java异常处理

java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.Integer

解决方案：

Long countLong = 3L;
// java.lang.Number是Integer,Long的父类.
Number num = countLong;
int countInt = num.intValue();
System.out.println(countInt);

 Data truncation: Out of range value adjusted for column 'distance' at row 1

 解决方案:

1. 为 int 类型修改为bigint类型

2. 给该字段设置为null

Failed to parse multipart servlet request; nested exception is java.io.IOException: The temporary upload location

原因：找不到对应路径文件

解决方案：创建异常信息打印出来的路径即可