Using Hibernate Validator and Commons‑Lang3 for Parameter Validation in Spring Boot Controllers

The author, a senior architect, explains why parameter validation should be placed in the controller layer for non‑business rules and in the service layer for business‑related checks.

He introduces Hibernate Validator as a convenient validation framework, showing the Maven dependency and common annotations such as @NotBlank , @Pattern , and @Length .

An example entity is presented: public class DataSetSaveVO { @NotBlank(message = "user uuid is empty") @Pattern(regexp = "^[a-z0-9]+$", message = "user names can only be alphabetic and numeric") @Length(max = 48, message = "user uuid length over 48 byte") private String userUuid; @Pattern(regexp = "^[A-Za-z0-9]+$", message = "data set names can only be letters and Numbers") @Length(max = 48, message = "file name too long") @NotBlank(message = "file name is empty") private String name; @Length(max = 256, message = "data set description length over 256 byte") @NotBlank(message = "data set description is null") private String description; } demonstrating field‑level constraints and custom messages.

In a Spring Boot controller the method is written as: @PostMapping public ResponseVO createDataSet(@Valid @RequestBody DataSetSaveVO dataSetVO) { return ResponseUtil.success(dataSetService.saveDataSet(dataSetVO)); } where @Valid (or @Validated) triggers the defined validations.

The article also introduces Apache Commons‑Lang3, providing its Maven dependency and illustrating typical utility methods such as StringUtils.isEmpty , StringUtils.isBlank , and CollectionUtils.isEmpty with sample test code.

Finally, it notes that when built‑in constraints are insufficient, developers can create custom validation annotations to meet specific requirements.