标签:object 文件中 pass 数据库 print public nod rgs find
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>
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; } }
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; } }
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(); } }
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‘}
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
标签:object 文件中 pass 数据库 print public nod rgs find
原文地址:https://www.cnblogs.com/zhazhaacmer/p/10012728.html