Java连接数据库的几种方式

最新推荐文章于 2025-03-21 19:36:52 发布

Leon Zhang121

最新推荐文章于 2025-03-21 19:36:52 发布

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Java连接数据库的几种方式

程序预览图：

第一种：最普通的方式，利用java原生jdbc连接数据库

package utils;

import java.sql.Connection;
importjava.sql.DriverManager;
importjava.sql.PreparedStatement;
import java.sql.ResultSet;
importjava.sql.SQLException;

public class JDBCUtilsDemo1{      
       static{
              /**
               *1. 加载驱动
               */
              try {
                     Class.forName("com.mysql.jdbc.Driver");    //利用反射加载驱动
              } catch (ClassNotFoundException e) {
                e.printStackTrace();     
              }
       }
       /**
        * 2.建立连接
        */
       public static Connection getConnection() {  
              try {
                     returnDriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/test?characterEncoding=utf-8","root", "root");
              } catch (SQLException e) {
                      throw newRuntimeException(e);
              }
       }
       /**
        * 关闭连接
        * @param conn
        * @param prep
        * @param rs
        */
       public static void close(Connection conn,PreparedStatementprep,ResultSet rs){
        if(rs != null){
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            } finally{
                rs = null;
            }
        }
        if(prep != null){
            try {
                prep.close();
            } catch (SQLException e) {
                e.printStackTrace();
            } finally{
                prep = null;
            }
        }
        if(conn != null){
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            } finally{
                conn = null;
            }
        }
    }
       /**
        * 测试数据库连通性
        */
       public static void main(String[] args) {
       Connection conn=JDBCUtilsDemo1.getConnection();
              System.out.println(conn);
              JDBCUtilsDemo1.close(conn,null, null);
       }
}

第二种：利用properties.properties配置文件形式，利用java原生jdbc连接数据库

配置文件：properties.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://127.0.0.1:3306/test?characterEncoding=utf-8
username=root
password=root

源代码：

package utils;

import java.sql.Connection;
importjava.sql.DriverManager;
importjava.sql.PreparedStatement;
import java.sql.ResultSet;
importjava.sql.SQLException;
import java.util.Properties;

public class JDBCUtilsDemo2{      
       private static Properties prop;
       static {
              prop = new Properties();
              try {
                     prop.load(JDBCUtilsDemo2.class.getClassLoader().getResourceAsStream(
                                   "db.properties"));
                     Class.forName(prop.getProperty("driver"));
              } catch (Exception e) {
                     throw new RuntimeException(e);
              }
       }
       public static Connection getConnection(Connection conn) {
              if (conn==null) {
                     try {
                            conn=DriverManager.getConnection(prop.getProperty("url"),
                                          prop.getProperty("username"),prop.getProperty("password"));
                     } catch (SQLException e) {
                            throw new RuntimeException(e);
                     }
              }
                return conn;   
       }
       public static void close(Connection conn,PreparedStatementprep,ResultSet rs){
        if(rs != null){
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            } finally{
                rs = null;
            }
        }
        if(prep != null){
            try {
                prep.close();
            } catch (SQLException e) {
                e.printStackTrace();
            } finally{
                prep = null;
            }
        }
        if(conn != null){
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            } finally{
                conn = null;
            }
        }
    }
public static voidmain(String[] args) {
       Connection conn = null;
       conn=JDBCUtilsDemo2.getConnection(conn);
       System.out.println(conn);
       JDBCUtilsDemo2.close(conn,null, null);
}     

}

第三种：利用c3p0-congig.xml配置文件形式，利用c3p0连接数据库

1.配置文件：c3p0-congig.xml

<c3p0-config>

       <default-config>

              <property name="jdbcUrl">jdbc:mysql://127.0.0.1:3306/test</property>

              <propertyname="driverClass">com.mysql.jdbc.Driver</property>

              <propertyname="user">root</property>

              <propertyname="password">root</property>

              <propertyname="initialPoolSize">3</property>

              <propertyname="maxPoolSize">6</property>

              <propertyname="maxIdleTime">1000</property>

       </default-config>

</c3p0-config>

2.源代码：

package utils;

 

import java.sql.Connection;

importjava.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

 

import javax.sql.DataSource;

 

importcom.mchange.v2.c3p0.ComboPooledDataSource;

public class JDBCUtilsDemo3{

       /**

        * 获得一个数据源

        */

        private staticDataSource dataSource=new ComboPooledDataSource();

        public staticDataSource getDataSources() {

              return dataSource;

       }

        /**

         * 获取连接

         */

        public staticConnection getConnection(){

                try {

                     return dataSource.getConnection();

              } catch (SQLException e) {

                     throw new RuntimeException(e);

              }

        }

        /**

               * 关闭连接

               * @param conn

               * @param prep

               * @param rs

               */

              public static void close(Connectionconn,PreparedStatement prep,ResultSet rs){

               if(rs != null){

                   try {

                      rs.close();

                   } catch(SQLException e) {

                      e.printStackTrace();

                   } finally{

                       rs =null;

                   }

               }

               if(prep !=null){

                   try {

                      prep.close();

                   } catch(SQLException e) {

                      e.printStackTrace();

                   } finally{

                       prep =null;

                   }

               }

               if(conn !=null){

                   try {

                      conn.close();

                   } catch(SQLException e) {

                      e.printStackTrace();

                   } finally{

                       conn =null;

                   }

               }

           }

              /**

               * 测试数据库连通性

               */

              public static void main(String[] args) {

                     Connection conn = null;

                  conn=JDBCUtilsDemo3.getConnection();

                     System.out.println(conn);

                     JDBCUtilsDemo1.close(conn,null, null);

              }

}

第四种：利用dbcp.properties配置文件形式，利用dbcp连接数据库

1配置文件:dbcp.properties


########DBCP配置文件##########

#####驱动名

driverClassName=com.mysql.jdbc.Driver

#####url

url=jdbc:mysql://127.0.0.1:3306/test

#####用户名

username=root

#####密码

password=root

#####初试连接数

initialSize=30

#####最大活跃数

maxTotal=30

#####最大idle数

maxIdle=10

#####最小idle数

minIdle=5

#####最长等待时间(毫秒)

maxWaitMillis=1000

####程序中的连接不使用后是否被连接池回收(该版本要使用removeAbandonedOnMaintenance和removeAbandonedOnBorrow)

#####removeAbandoned=true

removeAbandonedOnMaintenance=true

removeAbandonedOnBorrow=true

####连接在所指定的秒数内未使用才会被删除(秒)(为配合测试程序才配置为1秒)

removeAbandonedTimeout=1

2.源代码：

package utils;

import java.io.IOException;
import java.sql.Connection;
importjava.sql.PreparedStatement;
import java.sql.ResultSet;
importjava.sql.SQLException;
import java.util.Properties;
import javax.sql.DataSource;
importorg.apache.commons.dbcp.BasicDataSourceFactory;

public class JDBCUtilsDemo4{
       private static Properties props = new Properties();
       static {
              // 加载配置文件
              try {
                     props.load(JDBCUtilsDemo4.class.getClassLoader()
                                   .getResourceAsStream("dbcp.properties"));
              } catch (IOException e) {
                     throw new RuntimeException("配置文件加载失败");
              }
       }
       
       /**
        * 获得数据源
        *
        * @return
        */
       public static DataSource getDataSource() {
              try {
                     returnBasicDataSourceFactory.createDataSource(props);
              } catch (Exception e) {
                     throw new RuntimeException("获得数据源失败");
              }
       }
       
       /**
        * 获取连接
        *
        * @return
        */
       public static Connection getConnection() {
              try {
                     return getDataSource().getConnection();
              } catch (SQLException e) {
                     throw new RuntimeException("连接数据库失败");
              }
       }

       /**
        * 关闭连接
        *
        * @param conn
        * @param prep
        * @param rs
        */
       public static void close(Connection conn, PreparedStatementprep,
                     ResultSet rs) {
              if (rs != null) {
                     try {
                            rs.close();
                     } catch (SQLException e) {
                            e.printStackTrace();
                     } finally {
                            rs = null;
                     }
              }
              if (prep != null) {
                     try {
                            prep.close();
                     } catch (SQLException e) {
                            e.printStackTrace();
                     } finally {
                            prep= null;
                     }
              }
              if (conn != null) {
                     try {
                            conn.close();
                     } catch (SQLException e) {
                            e.printStackTrace();
                    } finally {
                            conn = null;
                     }
              }
       }

       /**
        * 测试数据库连通性
        */
       public static void main(String[] args) {
              Connection conn = null;
              conn = JDBCUtilsDemo4.getConnection();
              System.out.println(conn);
              JDBCUtilsDemo4.close(conn, null, null);
       }
}

第五种：利用mybatis-config.xml配置文件形式，利用MyBatis连接数据库

1配置文件:mybatis-config.xml

<?xmlversion="1.0" encoding="UTF-8" ?> 
<!DOCTYPEconfiguration 
  PUBLIC "-//mybatis.org//DTD Config3.0//EN" 
 "http://mybatis.org/dtd/mybatis-3-config.dtd"> 
<configuration>   
    <environmentsdefault="environment"> 
        <environmentid="environment"> 
            <transactionManager type="JDBC"/> 
            <dataSourcetype="POOLED"> 
                <propertyname="driver" value="com.mysql.jdbc.Driver" /> 
                <propertyname="url"value="jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&amp;characterEncoding=utf8"/> 
               <property name="username" value="root" /> 
                <propertyname="password" value="root" /> 
            </dataSource> 
        </environment> 
    </environments> 
     <!-- 加载SQL定义文件 -->
    <!-- <mappers> 
        <mapper resource=""/> 
    </mappers>     -->
</configuration>

2.源代码：

package utils;
importorg.apache.ibatis.session.SqlSession;
importorg.apache.ibatis.session.SqlSessionFactoryBuilder;

public class JDBCUtilsDemo5{
       private staticSqlSession session=null;
       public static SqlSession getSession(){
              try {
                     session= newSqlSessionFactoryBuilder().build(JDBCUtilsDemo5.class.getClassLoader().getResourceAsStream("mybatis-config.xml")).openSession();
              } catch (Exception e) {
                     throw new RuntimeException(e);
              }
              return session;
       }

    public static void close() {
          if(session!=null) {
                 session.close();
              }
       }

    public static void main(String[] args) {
          SqlSessionsession=null;
               session=JDBCUtilsDemo5.getSession();
               System.out.println(session);
               JDBCUtilsDemo5.close();
       }
}

第六种：利用hibernate.cfg.xml配置文件形式，利用hibernate连接数据库
1配置文件hibernate.cfg…xml

<?xml version='1.0'encoding='utf-8'?>
<!DOCTYPEhibernate-configuration PUBLIC
        "-//Hibernate/HibernateConfiguration DTD 3.0//EN"
       "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
    <session-factory>
        <!-- 数据库连接信息 -->         
     <propertyname="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
     <propertyname="hibernate.connection.url">jdbc:mysql://127.0.0.1:3306/test</property>
     <propertyname="hibernate.connection.username">root</property>  
     <propertyname="connection.password">root</property>
     <!-- hibernate配置信息 -->
        <!-- SQL dialect 方言，用于配置生成针对哪个数据库的-->
        <propertyname="dialect">
        <!-- 方言类，Hibernate提供的，用于封装某种特定的 -->
               org.hibernate.dialect.MySQL5Dialect
        </property>
        <!-- 生成的sql是否打印到控制台 -->
        <propertyname="show_sql">true</property> 
        <!-- 打印的sql是否进行格式化 -->    
        <propertyname="format_sql">true</property>
        <!-- 在配置文件中关联映射文件 -->
        <!-- <mappingresource=""/> -->
    </session-factory>
</hibernate-configuration>

2.源代码：

package utils;

import org.hibernate.Session;
importorg.hibernate.SessionFactory;
importorg.hibernate.cfg.Configuration;

@SuppressWarnings("deprecation")
public class JDBCUtilsDemo6{
       private static Configuration config;
       private static SessionFactory sessionFactory;
       private static Session session;
       static {
              // 1.加载hibernate.cfg.xml配置文件
              config = new Configuration().configure();
              // 2.获取SessionFactory
              sessionFactory = config.buildSessionFactory();
       }

       // 3.得到session
       public static Session getSession() {
              session = sessionFactory.openSession();
              return session;
       }
       
       // 4.关闭session
       public static void close() {
              if (session != null) {
                     session.close();
              }
       }

       public static void main(String[] args) {
              Session session = JDBCUtilsDemo6.getSession();
              System.out.println(session);
              JDBCUtilsDemo6.close();
       }
}