关于数组的问题，在线等！

Question

<%@ page contentType="text/html;charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<%@ page import="school.oper.oper" %>
<%
oper oper = new oper();
int count=oper.getBookCount();
String mc;
String book[] = new String[count];
ResultSet rs=oper.getBookType();
while(rs.next())
{
mc=rs.getString("type_mc");
book[book.length]=mc;
}
for(int j=0;j<book.length;j++)
{
out.println("book["+j+"]"+book[j]+"<br>");
}
rs.close();
oper.closeConnect();
%>

Answer 1

book[i]=rs.getString("type_mc");;
怎么两个分号?

Answer 2

<%@ page contentType="text/html;charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<%@ page import="school.oper.oper" %>
<%
oper oper = new oper();
int count=oper.getBookCount();
String mc;
String book[] = new String[count];
ResultSet rs=oper.getBookType();
int i=0;
while(rs.next())
{
mc=rs.getString("type_mc");
book[i]=mc;
i++;
}
for(int j=0;j<book.length;j++)
{
out.println("book["+j+"]"+book[j]+"<br>");
}
rs.close();
oper.closeConnect();
%>

Answer 3

两个分号没关系while(rs.next())
{

for(int i=0;i<book.length;i++)
{
book[i]=rs.getString("type_mc"); //数组每个值都设为一样了
}

}
改为
    for (int i = 0; rs.next() && (i < book.length); i++) {
      book[i] = rs.getString("type_mc");
    }

Answer 4

while(rs.next())
{
mc=rs.getString("type_mc");
for(int i=0;i<book.length;i++)
{
                  
book[i]=mc;
}
}改为
for(int i=0;i<book.length;i++)
{
                  if(rs.next())
book[i]=rs.getString("type_mc");
}