java 代码实现读取Properties文件中的数据库配置信息

野性酷女 2023-10-18 18:04 156阅读 0赞

实例1:

  1. import java.io.FileNotFoundException;
  2. import java.io.FileReader;
  3. import java.io.IOException;
  4. import java.sql.Connection;
  5. import java.sql.DriverManager;
  6. import java.sql.ResultSet;
  7. import java.sql.SQLException;
  8. import java.sql.Statement;
  9. import java.util.Properties; 
  10. public class JDBC {
  11.      private static Properties pro=new Properties();
  13.      static{
  14.          try {
  15.             //getClassLoader()  动态加载类到JVM 中
  16.     pro.load(new FileReader(JDBC.class.getClassLoader()
  17.             .getResource("jdbc.properties").getPath()));
  18.          } catch (FileNotFoundException e) {
  19.              e.printStackTrace();
  20.          } catch (IOException e) {
  21.              e.printStackTrace();
  22.          }
  23.         }
  26.         public static Connection getConnection() {
  27.             Connection conn=null;
  28.             try {
  29.             Class.forName(pro.getProperty("Drivername"));
  30.                 conn=DriverManager.getConnection(
  31.                         pro.getProperty("url"), 
  32.                         pro.getProperty("username"), 
  33.                         pro.getProperty("password"));
  34.             } catch (Exception e) {
  35.                 e.printStackTrace();
  36.             }        
  37.             return conn;        
  38.         }
  40. }

实例2:

  1. import java.io.IOException;
  2. import java.sql.Connection;
  3. import java.sql.DriverManager;
  4. import java.sql.ResultSet;
  5. import java.sql.SQLException;
  6. import java.sql.Statement;
  7. import java.util.Properties;
  8. public class JDBC2 {
  10.     public static String driverClassName;
  11.     public static String url;
  12.     public static String username;
  13.     public static String password;
  15.     static {
  16.         Properties properties = new Properties();
  17.         try {
  18.             properties.load(JDBC2.class.getClassLoader().getResourceAsStream("jdbc.properties"));
  19.             driverClassName=properties.getProperty("Drivername");
  20.             url=properties.getProperty("url");
  21.             username=properties.getProperty("username");
  22.             password=properties.getProperty("password");
  23.         } catch (IOException e) {
  24.             // TODO Auto-generated catch block
  25.             e.printStackTrace();
  26.         }
  27.     }
  29.     public static Connection getconnection() {
  30.         Connection conn = null;
  31.         try {
  32.             Class.forName(driverClassName);
  33.             conn = DriverManager.getConnection(url, username, password);
  34.         } catch (Exception e) {
  35.             // TODO Auto-generated catch block
  36.             e.printStackTrace();
  37.         }
  38.         return conn;
  40.     } 
  41. }

实例3:

  1. import java.io.IOException;
  2. import java.io.InputStream;
  3. import java.sql.Connection;
  4. import java.sql.ResultSet;
  5. import java.sql.SQLException;
  6. import java.sql.Statement;
  7. import java.util.Properties;
  8. import org.apache.commons.dbcp2.BasicDataSource;
  9. import org.apache.commons.dbcp2.BasicDataSourceFactory;
  11. public class JDBC3 {
  12.     private static BasicDataSource dataSource;
  13.     static {
  14.         Properties properties = new Properties();
  15.         InputStream inputStream = JDBC3.class.getClassLoader().getResourceAsStream("jdbc.properties");
  16.         try {
  17.             properties.load(inputStream);
  18.             inputStream.close();
  19.             dataSource = BasicDataSourceFactory.createDataSource(properties);
  21.         } catch (IOException e) {
  22.             e.printStackTrace();
  23.         } catch (Exception e) {
  24.             e.printStackTrace();
  25.         }
  26.     }
  28.     public static Connection getconnection() throws SQLException{
  29.         return dataSource.getConnection();
  30.     }
  31. }

注意如果如下错误，解决方案：导入 commons-logging的jar包

watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0xvb2tpbmdUb21vcnJvdw_size_16_color_FFFFFF_t_70 注意如果如下错误，解决方案：导入 commons-pool2的jar包

watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0xvb2tpbmdUb21vcnJvdw_size_16_color_FFFFFF_t_70 1 即使用下面依赖中的三个jar包：

  1. <dependency>
  2.     <groupId>org.apache.commons</groupId>
  3.     <artifactId>commons-pool2</artifactId>
  4.     <version>2.6.2</version>
  5. </dependency>
  7. <dependency>
  8.     <groupId>commons-logging</groupId>
  9.     <artifactId>commons-logging</artifactId>
  10.     <version>1.2</version>
  11. </dependency>
  13. <dependency>
  14.     <groupId>org.apache.commons</groupId>
  15.     <artifactId>commons-dbcp2</artifactId>
  16.     <version>2.6.0</version>
  17. </dependency>

jdbc.properties 文件如下：

  1. Drivername=com.mysql.jdbc.Driver
  2. url=jdbc:mysql://127.0.0.1:3306/shujuku
  3. username=root
  4. password=123456

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