我在这里遇到问题,我试图根据个人的年龄来计算一个人的月,周,日,小时,分钟和秒的数量。我使用HTML表单来获取数据(名称和年龄)并将其发送到servlet以计算上述结果。问题是,当用户提供29岁或更低的年龄时,结果似乎是准确的,但是当用户输入大于70或更大的值时,它会在秒数内给出错误的负值。这是我的servlet代码:
package package1;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class Servlet_Post_Example extends HttpServlet
{
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
String name = "";
String $age = "";
try
{
name = request.getParameter("name");
$age = request.getParameter("age");
int age = Integer.parseInt($age);
int months = age * 12;
int weeks = age * 52;
int days = age * 365;
int hours = 24 * 365 * age;
int minutes = 60 * 24 * 365 * age;
int seconds = 60 * minutes;
out.println("<html>");
out.println(" <head>");
out.println(" <title>Servlet Get Response</title>");
out.println(" </head>");
out.println(" <body bgcolor=\"#AAFFAA\">");
out.println(" <h1>"+name+" you are approximately "+months+" months old, "+weeks+" weeks old, "+days+" days old, "+hours+" hours old, "+minutes+" minutes old and "+seconds+" seconds old!</h1>");
out.println(" <a href=\"index.html\">Click here</a> to go back to the index page.");
out.println(" </body>");
out.println("</html>");
}
catch(NumberFormatException xcp)
{
out.println("<html>");
out.println(" <head>");
out.println(" <title>Servlet Get Response</title>");
out.println(" </head>");
out.println(" <body bgcolor=\"#AAAAAA\">");
out.println(" <h1 style=\"color: red\">There was an error! You must type the a valid integer for your age! You entered "+$age+"</h1>");
out.println(" <a href=\"index.html\">Click here</a> to go back to the index page.");
out.println(" </body>");
out.println("</html>");
//xcp.printStackTrace(out);
}
finally
{
out.close();
}
}
}
该网站已托管here.,请查看谢谢。
答案 0 :(得分:3)
此行int minutes = 60 * 24 * 365 * age;
和int seconds = 60 * minutes;
可能会超出Integer.MAX_VALUE
的限制。将分钟和秒声明为long
:
long minutes = 60L * 24 * 365 * age;// Add L for long
long seconds = 60 * minutes;
答案 1 :(得分:0)
您需要将分钟和秒的类型更改为long。那它应该工作正常。因为任何大于2 ^ 31-1的int值都会导致溢出,并且由于此溢出是静默的,所以您得到负值。