网络推广和网站推广的关系,新手做地方门户网站,企业网站域名,龙岗网站建设推广下面展示了连接SQL Server数据库的整个流程#xff1a;
加载数据库驱动建立数据库连接执行SQL语句处理结果关闭连接
在连接之前#xff0c;前提是确保数据库成功的下载#xff0c;创建#xff0c;配置好账号密码。
运行成功的代码#xff1a;
import java.sql.*;publi…下面展示了连接SQL Server数据库的整个流程
加载数据库驱动建立数据库连接执行SQL语句处理结果关闭连接
在连接之前前提是确保数据库成功的下载创建配置好账号密码。
运行成功的代码
import java.sql.*;public class sqlserverConnection {//驱动private static String cxDriver com.microsoft.sqlserver.jdbc.SQLServerDriver;//连接地址private static String cxUrl jdbc:sqlserver://172.16.100.1:1433;databaseNameabc;encryptfalse;//用户名private static String cxUser abc;//用户密码:数据库的密码private static String cxPassword abc;public static void main(String[] args) {try{Class.forName(cxDriver); //加载sqlserver的驱动类System.out.println(加载SQLServer驱动类成功!);}catch(ClassNotFoundException a){System.out.println(加载SQLServer驱动失败!);a.printStackTrace();}Connection dbconnull; //处理与特定数据库的连接try{dbconDriverManager.getConnection(cxUrl,cxUser,cxPassword);System.out.println(数据库连接成功!);dbcon.close();}catch(SQLException e){System.out.println(数据库连接失败!);e.printStackTrace();}}}
报错
Exception in thread main java.lang.UnsupportedClassVersionError: com/microsoft/sqlserver/jdbc/SQLServerDriver has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0at java.lang.ClassLoader.defineClass1(Native Method)at java.lang.ClassLoader.defineClass(ClassLoader.java:763)at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)at java.net.URLClassLoader.defineClass(URLClassLoader.java:468)at java.net.URLClassLoader.access$100(URLClassLoader.java:74)at java.net.URLClassLoader$1.run(URLClassLoader.java:369)at java.net.URLClassLoader$1.run(URLClassLoader.java:363)at java.security.AccessController.doPrivileged(Native Method)at java.net.URLClassLoader.findClass(URLClassLoader.java:362)at java.lang.ClassLoader.loadClass(ClassLoader.java:424)at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)at java.lang.ClassLoader.loadClass(ClassLoader.java:357)at java.lang.Class.forName0(Native Method)at java.lang.Class.forName(Class.java:264)at timeunit_test.sqlserverConnection.main(sqlserverConnection.java:17)问题在于用较高版本的jdk编译的class文件在低版本的JVM上运行所导致的通俗讲就是编译运行版本不匹配。
可惜我不是 看下jar包目录下是否存在多余的不需要的版本去除 我第一次jre8,jre11版本的都导入了导致驱动加载失败 使用cmd java -version 查看java javac版本 是否都匹配
加载驱动成功但是连接又失败了
com.microsoft.sqlserver.jdbc.SQLServerException: encrypt property is set to true and trustServerCertificate property is set to false but the driver could not establish a secure connection to SQL Server by using Secure Sockets Layer (SSL) encryption: Error: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target. ClientConnectionId:f903a939-f589-4052-89f8-580442a86a1bat com.microsoft.sqlserver.jdbc.SQLServerConnection.terminate(SQLServerConnection.java:4026)at com.microsoft.sqlserver.jdbc.TDSChannel.enableSSL(IOBuffer.java:1954)at com.microsoft.sqlserver.jdbc.SQLServerConnection.connectHelper(SQLServerConnection.java:3552)at com.microsoft.sqlserver.jdbc.SQLServerConnection.login(SQLServerConnection.java:3172)at com.microsoft.sqlserver.jdbc.SQLServerConnection.connectInternal(SQLServerConnection.java:3014)at com.microsoft.sqlserver.jdbc.SQLServerConnection.connect(SQLServerConnection.java:1836)at com.microsoft.sqlserver.jdbc.SQLServerDriver.connect(SQLServerDriver.java:1246)at java.sql.DriverManager.getConnection(DriverManager.java:664)at java.sql.DriverManager.getConnection(DriverManager.java:247)at timeunit_test.sqlserverConnection.main(sqlserverConnection.java:26)
Caused by: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target...这个问题最有效的办法是在连接地址Url后面加上encryptfalse。
执行SQL语句:
Statement statement connection.createStatement();
String sql SELECT * FROM mytable;
ResultSet resultSet statement.executeQuery(sql);上述代码中statement对象用于执行SQL语句。sql是要执行的SQL语句这里是一个简单的查询语句。executeQuery()方法用于执行查询语句并返回一个ResultSet对象用于获取查询结果。
处理结果
while (resultSet.next()) {int id resultSet.getInt(id);String name resultSet.getString(name);// 处理每一条查询结果
}上述代码中通过resultSet.next()方法判断是否还有下一条查询结果然后使用getInt()和getString()等方法获取查询结果中的具体字段值。
关闭连接
resultSet.close();
statement.close();
connection.close();上述代码中分别关闭resultSet、statement和connection对象释放相关资源。 参考大家的文档 https://blog.csdn.net/qq243920161/article/details/78971861 https://blog.csdn.net/m0_46669582/article/details/111685213 https://blog.csdn.net/qq_42759370/article/details/103350930 https://blog.csdn.net/qq_37917691/article/details/108262286 https://blog.csdn.net/Green_Hand_is_me/article/details/122272151 https://blog.csdn.net/qq_45835014/article/details/128268932 https://blog.csdn.net/qq_51391437/article/details/121051234
