c3p0学习

**需要下载jar包：

               如果jar包版本是c3p0——0.9.5.1（包含0.9.5.1）以前的，只需一个jar包就可以,

               如果jar包版本是c3p0——0.9.5.2（包含0.9.5.2）之后的，另需一个mchange.jar包

接下来,新建配置文件:  c3p0-config.xml

 c3p0-config.xml:

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
	<!-- 这是默认配置信息 -->
	<default-config name="mysqlname">
		<!-- 连接四大参数配置 -->
		<property name="jdbcUrl">jdbc:mysql://211.68.191.30:3306/flag_test</property>
		<property name="driverClass">com.mysql.jdbc.Driver</property>
		<property name="user">root</property>
		<property name="password">Knorray101326#!</property>
		<!-- 池参数配置 -->
		<property name="acquireIncrement">10</property>
		<property name="initialPoolSize">10</property>
		<property name="maxIdleTime">120</property>
		<property name="minPoolSize">40</property>
		<property name="maxPoolSize">10</property>
	</default-config>
</c3p0-config>

然后是JDBCUtil.java

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 JDBCUtil {
	private static DataSource ds = new ComboPooledDataSource("mysqlname");
	 
	// 获取连接池
		public static DataSource getDataSource() {
			return ds;
		}
	 
	// 获取连接
		public static Connection getConnection() throws SQLException {
			return ds.getConnection();
		}
	 
		/**
		 * 关闭连接
		 * @param resultSet
		 * @param pst
		 * @param connection
		 */
		public static void closeConnection(ResultSet resultSet, PreparedStatement pst, Connection connection) {
			if (resultSet != null) {
				try {
					resultSet.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
			}
			if (pst != null) {
				try {
					pst.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
			}
			if (connection != null) {
				try {
					connection.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
			}
		}
		/*
		//测试方法
		public static void main(String[] args) {
			//JDBCUtil dbUtil = new JDBCUtil();
			Connection connection;
			try {
				connection = JDBCUtil.getConnection();
				if (connection != null) {
					System.out.println("连接成功");
				} else {
					System.out.println("连接失败");
				}
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			
			
		}*/
}

数据库操作(DAO层):

//测试c3p0 , 插入方法
	public boolean insert(Student stu) throws Exception {
		String sql = "insert into student(yb_userid,yb_username,yb_college, yb_schoolname) VALUES(?,?,?,?);";
		Connection connection = jdbcUtil.getConnection();
		PreparedStatement pstmt = connection.prepareStatement(sql);
		pstmt.setString(1, stu.getYb_userid());
		pstmt.setString(2, stu.getYb_username());
		pstmt.setString(3, stu.getYb_college());
		pstmt.setString(4, stu.getYb_schoolname());
		int count = pstmt.executeUpdate();
		
		System.out.println("flag插入用户：" + stu.getYb_username()+ "count======" + count);
		jdbcUtil.closeConnection(null , pstmt, connection);
		return count > 0 ? true : false;
	}

Servlet层;

//测试插入
	private void add(HttpServletRequest request, HttpServletResponse response) throws IOException {
		StudentDao studentDao = new StudentDao();

		String yb_userid = "101";
		String yb_username = "梁振辉";
		String yb_college = "信息科学与技术学院";
		String yb_schoolname = "农大";
		int status = 0;
		int visit = 0;
		Student student = new Student();
		student.setYb_userid(yb_userid);
		student.setYb_username(yb_username);
		student.setYb_college(yb_college);
		student.setYb_schoolname(yb_schoolname);
		student.setStatus(status);
		student.setVisit(visit);
		try {
			studentDao.insert(student);
			
		} catch (Exception e) {
			e.printStackTrace();
		}
		
	}