Java 在代码上获取 ClassNotFoundException："Class.forName("com.microsoft.sqlserver.jdbc.SqlServerDriver");"
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Getting ClassNotFoundException on code: "Class.forName("com.microsoft.sqlserver.jdbc.SqlServerDriver");"
提问by user2708377
This is my first Javaapplication and I'm completely inexperienced with Javaand NetBeans.
这是我的第一个Java应用程序，我对Java和NetBeans完全没有经验。
I have been trying to connect to sql and get some records for 2 days. The problem is about jdbcdriver, let me explain. I have downloaded sqljdbcdriver and then followed these steps:
我一直在尝试连接到 sql 并获取一些记录 2 天。问题是关于jdbc驱动程序，让我解释一下。我已经下载了sqljdbc驱动程序，然后按照以下步骤操作：
Right-click Project->Select Properties->On the left-hand side click Libraries->Under Compile tab - click Add Jar/Folder button and select sqljdbc4.jarfile. Then it should be ok, right?
右键单击项目-> 选择属性-> 在左侧单击库-> 在编译选项卡下 - 单击添加 Jar/文件夹按钮并选择sqljdbc4.jar文件。那应该没问题吧？
Then I wrote this code But I cant get rid of this exception:
然后我写了这段代码但是我无法摆脱这个异常：
Exception in thread "main" java.lang.ClassNotFoundException:
com.microsoft.sqlserver.jdbc.SqlServerDriver
at java.net.URLClassLoader.run(URLClassLoader.java:366)
at java.net.URLClassLoader.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:190)
at javaapplication1.JavaApplication1.main(JavaApplication1.java:30)
This is the code
这是代码
public static void main(String[] args) throws ClassNotFoundException, SQLException {
String url = "jdbc:sqlserver://.\SQLEXPRESS;databaseName=Northwind; Integrated Security = SSPI ";
Connection con = null;
Statement stmt = null;
ResultSet rs = null;
try {
Class.forName("com.microsoft.sqlserver.jdbc.SqlServerDriver");
con = DriverManager.getConnection(url);
String sql = "Select Top 3 from * person.Contact";
stmt = con.createStatement();
rs = stmt.executeQuery(sql);
while (rs.next()) {
System.out.println(rs.getString(1));
}
} catch (Exception e) {
e.printStackTrace();
}
}
采纳答案by Jesper
According to this page, the class is called SQLServerDriverand not SqlServerDriver. Case is important!
根据此页面，该类被调用SQLServerDriver而不是SqlServerDriver。案例很重要！
So, try:
所以，试试：
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Note that with newer versions of JDBC, it's not necessary to load the driver class explicitly with Class.forName(...). The page I linked to explicitly explains that you don't have to do it. So, you can just remove the whole line and then it should work.
请注意，对于较新版本的 JDBC，没有必要使用Class.forName(...). 我链接到的页面明确说明您不必这样做。因此，您可以删除整行，然后它应该可以工作。
回答by sanjib kumar Panigrahi
Java: JDBC Connectivity with MSSQL in NetBeans
Java：在 NetBeans 中使用 MSSQL 的 JDBC 连接
Steps
脚步
- Download JDBC from: https://www.microsoft.com/en-in/download/details.aspx?id=11774
- Run sqljdbc__enu.exe - unpack this zip file in %Program Files (x86)% with the default directory: Microsoft JDBC DRIVER for SQL Server
- Create your new project in NetBeans
- Right Click on the project - select Properties - select Libraries from left panel - click Add JAR/Folder button - select your JAR file and open - ok
- Open Sql Server Configuration Manager - select Protocols for SQLEXPRESS under Sql Server Network Configuration - Right Click on TCP/IP - select Properties - change Enable to Yes - Click IP Addresses - Goto IPAll - Change TCP Dynamic Ports to 49169 and TCP Port to 1433 - Apply - Ok - Restart the Computer
- Open Run and type Services.msc - Start SQL Server Browser
- Goto project and write code for database connectivity.
- 从以下位置下载 JDBC：https: //www.microsoft.com/en-in/download/details.aspx?id=11774
- 运行 sqljdbc__enu.exe - 将此 zip 文件解压到 %Program Files (x86)% 中，默认目录为：Microsoft JDBC DRIVER for SQL Server
- 在 NetBeans 中创建新项目
- 右键单击项目 - 选择属性 - 从左侧面板中选择库 - 单击添加 JAR/文件夹按钮 - 选择您的 JAR 文件并打开 - 确定
- 打开Sql Server配置管理器-在Sql Server网络配置下选择SQLEXPRESS的协议-右键单击TCP/IP-选择属性-将启用更改为是-单击IP地址-转到IPAll-将TCP动态端口更改为49169，将TCP端口更改为1433-应用 - 确定 - 重新启动计算机
- 打开运行并键入 Services.msc - 启动 SQL Server 浏览器
- 转到项目并编写用于数据库连接的代码。
Code for Local Database Connectivity:
本地数据库连接代码：
String url = "jdbc:sqlserver://YOUR PC NAME;instanceName=SQLEXPRESS;DatabaseName=dbname;integratedSecurity=true";
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
Connection myCon = DriverManager.getConnection(url);
Statement myStmt = myCon.createStatement();
ResultSet myRs = myStmt.executeQuery("select * from table name");
