029 c3p0的小测试

　　今天被问到这个问题，就实验了一下，后续会继续补充一些配置项的意思。

一：操作步骤

1.大纲

　　

2.新建sql

 -- ----------------------------
 -- Table structure for user
 -- ----------------------------
 DROP TABLE IF EXISTS `user`;
 CREATE TABLE `user` (
   `id` int(16) NOT NULL,
   `name` varchar(255) DEFAULT NULL,
   `password` varchar(255) DEFAULT NULL,
   `email` varchar(255) DEFAULT NULL,
   `phone` varchar(255) DEFAULT NULL,
   PRIMARY KEY (`id`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

 -- ----------------------------
 -- Records of user
 -- ----------------------------
 INSERT INTO `user` VALUES ('', 'aa', '', '12@qq.com', '');

3.domain

 package com.jun.it;

 public class User {
     private int id;
     private String name;
     private String password;
     private String email;
     private String phone;
     public int getId() {
         return id;
     }
     public void setId(int id) {
         this.id = id;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public String getPassword() {
         return password;
     }
     public void setPassword(String password) {
         this.password = password;
     }
     public String getEmail() {
         return email;
     }
     public void setEmail(String email) {
         this.email = email;
     }
     public String getPhone() {
         return phone;
     }
     public void setPhone(String phone) {
         this.phone = phone;
     }
     @Override
     public String toString() {
         return "User [id=" + id + ", name=" + name + ", password=" + password + ", email=" + email + ", phone=" + phone
                 + "]";
     }

 }

4.c3p0-config.xml

 <c3p0-config>

     <!-- c3p0默认配置，下面还可以配置多个数据库 -->
     <default-config>
         <property name="jdbcUrl">jdbc:mysql://127.0.0.1:3308/test?serverTimezone=UTC&amp;useUnicode=true&amp;characterEncoding=utf8&amp;useSSL=true</property>
         <property name="driverClass">com.mysql.cj.jdbc.Driver</property>
         <property name="user">root</property>
         <property name="password">123456</property>
         <property name="minPoolSize">5</property>
         <property name="maxPoolSize">2</property>
         <property name="maxIdleTime">10</property>
     </default-config>

 </c3p0-config>

5.测试类

 package com.jun.it;

 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.util.ArrayList;
 import java.util.List;

 import org.junit.Test;

 import com.mchange.v2.c3p0.ComboPooledDataSource;

 public class C3p0Test {
      //使用编码方式实现c3p0数据库连接池
     @Test
     public void TestXml() throws Exception{
         //第一步：创建连接池核心工具类
         ComboPooledDataSource dataSource=new ComboPooledDataSource();

         //第三步：从连接池对象中获取数据库连接
         Connection con=dataSource.getConnection();
         String sql="select * from user ";
         PreparedStatement ps=con.prepareStatement(sql);
         ResultSet rs=ps.executeQuery();

         List<User> list=new ArrayList<User>();
         while(rs.next()){
             User user=new User();
             user.setId(rs.getInt("id"));
             user.setName(rs.getString("name"));
             user.setPassword(rs.getString("password"));
             user.setEmail(rs.getString("email"));
             user.setPhone(rs.getString("phone"));
             list.add(user);
         }

         System.out.println("~~~"+list);
     }
 }

6.效果