package com.c3p0.test;import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import com.mchange.v2.c3p0.ComboPooledDataSource;public class C3p0_first {// 数据库连接池ComboPooledDataSourceprivate static ComboPooledDataSource ds = null;// 在静态代码块中创建数据库连接池static {try {// 通过代码创建C3P0数据库连接池// 创建连接池对象ds = new ComboPooledDataSource();// 获取数据库连接ds.setDriverClass("com.mysql.jdbc.Driver");ds.setJdbcUrl("jdbc:mysql://localhost:3306/test02");ds.setUser("root");ds.setPassword("root");ds.setInitialPoolSize(10);// 初始化的连接数，取值应在为10ds.setMinPoolSize(5);//连接池中保留的最小连接数ds.setMaxPoolSize(20);//连接池中保留的最大连接数
} catch (Exception e) {e.printStackTrace();}}// 从数据源中获取数据库连接的方法public static Connection getConnection() throws SQLException {// 从数据源中获取数据库连接return ds.getConnection();}// 释放链接public static void release(Connection conn) {if (conn != null) {try {// 将Connection连接对象还给数据库连接池
                conn.close();} catch (Exception e) {e.printStackTrace();}}}
}

package com.c3p0.test;import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;import com.c3p0.enity.Employee;
import com.c3p0.jdbcUtils.JdbcUtils_C3P0;public class Testc3p0 {public List<Employee> queryAll(){String sql = "select * from emp";Connection conn = null;PreparedStatement st = null;ResultSet rs = null;Employee ee = null;//创建一个集合来接受查询的数据List<Employee> list=new ArrayList<>();try {// 获取数据库连接conn = C3p0_first.getConnection();st = conn.prepareStatement(sql);// 执行SQL语句rs = st.executeQuery();// 返回结果while (rs.next()) {ee = new Employee(rs.getString(1), rs.getString(2), rs.getString(3), rs.getString(4), rs.getString(5),rs.getString(6), rs.getString(7));list.add(ee);System.out.println(list);}} catch (Exception e) {e.printStackTrace();} finally {// 释放资源
            JdbcUtils_C3P0.release(conn);}return list;}}

package com.c3p0.enity;public class Employee {private String  EmpId;private String  Empname;private String  Pwd; private String  LoginDate;private String  Adress;private String  Jod;private String  Email;public Employee() {super();}public Employee(String empname, String pwd, String loginDate, String adress, String jod, String email) {super();Empname = empname;Pwd = pwd;LoginDate = loginDate;Adress = adress;Jod = jod;Email = email;}public Employee(String empId, String empname, String pwd, String loginDate, String adress, String jod,String email) {super();EmpId = empId;Empname = empname;Pwd = pwd;LoginDate = loginDate;Adress = adress;Jod = jod;Email = email;}public String getEmpId() {return EmpId;}public void setEmpId(String empId) {EmpId = empId;}public String getEmpname() {return Empname;}public void setEmpname(String empname) {Empname = empname;}public String getPwd() {return Pwd;}public void setPwd(String pwd) {Pwd = pwd;}public String getLoginDate() {return LoginDate;}public void setLoginDate(String loginDate) {LoginDate = loginDate;}public String getAdress() {return Adress;}public void setAdress(String adress) {Adress = adress;}public String getJod() {return Jod;}public void setJod(String jod) {Jod = jod;}public String getEmail() {return Email;}public void setEmail(String email) {Email = email;}}

package com.c3p0.test;import java.util.List;
import com.c3p0.enity.Employee;public class Test {public static void main(String[] args) {Testc3p0 tc=new Testc3p0();List<Employee> list=tc.queryAll();for(Employee ee:list){System.out.println(ee.getEmpname()+"\t"+ee.getAdress()+"\t"+ee.getEmail()+"\t"+ee.getLoginDate()+"\t");}}}

<c3p0-config>  <!--  C3P0的缺省(默认)配置，-->  <!-- 如果在代码中“ComboPooledDataSourceds = new ComboPooledDataSource();”这样写就表示使用的是C3P0的缺省(默认)配置信息来创建数据源 -->  <default-config>  <property name="driverClass">com.mysql.jdbc.Driver</property>  <property name="jdbcUrl">jdbc:mysql://localhost:3306/test02</property>  <property name="user">root</property>  <property name="password">root</property>  <!--当连接池中的连接耗尽的时候c3p0一次同时获取的连接数。Default:3 -->  <property name="acquireIncrement">5</property>  <!--初始化的连接数，取值应在minPoolSize与maxPoolSize之间。Default: 3-->  <property name="initialPoolSize">10</property>  <!--连接池中保留的最小连接数-->  <property name="minPoolSize">5</property>  <!--连接池中保留的最大连接数。Default:15 -->  <property name="maxPoolSize">20</property>  <!--定义在从数据库获取新连接失败后重复尝试的次数。Default: 30 -->  <property name="acquireRetryAttempts">30</property>  <!--两次连接中间隔时间，单位毫秒。Default: 1000 -->  <property name="acquireRetryDelay">1000</property>  <!--连接关闭时默认将所有未提交的操作回滚。Default: false -->  <property name="autoCommitOnClose">false</property>  </default-config>
</c3p0-config>

package com.c3p0.test;import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import com.mchange.v2.c3p0.ComboPooledDataSource;public class C3p0_first {// 数据库连接池ComboPooledDataSourceprivate static ComboPooledDataSource ds = null;// 在静态代码块中创建数据库连接池static {try {// 通过代码创建C3P0数据库连接池// 创建连接池对象/*ds = new ComboPooledDataSource();// 获取数据库连接ds.setDriverClass("com.mysql.jdbc.Driver");ds.setJdbcUrl("jdbc:mysql://localhost:3306/test02");ds.setUser("root");ds.setPassword("root");ds.setInitialPoolSize(10);// 初始化的连接数，取值应在为10ds.setMinPoolSize(5);//连接池中保留的最小连接数ds.setMaxPoolSize(20);//连接池中保留的最大连接数*/ds= new ComboPooledDataSource();} catch (Exception e) {e.printStackTrace();}}// 从数据源中获取数据库连接的方法public static Connection getConnection() throws SQLException {// 从数据源中获取数据库连接return ds.getConnection();}// 释放链接public static void release(Connection conn) {if (conn != null) {try {// 将Connection连接对象还给数据库连接池
                conn.close();} catch (Exception e) {e.printStackTrace();}}}
}