C3P0数据库连接池配置攻略

C3P0数据库连接池配置攻略笔记

0x00 首先在Web 项目src根目录下建立c3p0-config.xml

<c3p0-config>
    <!-- This app is massive! -->
    <named-config name="hello_C3P0">
        <!-- 指定连接数据源的基本属性 -->
        <property name="user">root</property>
        <property name="password">root</property>
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://127.0.0.1:3306/testdb</property>

        <!-- 若数据库中连接数不足时，一次向数据库服务器申请多少个连接 -->
        <property name="acquireIncrement">50</property>
        <!-- 初始化数据库连接池时连接的数量 取值应在minPoolSize与maxPoolSize之间，默认为3 -->
        <property name="initialPoolSize">100</property>
        <!-- 数据库连接池中的最小的数据连接数 默认为：3 -->
        <property name="minPoolSize">50</property>
        <!-- 数据库连接池中的最大的数据连接数 默认值: 15 -->
        <property name="maxPoolSize">1000</property>

        <!--关闭连接时，是否提交未提交的事务，默认为false，即关闭连接，回滚未提交的事务 -->
        <property name="autoCommitOnClose">false</property>

        <!-- C3P0数据库连接池可以维护的Statement的个数 -->
        <property name="maxStatements">0</property>
        <!-- 每个连接同时可以使用的Statements的个数 -->
        <property name="maxStatementsPerConnection">5</property>

        <!-- he's important, but there's only one of him -->
     <user-overrides user="master-of-the-universe"> 
      <property name="acquireIncrement">1</property>
      <property name="initialPoolSize">1</property>
      <property name="minPoolSize">1</property>
      <property name="maxPoolSize">5</property>
      <property name="maxStatementsPerConnection">50</property>
    </user-overrides>

    </named-config>
</c3p0-config>

0x01 创建工具类

JDBCTools.java

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import com.mchange.v2.c3p0.ComboPooledDataSource;

/**
 * @author SuperXingyun 
 * */
public class JDBCTools {

    private static ComboPooledDataSource dataSource=null;

    static{
        dataSource=new ComboPooledDataSource("hello_C3P0");
    }
    public static Connection getConnection() throws SQLException {

        return dataSource.getConnection();
    }

    public static void close(Connection con, Statement stmt, ResultSet rs) {
        // java.sql.Satement,import java.sql.ResultSet,import
        // java.sql.Connection;
        try {
            if (con != null)
                con.close();
            if (stmt != null)
                stmt.close();
            if (rs != null)
                rs.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public static void close(Object obj) {
        try {
            if (obj instanceof Connection && obj != null)
                ((Connection) obj).close();
            if (obj instanceof Statement && obj != null)
                ((Statement) obj).close();
            if (obj instanceof ResultSet && obj != null)
                ((ResultSet) obj).close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

0x02 调用方法：

Connection connection = JDBCTools.getConnection();

    ...
    private Connection connection;
    private PreparedStatement preparedStatement;
    private ResultSet resultSet;

    @Override
    public void insertClassMate(ClassMate mCLassMate) {
        // TODO Auto-generated method stub
        try {
            // 获得数据库链接
            connection = JDBCTools.getConnection();//调用方式
            // 构造SQL数据库插入语句
            String sqlString = "insert t_class(ClassName)values(?)";
            preparedStatement = connection.prepareStatement(sqlString);
            preparedStatement.setString(1,mCLassMate.getClassName());
            preparedStatement.executeUpdate();

        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                preparedStatement.close();
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
    ...

Tips:

Just put the files lib/c3p0-0.9.5.2.jar and lib/mchange-commons-java-0.2.11.jar
in your application’s effective CLASSPATH,

c3p0 最新版jar 包传送门: https://sourceforge.net/projects/c3p0/files/latest/download