企业级应用开发 – 第55页

在本文章中，我们来学习Java中不同类型数据库的JDBC驱动程序库的使用。

1- 介绍

下面文章将介绍下载和使用一些数据库的JDBC驱动程序库。在这里，有关数据库类型如下：

Oracle
MySQL
SQL Server.

2- 对于Oracle的JDBC驱动程序

Oracle数据库库驱动程序通常命名为：ojdbc14.jar, ojdbc6.jar, … 所不同的是它打包的Java版本。

ojdbc14.jar: 由Java1.4版编译和打包
ojdbc6.jar: 由Java1.6版编译和打包

更多详细信息可以查看并从甲骨文网站下载：

http://www.oracle.com/technetwork/database/enterprise-edition/jdbc-112010-090769.html

可以下载 ojdbc6.jar 文件，它可以使用在不同版本(XE，10G，11G，12C)的Oracle数据库。目前几乎所有的 Java 应用程序使用 Java6 版本或更高版本。

要从甲骨文网站下载文件，必须有一个Oracle帐号(免费注册)。

为了节省时间，您可以通过以下链接下载：

https://code.google.com/p/afirs/downloads/detail?name=ojdbc6.jar

下载结果：

2.1- Maven关联Oracle JDBC驱动程序

   <repositories>
       <!-- Repository for ORACLE ojdbc6. -->
       <repository>
           <id>codelds</id>
           <url>https://code.lds.org/nexus/content/groups/main-repo</url>
       </repository>
   </repositories>
    .......
   <dependencies>
       ......
       <!-- Oracle database driver -->
       <dependency>
           <groupId>com.oracle</groupId>
           <artifactId>ojdbc6</artifactId>
           <version>11.2.0.3</version>
       </dependency>
       .......
   </dependencies>

2.2- 如何使用 (ojdbc)？

// Driver class:
oracle.jdbc.driver.OracleDriver

// URL Connection String: (SID)
String urlString ="jdbc:oracle:thin:@myhost:1521:mysid"


// URL Connection String:  (Service Name)
String urlString ="jdbc:oracle:thin:username/pass@//myhost:1521/myservicename"

// Or:
String urlString ="jdbc:oracle:thin:@myhost:1521/myservicename";

例如 JDBC 连接到 Oracle 数据库。

OracleConnUtils.java

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class OracleConnUtils {

   public static Connection getOracleConnection()
           throws ClassNotFoundException, SQLException {
       String hostName = "localhost";
       String sid = "db11g";
       String userName = "learningsql";
       String password = "1234";

       return getOracleConnection(hostName, sid, userName, password);
   }

   public static Connection getOracleConnection(String hostName, String sid,
           String userName, String password) throws ClassNotFoundException,
           SQLException {

      // Declare the class Driver for Oracle DB
      // This is necessary with Java 5 (or older)
      // Java6 (or newer) automatically find the appropriate driver.
      // If you use Java> 6, then this line is not needed.
       Class.forName("oracle.jdbc.driver.OracleDriver");

       // Example: jdbc:oracle:thin:@localhost:1521:db11g
       String connectionURL = "jdbc:oracle:thin:@" + hostName + ":1521:" + sid;

       Connection conn = DriverManager.getConnection(connectionURL, userName,
               password);
       return conn;
   }
}

3- MySQL的JDBC驱动程序

也可以下载MySQL数据库JDBC库在：

http://mvnrepository.com/artifact/mysql/mysql-connector-java

下载结果：

3.1- 如何使用？

如何使用MySQL-connector-java-xxx.jar : (JDBC for MySQL)

// Driver class:
com.mysql.jdbc.Driver

// URL Connection String:
String url = "jdbc:mysql://hostname:3306/dbname";


// Example:
String url = "jdbc:mysql://localhost:3306/simplehr";

例如，使用 JDBC 连接到 MySQL 数据库

MySQLConnUtils.java

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class MySQLConnUtils {

  public static Connection getMySQLConnection()
          throws ClassNotFoundException, SQLException {
      String hostName = "localhost";
      String dbName = "learningsql";
      String userName = "root";
      String password = "12345";
      return getMySQLConnection(hostName, dbName, userName, password);
  }

  public static Connection getMySQLConnection(String hostName, String dbName,
          String userName, String password) throws SQLException,
          ClassNotFoundException {
     // Declare the class Driver for Oracle DB
     // This is necessary with Java 5 (or older)
     // Java6 (or newer) automatically find the appropriate driver.
     // If you use Java> 5, then this line is not needed.
      Class.forName("com.mysql.jdbc.Driver");


      // Ví dụ: jdbc:mysql://localhost:3306/simplehr
      String connectionURL = "jdbc:mysql://" + hostName + ":3306/" + dbName;

      Connection conn = DriverManager.getConnection(connectionURL, userName,
              password);
      return conn;
  }
}

3.2- 有些问题出现，如何解决它

在某些情况下，Java连接或另一台计算机链接MySQL会发生出错。其原因可能是没有配置MySQL服务器，以允许其他计算机的连接。

4- JDBC SQLServer (JTDS)

JTDS是另一个SQL Server管理数据库的JDBC库，它是一个开源库。

JTDS是一个开源的100%纯Java(4类)JDBC3.0驱动程序的Microsoft SQL Server(6.5，7，2000，2005，2008，2012)和Sybase ASE(10，11，12，15)。JTDS基于freetds的，目前是SQL Server和Sybase最快生产就绪的JDBC驱动程序。JTDS是100%与JDBC 3.0兼容，只向前和可滚动/可更新结果集支持并执行所有的DatabaseMetaData和ResultSetMetaData方法。

您可以下载JTDS在：

http://mvnrepository.com/artifact/net.sourceforge.jtds/jtds

结果下载：

4.1- 如何使用(jtds)

使用方法：(用于SQL Server JDBC驱动程序)

// Driver Class
net.sourceforge.jtds.jdbc.Driver

// Connection URL String:
jdbc:jtds:<server_type>://<server>[:<port>][/<database>][;<property>=<value>[;...]]

// Example 1:
String url = "jdbc:jtds:sqlserver://MYPC:1433/simplehr;instance=SQLEXPRESS;user=sa;password=s3cr3t";

getConnection(url);

// Example 2:
String url = "jdbc:jtds:sqlserver://MYPC:1433/simplehr;instance=SQLEXPRESS";

getConnection(url, "sa", "s3cr3t"):

例如，使用JDBC连接到MySQL数据库(用JTDS库)

SQLServerConnUtils_JTDS.java

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class SQLServerConnUtils_JTDS {

 // Connect to SQLServer.
 // (Using JTDS library)
 public static Connection getSQLServerConnection_JTDS() throws SQLException,
         ClassNotFoundException {
     String hostName = "localhost";
     String sqlInstanceName = "SQLEXPRESS";
     String database = "simplehr";
     String userName = "sa";
     String password = "12345";

     return getSQLServerConnection_JTDS(hostName, sqlInstanceName, database,
             userName, password);
 }


 // JTDS & SQLServer.
 private static Connection getSQLServerConnection_JTDS(String hostName,
         String sqlInstanceName, String database, String userName,
         String password) throws ClassNotFoundException, SQLException {

    // Declare the class Driver for Oracle DB
    // This is necessary with Java 5 (or older)
    // Java6 (or newer) automatically find the appropriate driver.
    // If you use Java> 5, then this line is not needed.
     Class.forName("net.sourceforge.jtds.jdbc.Driver");

      // Example:
     // jdbc:jtds:sqlserver://localhost:1433/simplehr;instance=SQLEXPRESS
     String connectionURL = "jdbc:jtds:sqlserver://" + hostName + ":1433/"
             + database + ";instance=" + sqlInstanceName;

     Connection conn = DriverManager.getConnection(connectionURL, userName,
             password);
     return conn;
 }

}

4.2- 有些问题，如何解决它？

在某些情况下，我们连接到SQL Server可能会发生一些错误情况：

Exception in thread "main" java.sql.SQLException: Server tran-vmware has no instance named SQLEXPRESS.
   at net.sourceforge.jtds.jdbc.JtdsConnection.<init>(JtdsConnection.java:301)
   at net.sourceforge.jtds.jdbc.Driver.connect(Driver.java:184)
   at java.sql.DriverManager.getConnection(DriverManager.java:571)
   at java.sql.DriverManager.getConnection(DriverManager.java:215)
   at com.yiibai.tutorial.jdbc.ConnectionUtils.getSQLServerConnection_JTDS(ConnectionUtils.java:189)
   at com.yiibai.tutorial.jdbc.ConnectionUtils.getSQLServerConnection_JTDS(ConnectionUtils.java:72)
   at com.yiibai.tutorial.jdbc.ConnectionUtils.getMyConnection(ConnectionUtils.java:31)
   at com.yiibai.tutorial.jdbc.TestConnection.main(TestConnection.java:20)

存在上述错误，因为没有启用SQL Server的TCP/IP服务。

5- JDBC与 SQLServer (SQLJDBC)

SQLJDBC库是由微软提供的。

下载地址：

http://www.microsoft.com/en-us/download/details.aspx?id=11774

解压刚刚下载的文件。

解压后的结果如下：

5.1- 如何使用 (sqljdbc)

// Driver Class:
com.microsoft.sqlserver.jdbc.SQLServerDriver

Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");

// Url String:
String url = "jdbc:sqlserver://ServerIp;Instance=SQLEXPRESS;databaseName=simplehr";

// or
String url = "jdbc:sqlserver://ServerIp:1433;Instance=SQLEXPRESS;databaseName=simplehr";

String user = "dbUserID";
String pass = "dbUserPassword";

Connection connection = DriverManager.getConnection(url, user, pass);

例如，使用JDBC连接到SQLServer数据库(用SQLJDBC库)。

SQLServerConnUtils_SQLJDBC.java

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class SQLServerConnUtils_SQLJDBC {
 
  // Connect to SQLServer.
  // (Using SQLJDBC)
  public static Connection getSQLServerConnection_SQLJDBC()
          throws ClassNotFoundException, SQLException {
      String hostName = "localhost";
      String sqlInstanceName = "SQLEXPRESS";
      String database = "learningsql";
      String userName = "sa";
      String password = "12345";

      return getSQLServerConnection_SQLJDBC(hostName, sqlInstanceName,
              database, userName, password);
  }



  // SQLServer & SQLJDBC.
  private static Connection getSQLServerConnection_SQLJDBC(String hostName,
          String sqlInstanceName, String database, String userName,
          String password) throws ClassNotFoundException, SQLException {
     // Declare the class Driver for Oracle DB
     // This is necessary with Java 5 (or older)
     // Java6 (or newer) automatically find the appropriate driver.
     // If you use Java> 5, then this line is not needed.
      Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");


      // Example:
      // jdbc:sqlserver://ServerIp:1433/SQLEXPRESS;databaseName=simplehr
      String connectionURL = "jdbc:sqlserver://" + hostName + ":1433"
              + ";instance=" + sqlInstanceName + ";databaseName=" + database;

      Connection conn = DriverManager.getConnection(connectionURL, userName,
              password);
      return conn;
  }

}

5.2- 出现一些麻烦，如何解决它

在某些情况下，我们连接到SQL Server会发生一些错误情况：

com.microsoft.sqlserver.jdbc.SQLServerException: The TCP/IP connection to the host localhost, port 1433 has failed. Error: "Connection refused: connect. Verify the connection properties. Make sure that an instance of SQL Server is running on the host and accepting TCP/IP connections at the port. Make sure that TCP connections to the port are not blocked by a firewall.".
  at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:190)
  at com.microsoft.sqlserver.jdbc.SQLServerException.ConvertConnectExceptionToSQLServerException(SQLServerException.java:241)
  at com.microsoft.sqlserver.jdbc.SocketFinder.findSocket(IOBuffer.java:2243)
  at com.microsoft.sqlserver.jdbc.TDSChannel.open(IOBuffer.java:491)
  at com.microsoft.sqlserver.jdbc.SQLServerConnection.connectHelper(SQLServerConnection.java:1309)
  at com.microsoft.sqlserver.jdbc.SQLServerConnection.login(SQLServerConnection.java:991)
  at com.microsoft.sqlserver.jdbc.SQLServerConnection.connect(SQLServerConnection.java:827)
  at com.microsoft.sqlserver.jdbc.SQLServerDriver.connect(SQLServerDriver.java:1012)
  at java.sql.DriverManager.getConnection(Unknown Source)
  at java.sql.DriverManager.getConnection(Unknown Source)
  ...

如存在上述错误，因为可能没有启用SQL Server的TCP/IP服务。需要启动SQLServer服务，如果仍然出现以下错误：

Exception in thread "main" com.microsoft.sqlserver.jdbc.SQLServerException: The TCP/IP connection to the host tran-vmware, port 1433 has failed. Error: "Connection refused: connect. Verify the connection properties. Make sure that an instance of SQL Server is running on the host and accepting TCP/IP connections at the port. Make sure that TCP connections to the port are not blocked by a firewall.".
 at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(SQLServerException.java:190)
 at com.microsoft.sqlserver.jdbc.SQLServerException.ConvertConnectExceptionToSQLServerException(SQLServerException.java:241)
 at com.microsoft.sqlserver.jdbc.SocketFinder.findSocket(IOBuffer.java:2243)
 at com.microsoft.sqlserver.jdbc.TDSChannel.open(IOBuffer.java:491)
 at com.microsoft.sqlserver.jdbc.SQLServerConnection.connectHelper(SQLServerConnection.java:1309)
 at com.microsoft.sqlserver.jdbc.SQLServerConnection.login(SQLServerConnection.java:991)
 at com.microsoft.sqlserver.jdbc.SQLServerConnection.connect(SQLServerConnection.java:827)
 at com.microsoft.sqlserver.jdbc.SQLServerDriver.connect(SQLServerDriver.java:1012)
 at java.sql.DriverManager.getConnection(DriverManager.java:571)
 at java.sql.DriverManager.getConnection(DriverManager.java:215)
 ...

您应该考虑使用JTDS了

6- JDBC驱动和MongoDB

JDBC驱动程序MongoDB，你从下面的网址下载：

https://github.com/mongodb/mongo-java-driver/downloads

您也可以在Maven仓库下载：

http://mvnrepository.com/artifact/org.mongodb/mongo-java-driver

分类：企业级应用开发

Java JDBC连接各种数据库实例