JDBC终章- 使用 DBUtils实现增删查改- C3P0Utils数据源/QueryRunner runner连接数据源并执行sql

Posted 2021-01-22 好好学习，天天向上

JDBC终章- 使用 DBUtils实现增删查改

1.数据库结构

Create Table

CREATE TABLE `user` (
  `id` int(3) NOT NULL AUTO_INCREMENT,
  `name` varchar(20) NOT NULL,
  `password` varchar(20) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8

 

2.工程结构

      SRC目录下的 c3p0-config.xml

<?xml version="1.0" encoding="UTF-8"?>

<c3p0-config>

  <named-config name="szs">
  
      <property name="user">root</property>
    <property name="password">123456</property>
    <property name="jdbcUrl">jdbc:mysql://localhost:3306/jdbc</property>
    <property name="driverClass">com.mysql.jdbc.Driver</property>
  
    <property name="acquireIncrement">2</property>
    <property name="initialPoolSize">5</property>
    <property name="minPoolSize">5</property>
    <property name="maxPoolSize">10</property>

    <property name="maxStatements">20</property> 
    <property name="maxStatementsPerConnection">5</property>

  </named-config>
</c3p0-config>

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      具体的JAR 包如下:

 

3.创建C3P0Utils 数据源

package day_23;

import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.junit.Test;

import javax.sql.DataSource;
import java.sql.SQLException;

public class C3P0Utils {
    private static DataSource ds;
    static {
        ds=new ComboPooledDataSource("szs");   //这里因为配置文件中没有default,故需要自定义的
    }
    public static DataSource getDataSource() throws SQLException {
        return ds;
    }
}

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4.创建DBUtilsDao类,实现增删查改

package day_23;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanListHandler;

import java.sql.SQLException;
import java.util.List;

//创建DBUtilsDao类
public class DBUtilsDao {
    //查询所有,返回List集合
    public List findAll() throws SQLException{
        //创建QueryRunner 对象
        QueryRunner runner=new QueryRunner(C3P0Utils.getDataSource()) ;
        //写SQL语句
        String sql="select * from user";
        //调用方法
        List list=(List)runner.query(sql,new BeanListHandler(User.class));
        return list;
    }
    //查询单个对象的id,返回List集合中的第一个对象
    public User find(int id) throws SQLException{
        //创建QueryRunner 对象
        QueryRunner runner=new QueryRunner(C3P0Utils.getDataSource()) ;
        //写SQL语句
        String sql="select * from user where id= ?";
        //调用方法
        List list=(List)runner.query(sql,new BeanListHandler(User.class),id);
        return (User)list.get(0);
    }
    //添加用户的操作
    public Boolean insert(User user) throws SQLException{
        //创建QueryRunner 对象
        QueryRunner runner=new QueryRunner(C3P0Utils.getDataSource()) ;
        //写SQL语句
        String sql="insert into user (name,password) values (?,?)";
        //调用方法
        int num=runner.update(sql,new Object[]{user.getName(),user.getPassword()});
        if(num>0){
            System.out.println("添加用户成功!");
            return true;
        }
        else
            return false;
    }
    //修改用户的操作
    public Boolean update(User user) throws SQLException{
            //创建QueryRunner 对象
            QueryRunner runner=new QueryRunner(C3P0Utils.getDataSource()) ;
            //写SQL语句
            String sql="update  user set name=?,password=? where id=?";
            //调用方法
            int num=runner.update(sql,new Object[]{user.getName(),user.getPassword(),user.getId()});
            if(num>0){
                System.out.println("更新用户成功!");
                find(user.getId()).toString();
                return true;
            }
            else
                return false;
    }
    //删除用户的操作 ,根据用户的id
    public Boolean delete(int id) throws SQLException{
        //创建QueryRunner 对象
        QueryRunner runner=new QueryRunner(C3P0Utils.getDataSource()) ;
        //写SQL语句
        String sql="delete from user where id =?";
        //调用方法
        int num=runner.update(sql,id);
        if(num>0){
            System.out.println("删除用户成功!");
            return true;
        }
        else
            return false;
    }

}

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5.测试DBUtilsDao类的 增(insert)删查改,四个功能

package day_23;

import java.sql.SQLException;
import java.util.List;

//测试增(insert)删查改,四个功能
public class DBUtilsDaoTest {
    private static DBUtilsDao dao=new DBUtilsDao();

    public static void testInsert() throws SQLException{
        User user=new User();
        user.setId(1);
        user.setName("赵六");
        user.setPassword("666666");
        boolean b=dao.insert(user);
        System.out.println(b);
    }
    public static void testDelete() throws SQLException{
        System.out.println(dao.delete(1));
    }
    public static void testfind() throws SQLException {
        System.out.println(dao.find(2));
    }
    public static void testfindAll() throws SQLException{
        List<User> users= dao.findAll();
        for(int i=0;i<users.size();i++)
            System.out.println(users.get(i));
    }
    public static void testUpdate() throws SQLException{
        User user=new User();
        user.setId(5);
        user.setName("赵六66");
        user.setPassword("666666");
        boolean b=dao.insert(user);
        System.out.println(b);
    }
    public static void main(String[] args) throws SQLException {
        testInsert();
        testDelete();
         testUpdate();
        testfind();
        testfindAll();


    }
}

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6.最终控制台的结果展示

添加用户成功!
true
false
添加用户成功!
true
User{id=2, name=\'李四\', password=\'123456\'}
User{id=2, name=\'李四\', password=\'123456\'}
User{id=3, name=\'王五\', password=\'123456\'}
User{id=4, name=\'赵六\', password=\'666666\'}
User{id=5, name=\'赵六\', password=\'666666\'}
User{id=6, name=\'赵六66\', password=\'666666\'}
User{id=7, name=\'赵六\', password=\'666666\'}
User{id=8, name=\'赵六66\', password=\'666666\'}