解决刷新SwaggerUi控制台报错

一、问题描述
在浏览器刷新SwaggerUI的页面，控制台就报错：

java.lang.NumberFormatException: For input string: ""
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) ~[na:1.8.0_291]
    at java.lang.Long.parseLong(Long.java:601) ~[na:1.8.0_291]
    at java.lang.Long.valueOf(Long.java:803) ~[na:1.8.0_291]
    at io.swagger.models.parameters.AbstractSerializableParameter.getExample(AbstractSerializableParameter.java:412) ~[swagger-models-1.5.20.jar:1.5.20]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_291]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_291]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_291]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_291]
    
    ......



2021-08-06 14:43:07.757  WARN 23020 --- [nio-8555-exec-5] i.s.m.p.AbstractSerializableParameter    : Illegal DefaultValue null for parameter type integer


java.lang.NumberFormatException: For input string: ""
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65) ~[na:1.8.0_291]
    at java.lang.Long.parseLong(Long.java:601) ~[na:1.8.0_291]
    at java.lang.Long.valueOf(Long.java:803) ~[na:1.8.0_291]
    at io.swagger.models.parameters.AbstractSerializableParameter.getExample(AbstractSerializableParameter.java:412) ~[swagger-models-1.5.20.jar:1.5.20]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_291]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_291]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_291]
    at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_291]
    
    ......

二、解决办法
在pom中增加依赖

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


<!-- 解决刷新SwaggerUi报错 getExample -->
<dependency>
    <groupId>io.swagger</groupId>
    <artifactId>swagger-annotations</artifactId>
    <version>1.5.22</version>
</dependency>
<!-- 解决刷新SwaggerUi报错 getExample -->
<dependency>
    <groupId>io.swagger</groupId>
    <artifactId>swagger-models</artifactId>
    <version>1.5.22</version>
</dependency>

三、原因
官方代码中存在bug，对于 string 仅判断是否为null 未判断是否为空字符串，导致在将空字串赋值给 int 的时候报错了。