如何将整数转换为整数?

How to convert Integer to int?(如何将整数转换为整数?)

问题描述

我正在开发一个 Web 应用程序，在该应用程序中，数据将在客户端和客户端之间传输.服务器端.

I am working on a web application in which data will be transfer between client & server side.

我已经知道 JavaScript int != Java int.因为，Java int 不能为空，对.现在这是我面临的问题.

I already know that JavaScript int != Java int. Because, Java int cannot be null, right. Now this is the problem I am facing.

我将我的 Java int 变量更改为 Integer.

I changed my Java int variables into Integer.

public void aouEmployee(Employee employee) throws SQLException, ClassNotFoundException
{
   Integer tempID = employee.getId();
   String tname = employee.getName();
   Integer tage = employee.getAge();
   String tdept = employee.getDept();
   PreparedStatement pstmt;
   Class.forName("com.mysql.jdbc.Driver");
   String url ="jdbc:mysql://localhost:3306/general";
   java.sql.Connection con = DriverManager.getConnection(url,"root", "1234");
   System.out.println("URL: " + url);
   System.out.println("Connection: " + con);
   pstmt = (PreparedStatement) con.prepareStatement("REPLACE INTO PERSON SET ID=?, NAME=?, AGE=?, DEPT=?");
   pstmt.setInt(1, tempID);
   pstmt.setString(2, tname);
   pstmt.setInt(3, tage);
   pstmt.setString(4, tdept);
   pstmt.executeUpdate();
 }

我的问题在这里:

pstmt.setInt(1, tempID);

pstmt.setInt(3, tage);

我不能在这里使用整数变量.我试过 intgerObject.intValue();但它使事情变得更加复杂.我们还有其他转换方法或转换技术吗?

I cant use the Integer variables here. I tried with intgerObject.intValue(); But it makes things more complex. Do we have any other conversion methods or conversion techniques?

任何修复都会更好.

推荐答案

正如已经在别处写的:

• 对于 Java 1.5 及更高版本，您(几乎)不需要做任何事情，它由编译器完成.
• 对于 Java 1.4 及之前版本，使用 Integer.intValue() 将 Integer 转换为 int.

• For Java 1.5 and later you don't need to do (almost) anything, it's done by the compiler.
• For Java 1.4 and before, use Integer.intValue() to convert from Integer to int.

但是正如您所写，Integer 可以为空，因此在尝试转换为 int 之前检查一下是明智的(否则可能会遇到 NullPointerException).

pstmt.setInt(1, (tempID != null ? tempID : 0));  // Java 1.5 or later

pstmt.setInt(1, (tempID != null ? tempID.intValue() : 0));  // any version, no autoboxing