总结

这次开发功能是OEM统计报表。统计报表的数据由大数据平台部的同事收集，数据的展示由我们部门开发。

大数据那边使用 Kylin 分布式分析引擎（kylin官方文档）。

Kylin 虽比较偏向大数据相关，但最终大佬们决定把访问 Kylin 的 Dubbo 接口也由我们开发，比较坑。

解决方案一：Mybatis

首先我们搭建一个 shop-mod-bigdata (+ shop-mod-bigdata-interface) 模块用于访问 Kylin，暴露 Dubbo 服务。

Kylin 官方文档提供了 JDBC 的方式访问Kylin。

为了长期考虑，是否可以用上连接池？

Kylin 有提供 JDBC 的方式访问，那就应该会遵循 JDBC 的规范，

参考 Mysql 的连接池配置进行配置

<!-- Kylin 数据源（OEM） -->
    <bean id="kylinOemDataSource" class="org.apache.tomcat.jdbc.pool.DataSource"
		destroy-method="close">
		<property name="driverClassName" value="${ds.kylin.jdbc.Driver}" />
		<property name="url" value="${ds.kylin.oem.jdbc.url}" />
		<property name="username" value="${ds.kylin.oem.jdbc.username}" />
		<property name="password" value="${ds.kylin.oem.jdbc.password}" />
		
		<!-- 连接池配置 -->
		<property name="testWhileIdle" value="${ds.kylin.testWhileIdle}" />
		<property name="testOnBorrow" value="${ds.kylin.testOnBorrow}" />
		<property name="testOnReturn" value="${ds.kylin.testOnReturn}" />
		<property name="validationQuery" value="${ds.kylin.validationQuery}" />
		<property name="validationInterval" value="${ds.kylin.validationInterval}" />
		<property name="timeBetweenEvictionRunsMillis" value="${ds.kylin.timeBetweenEvictionRunsMillis}" />
		<property name="maxActive" value="${ds.kylin.maxActive}" />
		<property name="maxIdle" value="${ds.kylin.maxIdle}" />
		<property name="minIdle" value="${ds.kylin.minIdle}" />
		<property name="maxWait" value="${ds.kylin.maxWait}" />
		<property name="initialSize" value="${ds.kylin.initialSize}" />
		<property name="removeAbandonedTimeout" value="${ds.kylin.removeAbandonedTimeout}" />
		<property name="removeAbandoned" value="${ds.kylin.removeAbandoned}" />
		<property name="logAbandoned" value="${ds.kylin.logAbandoned}" />
		<property name="minEvictableIdleTimeMillis" value="${ds.kylin.minEvictableIdleTimeMillis}" />
		<property name="jmxEnabled" value="${ds.kylin.jmxEnabled}" />
		<property name="jdbcInterceptors" value="${ds.kylin.jdbcInterceptors}" />
	</bean>

加上连接池配置后，下面就要验证和测试了。

1：调试，跟源码。

2：为便于观察运行细节是否正常，修改 log4j 日志配置

log4j.logger.org.apache.tomcat.jdbc=DEBUG
log4j.logger.org.springframework.jdbc=DEBUG
log4j.logger.org.apache.kylin.jdbc=DEBUG
log4j.logger.org.apache.ibatis=DEBUG
log4j.logger.org.mybatis.spring=DEBUG

3：测试有没有内存泄漏，长时间运行时是否有问题：CPU 是否异常，线程数是否异常，连接池是否异常，JVM垃圾回收是否异常，

刚好用用学到的 JVM 相关的东东，这里我就直接使用 JDK 自带的工具（jvisualvm），

入口的话就直接用单元测试+线程池来跑

/**
 * Kylin 访问压测
 * 
 * @author zhangjl
 * @date 2018年3月9日
 */
public class KylinPressureTest extends TestBase {
    @Resource
    private PersonFacade personFacade;

    @Test
    public void pressureTest() {
        ExecutorService threadPool = Executors.newFixedThreadPool(10);
        final AtomicInteger counter = new AtomicInteger();
        final SimpleDateFormat sdf = new SimpleDateFormat("HH:mm:ss");

        // 生成垃圾
        Executors.newScheduledThreadPool(1).scheduleAtFixedRate(new Runnable() {
            @Override
            public void run() {
                int index = generateGarbage();
                LOGGER.info("index={}", index);
            }
        }, 5, 5, TimeUnit.SECONDS);
        
        // 访问 Kylin
        for (int i = 0; i < 10000; i++) {
            LOGGER.info("第" + (i + 1) + "轮开始");

            for (int j = 0; j < 10; j++) {
                threadPool.execute(new Runnable() {
                    @Override
                    public void run() {
                        int currNum = counter.addAndGet(1);
                        
                        try {
                            PageInfo page = new PageInfo();
                            page.setPagination(true);
                            PersonDto condition = new PersonDto();
                            condition.setGender(counter.get());

                            ApiResult<PageResult<PersonDto>> result = personFacade.page(condition, page);
                            LOGGER.info("Kylin访问结果, result={}", result);
                        } catch (Exception e) {
                            LOGGER.error("Kylin访问异常", e);
                        }

                        LOGGER.info("Kylin访问，当前为第{}个，time={}", currNum, sdf.format(new Date()));
                    }
                });
            }

            try {
                Thread.sleep(1L * 60L * 1000L);
            } catch (InterruptedException e) {
                LOGGER.error("线程中断", e);
            }
        }

        // 等待
        waitingUserInputExit();
    }

    private void waitingUserInputExit() {
        Scanner scanner = null;
        try {
            scanner = new Scanner(System.in);
            while (true) {
                String input = scanner.next();
                if ("exit".equals(input)) {
                    break;
                }
            }
        } catch (Exception e) {
            LOGGER.error("输出异常", e);
        } finally {
            if (null != scanner) {
                scanner.close();
            }
        }
    }

    private int generateGarbage() {
        int index = 0;
        byte[] array1 = new byte[100 * 1024 * 1024]; // 100M
        // byte[] array2 = new byte[100 * 1024 * 1024]; // 100M

        array1[index++] = new Byte("1");
        // array2[index++] = new Byte("2");

        return index;
    }
}

修改 VM arguments 参数：

-Xmx1024m -Xms1024m -XX:+PrintGC -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintGCApplicationStoppedTime -XX:+PrintHeapAtGC -Xloggc:mygc.log

结果图：

根据测试结果，连接池应该没什么大问题。

感觉应该可以用 Mybatis ？那就加上 Mybatis 的配置，再试一波。

简单 SQL 验证没问题。

又遇到一个问题：分页。

Mysql分页使用的是：LIMIT ${pageSize}, ${offset}

Kylin分页使用的是：LIMIT ${pageSize} OFFSET ${offset}

好像区别并不大，嗯嗯，完全可以基于以前的 Mysql Dialect 改代码。

<!-- Kylin jdbcTemplate（OEM） -->
	<!-- <bean id="kylinOemJdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
		<property name="dataSource" ref="kylinOemDataSource"></property>
	</bean> -->
	
	<!-- Kylin 不配置统一事务管理器（OEM） -->
	
	<!-- Kylin sqlSessionFactory（OEM） -->
	<bean id="kylinOemSqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
		<property name="dataSource" ref="kylinOemDataSource" />
		<property name="plugins">
			<list>
				<bean class="yunnex.shop.bigdata.common.kylin.KylinMybatisLogInterceptor"></bean>
				<bean class="yunnex.shop.bigdata.common.kylin.KylinMybatisPaginationInterceptor"></bean>
			</list>
		</property>
		<property name="mapperLocations">
			<array>
				<value>classpath*:/yunnex/shop/bigdata/oem/**/*.xml</value>
			</array>
		</property>
	</bean>

	<!-- Kylin MapperScannerConfigurer（OEM） -->
	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
		<property name="basePackage" value="yunnex.shop.bigdata.oem.**.mapper,yunnex.shop.bigdata.oem.**.dao" />
		<property name="sqlSessionFactoryBeanName" value="kylinOemSqlSessionFactory"></property>
	</bean>

/**
 * 分页拦截器
 * 
 * @author zhangjl
 * @date 2018年3月9日
 */
@Intercepts({@Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})})
public class KylinMybatisPaginationInterceptor implements Interceptor {
    private Logger LOGGER = LoggerFactory.getLogger(KylinMybatisPaginationInterceptor.class);

    Dialect dialect = new KylinDialect();

    @Value("${sql.rows.max.return}")
    private Integer rowlimit;

    @SuppressWarnings("unchecked")
    public Object intercept(Invocation invocation) throws Throwable {
        MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0];
        Object parameter = invocation.getArgs()[1];
        BoundSql boundSql = mappedStatement.getBoundSql(parameter);
        String sqlId = mappedStatement.getId();
        String originalSql = boundSql.getSql().trim();
        RowBounds rowBounds = (RowBounds) invocation.getArgs()[2];

        Object parameterObject = boundSql.getParameterObject();
        if (boundSql.getSql() == null || "".equals(boundSql.getSql())) {
            return null;
        }

        // 分页参数--上下文传参
        PageInfo page = null;

        // map传参每次都将currentPage重置,先判读map再判断context
        if (parameterObject instanceof PageInfo) {
            page = (PageInfo) parameterObject;
        } else if (parameterObject instanceof Map) {
            Map<String, Object> map = (Map<String, Object>) parameterObject;
            if (map.containsKey("page")) {
                page = (PageInfo) map.get("page");
            }
        } else if (null != parameterObject) {
            Field pageField = ReflectionUtil.getFieldByFieldName(parameterObject, "page");
            if (pageField != null) {
                page = (PageInfo) ReflectionUtil.getValueByFieldName(parameterObject, "page");
            }
        }

        // 后面用到了context的东东
        if (page != null && page.isPagination() == true) {
            if (page.getPageSize() > rowlimit) {
                LOGGER.warn("[toolarge_pagesize] page size greater than {},#sqlid:{}#,#pagesize:{}#,#sql:{}#", rowlimit, sqlId, page.getPageSize(),
                                originalSql);
                page.setPageSize(rowlimit);
            }

            int totalRows = page.getTotalRows();
            // 得到总记录数
            if (totalRows == 0 && page.isNeedCount()) {
                StringBuilder countSql = new StringBuilder();
                countSql.append(KylinPageHepler.getCountString(originalSql));
                Connection connection = mappedStatement.getConfiguration().getEnvironment().getDataSource().getConnection();
                PreparedStatement countStmt = connection.prepareStatement(countSql.toString());
                BoundSql countBS = new BoundSql(mappedStatement.getConfiguration(), countSql.toString(), boundSql.getParameterMappings(),
                                parameterObject);
                Field metaParamsField = ReflectionUtil.getFieldByFieldName(boundSql, "metaParameters");
                if (metaParamsField != null) {
                    MetaObject mo = (MetaObject) ReflectionUtil.getValueByFieldName(boundSql, "metaParameters");
                    ReflectionUtil.setValueByFieldName(countBS, "metaParameters", mo);
                }
                setParameters(countStmt, mappedStatement, countBS, parameterObject);
                ResultSet rs = countStmt.executeQuery();
                if (rs.next()) {
                    totalRows = rs.getInt(1);
                }
                rs.close();
                countStmt.close();
                connection.close();
            }

            // 分页计算
            page.init(totalRows, page.getPageSize(), page.getCurrentPage());

            if (rowBounds == null || rowBounds == RowBounds.DEFAULT) {
                rowBounds = new RowBounds(page.getPageSize() * (page.getCurrentPage() - 1), page.getPageSize());
            }

            // 分页查询 本地化对象 修改数据库注意修改实现
            String pagesql = dialect.getLimitString(originalSql, rowBounds.getOffset(), rowBounds.getLimit());
            invocation.getArgs()[2] = new RowBounds(RowBounds.NO_ROW_OFFSET, RowBounds.NO_ROW_LIMIT);
            BoundSql newBoundSql = new BoundSql(mappedStatement.getConfiguration(), pagesql, boundSql.getParameterMappings(),
                            boundSql.getParameterObject());
            Field metaParamsField = ReflectionUtil.getFieldByFieldName(boundSql, "metaParameters");
            if (metaParamsField != null) {
                MetaObject mo = (MetaObject) ReflectionUtil.getValueByFieldName(boundSql, "metaParameters");
                ReflectionUtil.setValueByFieldName(newBoundSql, "metaParameters", mo);
            }
            MappedStatement newMs = copyFromMappedStatement(mappedStatement, new BoundSqlSqlSource(newBoundSql));

            invocation.getArgs()[0] = newMs;
        }

        return invocation.proceed();
    }

    public static class BoundSqlSqlSource implements SqlSource {
        BoundSql boundSql;

        public BoundSqlSqlSource(BoundSql boundSql) {
            this.boundSql = boundSql;
        }

        public BoundSql getBoundSql(Object parameterObject) {
            return boundSql;
        }
    }

    public Object plugin(Object arg0) {
        return Plugin.wrap(arg0, this);
    }

    public void setProperties(Properties arg0) {

    }

    /**
     * 对SQL参数(?)设值,参考org.apache.ibatis.executor.parameter.DefaultParameterHandler
     * 
     * @param ps
     * @param mappedStatement
     * @param boundSql
     * @param parameterObject
     * @throws SQLException
     */
    @SuppressWarnings({"rawtypes", "unchecked"})
    private void setParameters(PreparedStatement ps, MappedStatement mappedStatement, BoundSql boundSql, Object parameterObject) throws SQLException {
        ErrorContext.instance().activity("setting parameters").object(mappedStatement.getParameterMap().getId());
        List<ParameterMapping> parameterMappings = boundSql.getParameterMappings();
        if (parameterMappings != null) {
            Configuration configuration = mappedStatement.getConfiguration();
            TypeHandlerRegistry typeHandlerRegistry = configuration.getTypeHandlerRegistry();
            MetaObject metaObject = parameterObject == null ? null : configuration.newMetaObject(parameterObject);
            for (int i = 0; i < parameterMappings.size(); i++) {
                ParameterMapping parameterMapping = parameterMappings.get(i);
                if (parameterMapping.getMode() != ParameterMode.OUT) {
                    Object value;
                    String propertyName = parameterMapping.getProperty();
                    PropertyTokenizer prop = new PropertyTokenizer(propertyName);
                    if (parameterObject == null) {
                        value = null;
                    } else if (typeHandlerRegistry.hasTypeHandler(parameterObject.getClass())) {
                        value = parameterObject;
                    } else if (boundSql.hasAdditionalParameter(propertyName)) {
                        value = boundSql.getAdditionalParameter(propertyName);
                    } else if (propertyName.startsWith(ForEachSqlNode.ITEM_PREFIX) && boundSql.hasAdditionalParameter(prop.getName())) {
                        value = boundSql.getAdditionalParameter(prop.getName());
                        if (value != null) {
                            value = configuration.newMetaObject(value).getValue(propertyName.substring(prop.getName().length()));
                        }
                    } else {
                        value = metaObject == null ? null : metaObject.getValue(propertyName);
                    }
                    TypeHandler typeHandler = parameterMapping.getTypeHandler();
                    if (typeHandler == null) {
                        throw new ExecutorException(
                                        "There was no TypeHandler found for parameter " + propertyName + " of statement " + mappedStatement.getId());
                    }
                    typeHandler.setParameter(ps, i + 1, value, parameterMapping.getJdbcType());
                }
            }
        }
    }

    private MappedStatement copyFromMappedStatement(MappedStatement ms, SqlSource newSqlSource) {
        Builder builder = new MappedStatement.Builder(ms.getConfiguration(), ms.getId(), newSqlSource, ms.getSqlCommandType());
        builder.resource(ms.getResource());
        builder.fetchSize(ms.getFetchSize());
        builder.statementType(ms.getStatementType());
        builder.keyGenerator(ms.getKeyGenerator());
        builder.keyProperty(buildKeyProperty(ms.getKeyProperties()));
        builder.timeout(ms.getTimeout());
        builder.parameterMap(ms.getParameterMap());
        builder.resultMaps(ms.getResultMaps());
        builder.useCache(ms.isUseCache());
        builder.cache(ms.getCache());
        MappedStatement newMs = builder.build();
        return newMs;
    }

    private static String buildKeyProperty(String[] props) {
        if (null != props && props.length > 0) {
            StringBuilder sb = new StringBuilder();
            for (String p : props) {
                sb.append(p).append(",");
            }

            return sb.substring(0, sb.length() - 1);
        }
        return null;
    }
}

　　

/**
 * Kylin Dialect
 * 
 * @author zhangjl
 * @date 2018年3月9日
 */
public class KylinDialect extends Dialect {
    protected static final String SQL_END_DELIMITER = ";";

    public String getLimitString(String sql, boolean hasOffset) {
        return KylinPageHepler.getLimitString(sql, -1, -1);
    }

    @Override
    public String getLimitString(String sql, int offset, int limit) {
        return KylinPageHepler.getLimitString(sql, offset, limit);
    }

    @Override
    public boolean supportsLimit() {
        return true;
    }
}

　　

/**
 * 分页帮助类
 * 
 * @author zhangjl
 * @date 2018年3月9日
 */
public class KylinPageHepler {
    /**
     * 得到查询总数的sql
     */
    public static String getCountString(String querySelect) {
        querySelect = getLineSql(querySelect);
        int orderIndex = getLastOrderInsertPoint(querySelect);

        int formIndex = getAfterFormInsertPoint(querySelect);
        String select = querySelect.substring(0, formIndex);

        // 如果SELECT 中包含 DISTINCT 只能在外层包含COUNT
        if (select.toLowerCase().indexOf("select distinct") != -1 || querySelect.toLowerCase().indexOf("group by") != -1) {
            return new StringBuffer(querySelect.length()).append("select count(1) from (").append(querySelect.substring(0, orderIndex))
                            .append(" ) t").toString();
        } else {
            return new StringBuffer(querySelect.length()).append("select count(1) ").append(querySelect.substring(formIndex, orderIndex))
                            .toString();
        }
    }

    /**
     * 得到最后一个Order By的插入点位置
     * 
     * @return 返回最后一个Order By插入点的位置
     */
    private static int getLastOrderInsertPoint(String querySelect) {
        int orderIndex = querySelect.toLowerCase().lastIndexOf("order by");
        if (orderIndex == -1 || !isBracketCanPartnership(querySelect.substring(orderIndex, querySelect.length()))) {
            throw new RuntimeException("Kylin SQL 分页必须要有Order by 语句!");
        }
        return orderIndex;
    }

    /**
     * 得到分页的SQL
     * 
     * @param offset 偏移量
     * @param limit 位置
     * @return 分页SQL
     */
    public static String getLimitString(String querySelect, int offset, int limit) {
        querySelect = getLineSql(querySelect);

        // String sql = querySelect + " limit " + offset + " ," + limit;
        String sql = querySelect + " limit " + limit + " offset " + offset;
        return sql;
    }

    /**
     * 将SQL语句变成一条语句，并且每个单词的间隔都是1个空格
     * 
     * @param sql SQL语句
     * @return 如果sql是NULL返回空，否则返回转化后的SQL
     */
    private static String getLineSql(String sql) {
        return sql.replaceAll("[
]", " ").replaceAll("\s{2,}", " ");
    }

    /**
     * 得到SQL第一个正确的FROM的的插入点
     */
    private static int getAfterFormInsertPoint(String querySelect) {
        String regex = "\s+FROM\s+";
        Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);
        Matcher matcher = pattern.matcher(querySelect);
        while (matcher.find()) {
            int fromStartIndex = matcher.start(0);
            String text = querySelect.substring(0, fromStartIndex);
            if (isBracketCanPartnership(text)) {
                return fromStartIndex;
            }
        }
        return 0;
    }

    /**
     * 判断括号"()"是否匹配,并不会判断排列顺序是否正确
     * 
     * @param text 要判断的文本
     * @return 如果匹配返回TRUE,否则返回FALSE
     */
    private static boolean isBracketCanPartnership(String text) {
        if (text == null || (getIndexOfCount(text, '(') != getIndexOfCount(text, ')'))) {
            return false;
        }
        return true;
    }

    /**
     * 得到一个字符在另一个字符串中出现的次数
     * 
     * @param text 文本
     * @param ch 字符
     */
    private static int getIndexOfCount(String text, char ch) {
        int count = 0;
        for (int i = 0; i < text.length(); i++) {
            count = (text.charAt(i) == ch) ? count + 1 : count;
        }
        return count;
    }
}

OK，改造完成，又得一波验证跟测试。

解决方案二：Freemarker

解决方案验证没问题，其实有一个更简洁的方案。

1 使用 Freemarker 的渲染功能 ，渲染SQL模板（达到类似 Mybatis 的能力）

2 使用数据库保存 SQL 模板；

3 使用Spring的JdbcTemplate

个人觉得这个方案有比用 Mybatis 更好的优势，SQL 有问题了，用 DML 改下 SQL 模板，都不用改代码了！

下面放出一个 Freemaker 渲染 SQL 模板示例代码：

import java.io.StringWriter;
import java.util.HashMap;
import java.util.Map;

import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import freemarker.cache.StringTemplateLoader;
import freemarker.template.Configuration;
import freemarker.template.Template;

/**
 * Freemarker 测试
 * @author zhangjl
 * @date 2018年3月9日
 */
public class FreemarkerTest {
    private static final Logger LOG = LoggerFactory.getLogger(FreemarkerTest.class);

    @Test
    public void test1() {
        try {
            /**
             * <pre>
             *  SELECT *
                FROM shop
                WHERE 1 = 1
                <#if id??>AND id = ${id?c} </#if>
                <#if order??>ORDER BY ${order} <#if sort??> ${sort} </#if> </#if>
             * </pre>
             */
            String sqlTemplate = "SELECT * FROM shop WHERE 1 = 1 <#if id??>AND id = ${id?c} </#if> <#if order??>ORDER BY ${order} <#if sort??> ${sort} </#if> </#if>";
            String sqlId = "shop.list";
            Map<String, Object> paramMap = new HashMap<>();
            paramMap.put("id", 1L);

            String sql = getSql(sqlId, sqlTemplate, paramMap);
            LOG.info("解析后的SQL={}", sql);
        } catch (Exception e) {
            LOG.error("解析SQL异常", e);
        }
    }

    public String getSql(String sqlId, String sqlTemplate, Map<String, Object> paramMap) throws Exception {
        StringTemplateLoader loader = new StringTemplateLoader();
        loader.putTemplate(sqlId, sqlTemplate);

        Configuration conf = new Configuration();
        conf.setTemplateLoader(loader);

        Template template = conf.getTemplate(sqlId, "utf-8");

        StringWriter writer = new StringWriter();
        template.process(paramMap, writer);
        String sql = writer.toString();
        writer.close();

        return sql;
    }
}