mybatis利用插件实现分表

如标题，这次的分表规则比较？？，部分用户相关表按产品维度划分，例如:user_1,user_2（1，2是产品id，新加一个产品就要新增一整套表…）研究了一波sharing-jdbc(后面改成了sharding-sphere)不太合适，也有种杀鸡牛刀的感觉。不想手写SQL太麻烦，后面说不好表要改动，虽然有生成工具(不灵活)，所以选择了Mybatis-plus这个兄弟，借鉴他的分页等各种插件决定自己实现一个分表插件，把需要分表的表在配置中维护，利用jsqlparser解析sql重写sql语句，废话不多说上代码/分表插件@author chonglou@date 2019/2/2117:04/@Intercepts({@Signature(type = StatementHandler.class, method = “prepare”, args = {Connection.class, Integer.class})})public class ShardInterceptor implements Interceptor, ShardAgent {private final ShardProperties shardProperties;public ShardInterceptor(ShardProperties shardProperties) { this.shardProperties = shardProperties;}public static final CCJSqlParserManager parser = new CCJSqlParserManager();@Overridepublic Object intercept(Invocation invocation) throws Throwable { StatementHandler statementHandler = (StatementHandler) realTarget(invocation.getTarget()); MetaObject metaObject = SystemMetaObject.forObject(statementHandler); MappedStatement mappedStatement = (MappedStatement) metaObject.getValue(“delegate.mappedStatement”); if (!shardProperties.isException(mappedStatement.getId())) { if (SqlCommandType.INSERT.equals(mappedStatement.getSqlCommandType()) || SqlCommandType.SELECT.equals(mappedStatement.getSqlCommandType()) || SqlCommandType.UPDATE.equals(mappedStatement.getSqlCommandType()) || SqlCommandType.DELETE.equals(mappedStatement.getSqlCommandType())) { String sql = statementHandler.getBoundSql().getSql(); Statement statement = parser.parse(new StringReader(sql)); if (statement instanceof Select) { Select select = (Select) statement; TableNameModifier modifier = new TableNameModifier(this); select.getSelectBody().accept(modifier); } else if (statement instanceof Update) { Update update = (Update) statement; List<Table> list = update.getTables(); for (Table t : list) { parserTable(t, true); } } else if (statement instanceof Delete) { Delete delete = (Delete) statement; parserTable(delete.getTable(), true); List<Table> list = delete.getTables(); for (Table t : list) { parserTable(t, true); } } else if (statement instanceof Insert) { Insert insert = (Insert) statement; parserTable(insert.getTable(), false); } StatementDeParser deParser = new StatementDeParser(new StringBuilder()); statement.accept(deParser); sql = deParser.getBuffer().toString(); ReflectionUtils.setFieldValue(statementHandler.getBoundSql(), “sql”, sql); } } return invocation.proceed();}private Object realTarget(Object target) { if (Proxy.isProxyClass(target.getClass())) { MetaObject metaObject = SystemMetaObject.forObject(target); return realTarget(metaObject.getValue(“h.target”)); } else { return target; }}/* * 覆盖表名设置别名 * * @param table * @return /private Table parserTable(Table table, boolean alias) { if (null != table) { if (alias) { table.setAlias(new Alias(table.getName())); } table.setName(getTargetTableName(table.getName())); } return table;}@Overridepublic Object plugin(Object target) { if (target instanceof StatementHandler) { return Plugin.wrap(target, this); } return target;}@Overridepublic void setProperties(Properties properties) {}@Overridepublic String getTargetTableName(String tableName) { if (shardProperties.isAgentTable(tableName)) { return ShardUtil.getTargetTableName(tableName); } return tableName;}}/**@author chonglou@date 2019/2/2218:24/public interface ShardAgent {String getTargetTableName(String name);}/工具@author chonglou@date 2019/2/2514:11/public class ShardUtil {private final static String KEY_GENERATOR = “keyGenerator”;public static void setKeyGenerator(Object keyGenerator) { HttpServletRequest request = SpringContextHolder.getRequest(); request.setAttribute(KEY_GENERATOR, keyGenerator);}public static String getTargetTableName(String tableName) { HttpServletRequest request = SpringContextHolder.getRequest(); Object productId = request.getAttribute(KEY_GENERATOR); if (null == productId) { throw new RuntimeException(“keyGenerator is null.”); } return tableName.concat("_").concat(productId.toString());}}/Spring的ApplicationContext的持有者,可以用静态方法的方式获取spring容器中的bean,Request 以及 Session@author chonglou/@Componentpublic class SpringContextHolder implements ApplicationContextAware {private static ApplicationContext applicationContext;@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException { SpringContextHolder.applicationContext = applicationContext;}public static ApplicationContext getApplicationContext() { assertApplicationContext(); return applicationContext;}public static <T> T getBean(String beanName) { assertApplicationContext(); return (T) applicationContext.getBean(beanName);}public static <T> T getBean(Class<T> requiredType) { assertApplicationContext(); return applicationContext.getBean(requiredType);}private static void assertApplicationContext() { if (null == SpringContextHolder.applicationContext) { throw new RuntimeException(“applicationContext属性为null,请检查是否注入了SpringContextHolder!”); }}/ * 获取当前请求的Request对象 * * @return HttpServletRequest /public static HttpServletRequest getRequest() { ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes(); return requestAttributes.getRequest();}/* * 获取当前请求的session对象 * * @return HttpSession /public static HttpSession getSession() { return getRequest().getSession();}}/查询语句修改@author chonglou@date 2019/2/2211:31/public class TableNameModifier extends SelectDeParser {private ShardAgent shardAgent;TableNameModifier(ShardAgent shardAgent) { super(); this.shardAgent = shardAgent;}@Overridepublic void visit(Table tableName) { StringBuilder buffer = new StringBuilder(); tableName.setName(shardAgent.getTargetTableName(tableName.getName())); buffer.append(tableName.getFullyQualifiedName()); Alias alias = tableName.getAlias(); if (alias == null) { alias = new Alias(tableName.getName()); } buffer.append(alias); Pivot pivot = tableName.getPivot(); if (pivot != null) { pivot.accept(this); } MySQLIndexHint indexHint = tableName.getIndexHint(); if (indexHint != null) { buffer.append(indexHint); }}}/*@author chonglou@date 2019/2/2215:34/@ConfigurationProperties(prefix = “shard.config”)public class ShardProperties {private List<String> exceptionMapperId;private List<String> agentTables;public boolean isException(String mapperId) { return null != exceptionMapperId && exceptionMapperId.contains(mapperId);}public boolean isAgentTable(String tableName) { return null != agentTables && agentTables.contains(tableName);}public List<String> getExceptionMapperId() { return exceptionMapperId;}public void setExceptionMapperId(List<String> exceptionMapperId) { this.exceptionMapperId = exceptionMapperId;}public List<String> getAgentTables() { return agentTables;}public void setAgentTables(List<String> agentTables) { this.agentTables = agentTables;}}