MyBatis 拦截器（二）

核心代码

@Slf4j
@Component
@Intercepts(value = {
        @Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class}),
        @Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})
})
public class SqlInterceptor implements Interceptor {
    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        Object returnValue = null;
        try {
            MappedStatement mappedStatement = (MappedStatement) invocation.getArgs()[0];
            String sqlId = mappedStatement.getId();
            if(sqlId.contains("History") || sqlId.contains("Tmp")){
                return invocation.proceed();
            }
            Object parameter = null;
            if (invocation.getArgs().length > 1) {
                parameter = invocation.getArgs()[1];
            }
            BoundSql boundSql = mappedStatement.getBoundSql(parameter);
            Configuration configuration = mappedStatement.getConfiguration();

            long start = System.currentTimeMillis();
            returnValue = invocation.proceed();
            long end = System.currentTimeMillis();
            long time = (end - start);
            String sql = getSql(configuration, boundSql, sqlId, time);
            log.info("SQL 监控: {}", sql);
        } catch (Exception e) {
            log.error("SQL拦截器异常");
            return invocation.proceed();
        }
        return returnValue;
    }

    @Override
    public Object plugin(Object target) {
        log.info("Interceptor::plugin#target={}", target);
        if(target instanceof Executor){
            return Plugin.wrap(target, this);
        }
        return target;
    }

    @Override
    public void setProperties(Properties properties) {

    }

    public static String getSql(Configuration configuration, BoundSql boundSql, String sqlId, long time) {
        String sql = showSql(configuration, boundSql);
        StringBuilder sb = new StringBuilder(100);
        sb.append("[sqlId]: ").append(sqlId);
        sb.append(" [SQL耗时: ").append(time).append(" 毫秒]");
        sb.append(" [SQL]:").append(sql);
        log.debug(sb.toString());
        return sb.toString();
    }

    public static String showSql(Configuration configuration, BoundSql boundSql) {
        Object parameterObject = boundSql.getParameterObject();
        List<ParameterMapping> parameterMappings = boundSql.getParameterMappings();
        String sql = boundSql.getSql().replaceAll("[\\s]+", " ");
        if (parameterMappings.size() > 0 && parameterObject != null) {
            TypeHandlerRegistry typeHandlerRegistry = configuration.getTypeHandlerRegistry();
            if (typeHandlerRegistry.hasTypeHandler(parameterObject.getClass())) {
                sql = sql.replaceFirst("\\?", getParameterValue(parameterObject));
            } else {
                MetaObject metaObject = configuration.newMetaObject(parameterObject);
                for (ParameterMapping parameterMapping : parameterMappings) {
                    String propertyName = parameterMapping.getProperty();
                    if (metaObject.hasGetter(propertyName)) {
                        Object obj = metaObject.getValue(propertyName);
                        sql = sql.replaceFirst("\\?", getParameterValue(obj));
                    } else if (boundSql.hasAdditionalParameter(propertyName)) {
                        Object obj = boundSql.getAdditionalParameter(propertyName);
                        sql = sql.replaceFirst("\\?", getParameterValue(obj));
                    }
                }
            }
        }
        return sql;
    }

    private static String getParameterValue(Object obj) {
        String value = null;
        if (obj instanceof String) {
            value = "'" + obj + "'";
            value = value.replaceAll("\\\\", "\\\\\\\\");
            value = value.replaceAll("\\$", "\\\\\\$");
        } else if (obj instanceof Date) {
            DateFormat formatter = DateFormat.getDateTimeInstance(DateFormat.DEFAULT, DateFormat.DEFAULT, Locale.CHINA);
            value = "'" + formatter.format(obj) + "'";
        } else {
            if (obj != null) {
                value = obj.toString();
            } else {
                value = "";
            }
        }
        return value;
    }
}

拦截器

• plugin方法，每种代理类型都会调用该方法

  • plugin#target=org.apache.ibatis.executor.CachingExecutor@aadddeb
  • plugin#target=org.apache.ibatis.scripting.defaults.DefaultParameterHandler@1bb554b0
  • plugin#target=org.apache.ibatis.executor.resultset.DefaultResultSetHandler@6824a9b0
  • plugin#target=org.apache.ibatis.executor.statement.RoutingStatementHandler@560f1f4b

• @Intercepts注解指定需要创建代理的类型，会为该类型创建代理，而后会执行interceptor方法

  @Intercepts(value = {
          @Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class}),
          @Signature(type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class})
  })
  

  • type：拦截类型
  • method：拦截类型接口中定义的方法
  • args：拦截类型接口中定义的方法 的 参数，method + args才能定位一个方法，可能会有多个重载的同名方法