Swagger2异常 java.lang.NumberFormatException: For input string: ""

问题
在访问swagger首页时报错：

java.lang.NumberFormatException: For input string: ""
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    at java.lang.Long.parseLong(Long.java:601)
    at java.lang.Long.valueOf(Long.java:803)
    at io.swagger.models.parameters.AbstractSerializableParameter.getExample(AbstractSerializableParameter.java:412)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:687)
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:719)

报错的版本是2.9.2，2.7.0的版本是不报错的，2.8的版本也不会
我的依赖是这样的

       <dependency>
         <groupId>io.springfox</groupId>
         <artifactId>springfox-swagger2</artifactId>
<!--         <version>2.7.0</version>-->
         <version>2.9.2</version>
      </dependency>
      <dependency>
         <groupId>io.springfox</groupId>
         <artifactId>springfox-swagger-ui</artifactId>
<!--         <version>2.7.0</version>-->
         <version>2.9.2</version>
      </dependency>

原因
AbstractSerializableParameter.class 

默认值为""，如果没有@ApiModelProperty(value = "id",example = "123")设置example值，则会出现上面异常

解决
修改swagger-models版本，1.5.21进行了修复

pom.xml文件修改为

<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger2</artifactId>
    <version>2.9.2</version>
    <exclusions>
        <exclusion>
            <groupId>io.swagger</groupId>
            <artifactId>swagger-annotations</artifactId>
        </exclusion>
        <exclusion>
            <groupId>io.swagger</groupId>
            <artifactId>swagger-models</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger-ui</artifactId>
    <version>2.9.2</version>
</dependency>
<dependency>
    <groupId>io.swagger</groupId>
    <artifactId>swagger-annotations</artifactId>
    <version>1.5.21</version>
</dependency>
<dependency>
    <groupId>io.swagger</groupId>
    <artifactId>swagger-models</artifactId>
    <version>1.5.21</version>
</dependency>

或者是选择降低版本，使用2.7或者2.8