MyBatisSystemException: Parameter 'reqNums' Not Found

The exception message 'org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.binding.BindingException: Parameter 'reqNums' not found. Available parameters are [outpatNum, arg1, param1, param2]' indicates that there's a mismatch between the parameter you're trying to use ('reqNums') and the parameters actually available to the MyBatis mapper. This is usually caused by a typo in the parameter name or a discrepancy between your code and the SQL mapping.

To resolve this, follow these steps:

1. Verify Parameter Name: Double-check the parameter name in your Java method and the corresponding parameter in your SQL statement. Ensure they are identical. Case sensitivity might also be a factor, so pay attention to capitalization.

2. Inspect Method Signature: Examine the method signature in your Mapper interface. Make sure the parameter 'reqNums' is correctly defined and matches the type you're using.

3. Review SQL Mapping: Review your SQL statement. Confirm that the parameter placeholder (e.g., #{reqNums}) matches the parameter name used in your method signature and the actual value you're passing.

4. Check for Mismatched Types: Ensure that the data type of the parameter in your method matches the data type expected by the SQL statement. Mismatched types can lead to binding issues.

5. Consider Parameter Mapping: If you are using complex objects as parameters, ensure they are correctly mapped to the SQL statement using the appropriate MyBatis annotations or XML configuration.

By carefully reviewing these steps, you should be able to identify and correct the issue causing the 'Parameter 'reqNums' not found' exception.