java - 包含撇号字符 U+2019 的字符串在传递给 PreparedStatement 对象时转换为更多字符

Answer 1

If you want to check the length of your String before inserting it in DB, you have to convert it to the charset used by your DB. It can be done with

 new String(string, charset);

for instance

 System.out.println("‘".length()); 
 // displays 1
 System.out.println(new String("‘".getBytes(), "UTF-16").length()); 
 // displays 2
 System.out.println(new String("‘".getBytes(), "ISO-8859-1").length()); 
 // displays 3

see http://docs.oracle.com/javase/1.4.2/docs/api/java/lang/String.html#String%28byte[],%20java.lang.String%29