@Pattern Annotation for verifying whether a string complies with a specific regular expression

@Pattern annotation is used to verify that string fields comply with the specified regular expression pattern, ensuring that the data conforms to a specific format, thereby improving accuracy. It can only be used for fields of String type. By adding annotations on the field, specifying regular expression patterns. When the value of the field does not conform to the pattern, an exception will be thrown, improving efficiency and simplifying the verification logic.

@Pattern Annotation: String regular expression verification

Introduction
@Pattern annotation is used to verify that the string field complies with the specified regular expression pattern. It ensures that the values ​​in the field match the specific format, thereby improving the accuracy of the data.

grammar

 <code class="java">@Pattern(regexp = "regex pattern") private String field;</code>

Where the "regexp" property specifies the regular expression pattern.

How to use

1. Add the @Pattern annotation on the target string field.
2. Specify regular expression patterns to define the desired format.
3. When the value of the field does not conform to the pattern, a PatternSyntaxException or IllegalArgumentException exception is thrown.

Example

 <code class="java">@Pattern(regexp = "^[AZ]{2}[0-9]{6}$") private String productCode;</code>

This example ensures that the value of the productCode field complies with the format "AA123456", which starts with two capital letters followed by six numbers.

Type constraints
@Pattern annotations can only be used for fields of type String.

advantage

• Ensure that the data conforms to a specific format and improves accuracy.
• Simplify regular expression verification without manually writing verification logic.
• Verify at compile time to improve efficiency.

Things to note

• Regular expression patterns need to comply with Java regular expression syntax.
• The exception information will contain the specific reason for the violation of the pattern.
• Ensure that the regular expression pattern does not contain special characters (for example, pipeline character |) that may pose a security risk.

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