Bean validation pattern html escaped in generated java code

[apolci]

Description

When generating a java model or api including a "pattern" validation, the pattern is html escaped in the generated java code.
As an example the pattern "[^&]*] translate to the following annotation:
@Pattern("[^&]")

Swagger-codegen version

I'm using 2.2.2 but also the current master present the same problem.

Swagger declaration file content or url

swagger: "2.0"
info:
  version: "1.0"
  title: "Hello World API"
paths:
  /hello/:
    get:
      description: Returns a greeting to the user!
      parameters:
        - name: user
          in: query
          type: string
          pattern: '[^&]*'
          required: true
          description: The name of the user to greet.
      responses:
        200:
          description: Returns the greeting.
          schema:
            type: string

Command line used for generation

java -Dapis -jar swagger-codegen-cli-2.2.2.jar generate -i test.yaml -l spring -c test.conf

Content of test.conf:

{
  "useBeanValidation": true,
  "library": "spring-mvc",
  "generateModelTests": false,
  "generateApis": false,
  "generateSupportingFiles": false,
  "dateLibrary": "java8",
  "interfaceOnly": true
}

Steps to reproduce

1. Run the above command line with provided yaml and conf
2. Search HelloApi.java in the generated sources, it will contain the code @Pattern(regexp="[^&]*")

Tested also in http://editor.swagger.io/

Suggest a Fix

In several mustache templates the text @Pattern(regexp="{{pattern}}") should be replaced with @Pattern(regexp="{{{pattern}}}") to avoid html escaping.

Pull request will follow.

[wing328]

@apolci thanks for reporting the issue and sending a PR to fix it.

I'll also grep the mustache templates to see if there's other occurrence of {{pattern}} and fix accordingly.