mybatis 插件: 打印 sql 及其执行时间实现方法

@Intercepts({@Signature(type = StatementHandler.class, method = "query", args = {Statement.class, ResultHandler.class}), @Signature(type = StatementHandler.class, method = "update", args = {Statement.class}), @Signature(type = StatementHandler.class, method = "batch", args = { Statement.class })})public class SqlCostInterceptor implements Interceptor {  @Override public Object intercept(Invocation invocation) throws Throwable {  Object target = invocation.getTarget();     long startTime = System.currentTimeMillis();  StatementHandler statementHandler = (StatementHandler)target;  try {   return invocation.proceed();  } finally {   long endTime = System.currentTimeMillis();   long sqlCost = endTime - startTime;       BoundSql boundSql = statementHandler.getBoundSql();   String sql = boundSql.getSql();   Object parameterObject = boundSql.getParameterObject();   List<ParameterMapping> parameterMappingList = boundSql.getParameterMappings();       // 格式化Sql语句，去除换行符，替换参数   sql = formatSql(sql, parameterObject, parameterMappingList);       System.out.println("SQL：[" + sql + "]执行耗时[" + sqlCost + "ms]");  } }  @Override public Object plugin(Object target) {  return Plugin.wrap(target, this); }  @Override public void setProperties(Properties properties) {    }   @SuppressWarnings("unchecked") private String formatSql(String sql, Object parameterObject, List<ParameterMapping> parameterMappingList) {  // 输入sql字符串空判断  if (sql == null || sql.length() == 0) {   return "";  }     // 美化sql  sql = beautifySql(sql);     // 不传参数的场景，直接把Sql美化一下返回出去  if (parameterObject == null || parameterMappingList == null || parameterMappingList.size() == 0) {   return sql;  }     // 定义一个没有替换过占位符的sql，用于出异常时返回  String sqlWithoutReplacePlaceholder = sql;     try {   if (parameterMappingList != null) {    Class<?> parameterObjectClass = parameterObject.getClass();     // 如果参数是StrictMap且Value类型为Collection，获取key="list"的属性，这里主要是为了处理<foreach>循环时传入List这种参数的占位符替换    // 例如select * from xxx where id in <foreach collection="list">...</foreach>    if (isStrictMap(parameterObjectClass)) {     StrictMap<Collection<?>> strictMap = (StrictMap<Collection<?>>)parameterObject;           if (isList(strictMap.get("list").getClass())) {      sql = handleListParameter(sql, strictMap.get("list"));     }    } else if (isMap(parameterObjectClass)) {     // 如果参数是Map则直接强转，通过map.get(key)方法获取真正的属性值     // 这里主要是为了处理<insert>、<delete>、<update>、<select>时传入parameterType为map的场景     Map<?, ?> paramMap = (Map<?, ?>) parameterObject;     sql = handleMapParameter(sql, paramMap, parameterMappingList);    } else {     // 通用场景，比如传的是一个自定义的对象或者八种基本数据类型之一或者String     sql = handleCommonParameter(sql, parameterMappingList, parameterObjectClass, parameterObject);    }   }  } catch (Exception e) {   // 占位符替换过程中出现异常，则返回没有替换过占位符但是格式美化过的sql，这样至少保证sql语句比BoundSql中的sql更好看   return sqlWithoutReplacePlaceholder;  }     return sql; }    private String beautifySql(String sql) {  sql = sql.replace("\n", "").replace("\t", "").replace(" ", " ").replace("( ", "(").replace(" )", ")").replace(" ,", ",");     return sql; }    private String handleListParameter(String sql, Collection<?> col) {  if (col != null && col.size() != 0) {   for (Object obj : col) {    String value = null;    Class<?> objClass = obj.getClass();         // 只处理基本数据类型、基本数据类型的包装类、String这三种    // 如果是复合类型也是可以的，不过复杂点且这种场景较少，写代码的时候要判断一下要拿到的是复合类型中的哪个属性    if (isPrimitiveOrPrimitiveWrapper(objClass)) {     value = obj.toString();    } else if (objClass.isAssignableFrom(String.class)) {     value = "\"" + obj.toString() + "\"";     }         sql = sql.replaceFirst("\\?", value);   }  }     return sql; }    private String handleMapParameter(String sql, Map<?, ?> paramMap, List<ParameterMapping> parameterMappingList) {  for (ParameterMapping parameterMapping : parameterMappingList) {   Object propertyName = parameterMapping.getProperty();   Object propertyValue = paramMap.get(propertyName);   if (propertyValue != null) {    if (propertyValue.getClass().isAssignableFrom(String.class)) {     propertyValue = "\"" + propertyValue + "\"";    }     sql = sql.replaceFirst("\\?", propertyValue.toString());   }  }     return sql; }    private String handleCommonParameter(String sql, List<ParameterMapping> parameterMappingList, Class<?> parameterObjectClass,    Object parameterObject) throws Exception {  for (ParameterMapping parameterMapping : parameterMappingList) {   String propertyValue = null;   // 基本数据类型或者基本数据类型的包装类，直接toString即可获取其真正的参数值，其余直接取paramterMapping中的property属性即可   if (isPrimitiveOrPrimitiveWrapper(parameterObjectClass)) {    propertyValue = parameterObject.toString();   } else {    String propertyName = parameterMapping.getProperty();         Field field = parameterObjectClass.getDeclaredField(propertyName);    // 要获取Field中的属性值，这里必须将私有属性的accessible设置为true    field.setAccessible(true);    propertyValue = String.valueOf(field.get(parameterObject));    if (parameterMapping.getJavaType().isAssignableFrom(String.class)) {     propertyValue = "\"" + propertyValue + "\"";    }   }    sql = sql.replaceFirst("\\?", propertyValue);  }     return sql; }    private boolean isPrimitiveOrPrimitiveWrapper(Class<?> parameterObjectClass) {  return parameterObjectClass.isPrimitive() ||     (parameterObjectClass.isAssignableFrom(Byte.class) || parameterObjectClass.isAssignableFrom(Short.class) ||      parameterObjectClass.isAssignableFrom(Integer.class) || parameterObjectClass.isAssignableFrom(Long.class) ||      parameterObjectClass.isAssignableFrom(Double.class) || parameterObjectClass.isAssignableFrom(Float.class) ||      parameterObjectClass.isAssignableFrom(Character.class) || parameterObjectClass.isAssignableFrom(Boolean.class)); }    private boolean isStrictMap(Class<?> parameterObjectClass) {  return parameterObjectClass.isAssignableFrom(StrictMap.class); }    private boolean isList(Class<?> clazz) {  Class<?>[] interfaceClasses = clazz.getInterfaces();  for (Class<?> interfaceClass : interfaceClasses) {   if (interfaceClass.isAssignableFrom(List.class)) {    return true;   }  }     return false; }    private boolean isMap(Class<?> parameterObjectClass) {  Class<?>[] interfaceClasses = parameterObjectClass.getInterfaces();  for (Class<?> interfaceClass : interfaceClasses) {   if (interfaceClass.isAssignableFrom(Map.class)) {    return true;   }  }     return false; }  }