DBUtils的增删改查

数据准备：

CREATE DATABASE mybase;
USE mybase;
CREATE TABLE users(
uid INT PRIMARY KEY AUTO_INCREMENT,
username VARCHAR(64),
upassword VARCHAR(64)
);
INSERT INTO users (username,upassword) VALUES("zhangsan","123"),("lisi","456"),("wangwu","789");
SELECT * FROM users;

创建对应的类：

package DBUtils;

public class User {
    private int uid;
    private String username;
    private String upassword;

    public User() {
        // TODO Auto-generated constructor stub
    }

    public int getUid() {
        return uid;
    }

    public void setUid(int uid) {
        this.uid = uid;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getUpassword() {
        return upassword;
    }

    public void setUpassword(String upassword) {
        this.upassword = upassword;
    }

}

这里用到了C3P0连接池，抽取C3P0工具类：

package demo01;

import java.sql.Connection;
import java.sql.SQLException;

import javax.sql.DataSource;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class C3P0Utils {
    private static ComboPooledDataSource dataSource = new ComboPooledDataSource();

    public static DataSource getDataSource() {
        return dataSource;
    }

    public static Connection getConnection() {
        try {
            return dataSource.getConnection();
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }
}

C3P0配置文件：c3p0-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>

    <default-config>
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql:///mybase</property>
        <property name="user">root</property>
        <property name="password">xuyiqing</property>
        <property name="initialPoolSize">5</property>
        <property name="maxPoolSize">20</property>
    </default-config>

    <named-config name="yiqing">
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql:///mybase</property>
        <property name="user">root</property>
        <property name="password">xuyiqing</property>
    </named-config>

</c3p0-config>

测试类：

增删改：

package DBUtils;

import java.sql.SQLException;

import org.apache.commons.dbutils.QueryRunner;
import org.junit.Test;

import demo01.C3P0Utils;

/**
 * 测试DBUtils工具类的增删改操作
 */
public class TestDBUtils1 {

    /**
     * 添加所有用户方法
     */
    @Test
    public void testAddUser() {
        try {
            // 1.创建核心类QueryRunner
            QueryRunner qr = new QueryRunner(C3P0Utils.getDataSource());
            // 2.编写SQL语句
            String sql = "insert into users values(null,?,?)";
            // 3.为站位符设置值
            Object[] params = { "张三", "6666" };
            // 4.执行添加操作
            int rows = qr.update(sql, params);
            if (rows > 0) {
                System.out.println("添加成功!");
            } else {
                System.out.println("添加失败!");
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    /**
     * 根据id修改用户方法
     *
     */
    @Test
    public void testUpdateUserById() {
        try {
            // 1.创建核心类QueryRunner
            QueryRunner qr = new QueryRunner(C3P0Utils.getDataSource());
            // 2.编写SQL语句
            String sql = "update users set upassword=? where uid=?";
            // 3.为站位符设置值
            Object[] params = { "xxx", 1 };
            // 4.执行添加操作
            int rows = qr.update(sql, params);
            if (rows > 0) {
                System.out.println("修改成功!");
            } else {
                System.out.println("修改失败!");
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    /**
     * 根据id删除用户方法
     */
    @Test
    public void testDeleteUserById() {
        try {
            // 1.创建核心类QueryRunner
            QueryRunner qr = new QueryRunner(C3P0Utils.getDataSource());
            // 2.编写SQL语句
            String sql = "delete from users where uid=?";
            // 3.为站位符设置值
            Object[] params = {19};
            // 4.执行添加操作
            int rows = qr.update(sql, params);
            if (rows > 0) {
                System.out.println("删除成功!");
            } else {
                System.out.println("删除失败!");
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

查询操作相对复杂，独立来写：

package DBUtils;

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

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ColumnListHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;
import org.junit.Test;

import DBUtils.User;
import demo01.C3P0Utils;;

/**
 * 测试DBUtils查询操作
 */
public class TestDBUtils2 {

    /*
     * 查询所有用户方法
     */
    @Test
    public void testQueryAll() {
        try {
            // 1.获取核心类queryRunner
            QueryRunner qr = new QueryRunner(C3P0Utils.getDataSource());
            // 2.编写sql语句
            String sql = "select * from users";
            // 3.执行查询操作
            List<User> users = qr.query(sql, new BeanListHandler<User>(User.class));
            // 4.对结果集集合进行遍历
            for (User user : users) {
                System.out.println(user.getUsername() + " : " + user.getUpassword());
            }
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }

    /*
     * 根据id查询用户方法
     */
    @Test
    public void testQueryUserById() {
        try {
            // 1.获取核心类queryRunner
            QueryRunner qr = new QueryRunner(C3P0Utils.getDataSource());
            // 2.编写sql语句
            String sql = "select * from users where uid=?";
            //3.为占位符设置值
            Object[] params = {1};
            // 4.执行查询操作
            User user = qr.query(sql, new BeanHandler<User>(User.class), params);
            System.out.println(user.getUsername() + " : " + user.getUpassword());
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }

    /*
     * 根据所有用户的总个数
     */
    @Test
    public void testQueryCount() {
        try {
            // 1.获取核心类queryRunner
            QueryRunner qr = new QueryRunner(C3P0Utils.getDataSource());
            // 2.编写sql语句
            String sql = "select count(*) from users";
            // 4.执行查询操作
            Long count = (Long) qr.query(sql, new ScalarHandler());
            System.out.println(count);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }

    /*
     * 查询所有用户方法
     */
    @Test
    public void testQueryAll1() {
        try {
            // 1.获取核心类queryRunner
            QueryRunner qr = new QueryRunner(C3P0Utils.getDataSource());
            // 2.编写sql语句
            String sql = "select * from users";
            // 3.执行查询操作
            List<Map<String, Object>> list = qr.query(sql, new MapListHandler());
            // 4.对结果集集合进行遍历
            for (Map<String, Object> map : list) {
                System.out.println(map);
            }
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }

    /*
     * 查询所有用户方法
     */
    @Test
    public void testQueryAll2() {
        try {
            // 1.获取核心类queryRunner
            QueryRunner qr = new QueryRunner(C3P0Utils.getDataSource());
            // 2.编写sql语句
            String sql = "select * from users";
            // 3.执行查询操作
            List<Object> list = qr.query(sql, new ColumnListHandler("username"));
            // 4.对结果集集合进行遍历
            for (Object object : list) {
                System.out.println(object);
            }
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }
}