Common configuration method of C3P0

1: The first way is very simple

C3p0.driverclass=com.mysql.jdbc.driver
c3p0.jdbcurl=jdbc:mysql://localhost:3308/database
c3p0.user= Root
c3p0.password=root

File name: C3p0.properties (placed under the SRC directory)
The program I write is relatively simple and can be used to test execution configuration.

Package jdbc.mysql;

Import java.sql.Connection;
Import java.sql.PreparedStatement;
Import Java.sql.ResultSet;
Import java.sql.SQLException;


Import Com.mchange.v2.c3p0.ComboPooledDataSource;

public class C3p0 {public
	static void Main (string[] args) throws SQLException {
	//database connection pooling will go to Classpath to find the configuration of the database by default.
		Combopooleddatasource data = new Combopooleddatasource ();
		Connection conn = Data.getconnection ();
		String sql = "SELECT * from table";
		PreparedStatement pstmt = conn.preparestatement (sql);
		ResultSet rs = Pstmt.executequery ();
		while (Rs.next ()) {
			System.out.println (rs.getstring (1));
		}
}}

2: The second way is very flexible and easy to use, but also very close to our usual hibernate and struts of the configuration file way
And it can provide services for multiple data sources, providing default-config and named-config two configuration modes.
In which the specific parameters can refer to the C3P0 document (http://www.mchange.com/projects/c3p0/) relatively simple. You can almost see the meaning by the name of the attribute.

<?xml version= "1.0" encoding= "UTF-8"?> <c3p0-config> <default-config> <property name= "User" > root</property> <property name= "password" >1234</property> <property name= "Driverclass" >com .mysql.jdbc.driver</property> <property name= "Jdbcurl" >jdbc:mysql://localhost:3306/database? characterencoding=utf-8&useoldaliasmetadatabehavior=true</property> <property name= "initialPoolSize ">2</property> <property name=" MaxIdleTime ">30</property> <property name=" Maxpoolsize "> 100</property> <property name= "minpoolsize" >2</property> </default-config> <named-co Nfig name= "Database" > <property name= "user" >root</property> <property name= "password" >root&lt ;/property> <property name= "Driverclass" >com.mysql.jdbc.Driver</property> <property name= "Jdbcur L ">jdbc:mysql://localhost:3308/database?characterencoding=utf-8&useoldaliasmetadatabehavior=true</property> <property name= "initialPoolSize ">2</property> <property name=" MaxIdleTime ">30</property> <property name=" Maxpoolsize "> 100</property> <property name= "minpoolsize" >2</property> </named-config> </c3p0-config& Gt

If you put C3p0-config.xml under the src directory, then you do not need to specify the configuration file, it will automatically find this profile, that is, in the program without writing System.setproperty (" Com.mchange.v2.c3p0.cfg.xml ", System.getproperty (" User.dir ") +"/config/c3p0-config.xml ");

Package jdbc.mysql;

Import java.sql.Connection;
Import java.sql.PreparedStatement;
Import Java.sql.ResultSet;
Import java.sql.SQLException;

Import Javax.sql.DataSource;

Import Com.mchange.v2.c3p0.ComboPooledDataSource;


public class C3p0jdbc {public
	static void Main (string[] args) throws SQLException {
		System.setproperty (" Com.mchange.v2.c3p0.cfg.xml ", System.getproperty (" User.dir ") +"/config/c3p0-config.xml ");
		The above profile  <default-config> 
		//constructor null value by default. Going to find the default configuration
		DataSource data = new Combopooleddatasource ();
		The configuration file above  <named-config name= "Database" >
		//If a value is passed in the constructor, the corresponding configuration is found.
		DataSource data1 = new Combopooleddatasource ("database");
		Connection conn = Data.getconnection ();
		Connection conn1 = Data1.getconnection ();
		String sql = "SELECT * from table";
		PreparedStatement pstmt = conn1.preparestatement (sql);
		ResultSet rs = Pstmt.executequery ();
		while (Rs.next ()) {
			System.out.println (rs.getstring (1));
		}
}}

3: This configuration is the least commonly used, more cumbersome, that is, all the configuration is written to the program.

Optional use

Import com.mchange.v2.c3p0.*;
........	
Combopooleddatasource CPDs = new Combopooleddatasource ();
Cpds.setdriverclass ("Org.postgresql.Driver"); Loads the JDBC driver            
cpds.setjdbcurl ("Jdbc:postgresql://localhost/testdb");
Cpds.setuser ("Dbuser");                                  
Cpds.setpassword ("Dbpassword");                                  

Cpds.setmaxstatements (180); 
Cpds.close ();