C3P0连接池

逃离我推掉我的手 2022-03-28 03:05 298阅读 0赞

**目录**

1.导入所需的jar文件

2.项目目录结构

c3p0-config.xml

C3P0Util.java

C3P0Demo.java

结果

数据库

--------------------

# 1.导入所需的jar文件 #

c3p0-0.9.5.2.jar

machange-commons-java-0.2.11.jar

前两个下载方式：[https://blog.csdn.net/qq\_32965187/article/details/86147216][https_blog.csdn.net_qq_32965187_article_details_86147216]

mysql-connector-java-8.0.12.jar

下载方式：[https://blog.csdn.net/qq\_32965187/article/details/83141405][https_blog.csdn.net_qq_32965187_article_details_83141405]

# 2.项目目录结构 #

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyOTY1MTg3_size_16_color_FFFFFF_t_70][]

## c3p0-config.xml ##

c3p0的配置文件，一定要用这个名字。

注意url的**&**要写成**&**

<?xml version="1.0" encoding="UTF-8"?>
    <c3p0-config>
      <default-config>
        <property name="driverClass">com.mysql.cj.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/bank?useSSL=false&serverTimezone=UTC</property>
        <property name="user">root</property>
        <property name="password">123456</property>
        
        <property name="initialPoolSize">10</property>
        <property name="maxIdleTime">30</property>
        <property name="maxPoolSize">100</property>
        <property name="minPoolSize">10</property>
        <property name="maxStatements">200</property>
      </default-config>
    </c3p0-config>

## C3P0Util.java ##

package com.zhujunwei.util ;
    
    import java.sql.Connection;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.sql.Statement;
    import com.mchange.v2.c3p0.ComboPooledDataSource;
    
    
    public class C3P0Util {
    
    	static ComboPooledDataSource dataSource = null ;
    	static {
    		dataSource = new ComboPooledDataSource() ;
    	}
    	/**
    	 * 得到Connection连接
    	 * @return Connection
    	 * @throws SQLException 
    	 */
    	public  static Connection getConnection() throws SQLException {
    		return dataSource.getConnection();
    		
    	}
    	
    	/**
    	 * 释放资源
    	 * @param conn
    	 * @param st
    	 * @param rs
    	 */
    	public static void release(Connection conn , Statement st , ResultSet rs){
    		closeRs(rs);
    		closeSt(st);
    		closeConn(conn);
    	}
    	public static void release(Connection conn , Statement st){
    		closeSt(st);
    		closeConn(conn);
    	}
    
    	
    	private static void closeRs(ResultSet rs){
    		try {
    			if(rs != null){
    				rs.close();
    			}
    		} catch (SQLException e) {
    			e.printStackTrace();
    		}finally{
    			rs = null;
    		}
    	}
    	
    	private static void closeSt(Statement st){
    		try {
    			if(st != null){
    				st.close();
    			}
    		} catch (SQLException e) {
    			e.printStackTrace();
    		}finally{
    			st = null;
    		}
    	}
    	
    	private static void closeConn(Connection conn){
    		try {
    			if(conn != null){
    				conn.close();
    			}
    		} catch (SQLException e) {
    			e.printStackTrace();
    		}finally{
    			conn = null;
    		}
    	}
    }

## C3P0Demo.java ##

package com.zhujunwei;
    
    import java.sql.Connection;
    import java.sql.PreparedStatement;
    import org.junit.Test;
    import com.zhujunwei.util.C3P0Util;
    
    
    public class C3P0Demo {
    	@Test
    	public void testC3P0() {
    		Connection conn = null ;
    		PreparedStatement ps = null ;
    		try {
    			
    			//得到连接对象
    			conn = C3P0Util.getConnection();
    			
    			String sql = "insert into account values(null,?,?)";
    			ps = conn.prepareStatement(sql);
    			ps.setString(1, "c3p0");
    			ps.setInt(2, 100);
    			ps.executeUpdate();
    		} catch (Exception e) {
    			e.printStackTrace();
    		} finally {
    			C3P0Util.release(conn, ps);
    		}
    	}
    }

## 结果 ##

一切正常！

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyOTY1MTg3_size_16_color_FFFFFF_t_70 1][]

## 数据库 ##

一切ok!

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyOTY1MTg3_size_16_color_FFFFFF_t_70 2][]

[https_blog.csdn.net_qq_32965187_article_details_86147216]: https://blog.csdn.net/qq_32965187/article/details/86147216
[https_blog.csdn.net_qq_32965187_article_details_83141405]: https://blog.csdn.net/qq_32965187/article/details/83141405
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyOTY1MTg3_size_16_color_FFFFFF_t_70]: /images/20220328/a4a65fccf6f64753b0ef93177ba25fca.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyOTY1MTg3_size_16_color_FFFFFF_t_70 1]: /images/20220328/c796222275d04303928c0fed839abfb6.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMyOTY1MTg3_size_16_color_FFFFFF_t_70 2]: /images/20220328/3ae08a2ff01740a4a2a56b3e8c6782cd.png