jdbc详细练习

jdbc详细练习

目录

环境准备（数据库表tb_brand）

环境准备（实体类Brand）

测试

查询所有数据

添加功能

修改信息

删除数据

 细节

需要的jar包

druid.properties

DruidDemo.java

---

环境准备（数据库表tb_brand）

CREATE table tb_brand
(
-- id 主表
id int primary key auto_increment,
-- 品牌名称
brand_name varchar(20),
-- 企业名称
company_name varchar(20),
-- 排序字段
ordered int,
-- 描述信息
description varchar(100),
-- 状态：0：禁用1：启用
status int
);
-- 添加数据
INSERT into tb_brand (brand_name,company_name,ordered,description,status)
VALUES('三只松鼠','三只松鼠股份有限公司',5,'好吃不上火',0)，
('华为','华为科技有限公司',100,'华为致力于把数字世界带入每个人、每个家庭、每个组织、构建万物互联的智能世界',1),
('小米','小米科技有限公司',50,'are you ok',1);
		
		
SELECt * FROM tb_brand;

注：创建表时，最后一个不加逗号

环境准备（实体类Brand）

package com.chunmei.pojo;

public class Brand {
    public String getBrandName() {
        return brandName;
    }

    public Integer getStatus() {
        return status;
    }

    public void setStatus(Integer status) {
        this.status = status;
    }

    public String getCompanyName() {
        return companyName;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public Integer getOrdered() {
        return ordered;
    }

    public void setOrdered(Integer ordered) {
        this.ordered = ordered;
    }

    public void setCompanyName(String companyName) {
        this.companyName = companyName;
    }

    public void setBrandName(String brandName) {
        this.brandName = brandName;
    }

    //id 主键
    private   Integer id             ;
//品牌名称
    private  String brandName     ;
// 企业名称
    private  String companyName   ;
// 排序字段
    private  Integer ordered        ;
    // 描述信息
    private  String description    ;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    // 状态：0：禁用1：启用
    private Integer status ;


    @Override
    public String toString() {
        return "Brand{" +
                "id=" + id +
                ", brandName='" + brandName + ''' +
                ", companyName='" + companyName + ''' +
                ", ordered=" + ordered +
                ", description='" + description + ''' +
                ", status=" + status +
                '}';
    }
}

注：getting setting 方法& toString 方法

测试 查询所有数据

1.获取Connection

2.定义SQL：

3.获取PreparedStatement对象

4.设置参数：不需要

5.执行SQL

6.处理结果:List

7.释放资源

package com.chunmei.example;

import com.alibaba.druid.pool.DruidDataSourceFactory;
import com.chunmei.pojo.Brand;
import org.junit.Test;

import javax.sql.DataSource;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

//品牌数据增改改查
public class BrandTest {


    @Test
    public void testSelectAll() throws Exception {
   //1.获取Connection
        //3.加载配置文件
        Properties prop=new Properties();
        prop.load(new FileInputStream("E:/cm/jdbc/jdbc_demo/src/druid.properties"));
        //4.获取连接池对象
        DataSource dataSource= DruidDataSourceFactory.createDataSource(prop);
        //5.获取数据库连接Connection
        Connection con=dataSource.getConnection();
        //2.定义sql语句
        String sql="select * from tb_brand;";
        //3.获取pstmt对象
        PreparedStatement pstmt = con.prepareStatement(sql);
        //4.设置参数

        //5.执行sql
        ResultSet rs = pstmt.executeQuery();
        //6.处理结果List封装Brand对象，装载List集合
        Brand brand=null;
        List brands=new ArrayList<>();
        while(rs.next()){
            //获取数据
            int id = rs.getInt("id");
            String brandName = rs.getString("brand_name");
            String companyName = rs.getString("company_name");
            int ordered = rs.getInt("ordered");
            String description = rs.getString("description");
            int status = rs.getInt("status");
            //封装Brand对象
            brand=new Brand();
            brand.setId(id);
            brand.setBrandName(brandName);
            brand.setCompanyName(companyName);
            brand.setOrdered(ordered);
            brand.setDescription(description);
            brand.setStatus(status);
            //装在集合
            brands.add(brand);

        }
        System.out.println(brands);
    //7.释放资源
        rs.close();
        con.close();
        pstmt.close();

    }
}

运行结果

添加功能

1.sql

2.参数需要，除了id之外的所有参数信息

3.结果：Boolean

package com.chunmei.example;

import com.alibaba.druid.pool.DruidDataSourceFactory;
import com.chunmei.pojo.Brand;
import org.junit.Test;

import javax.sql.DataSource;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

//品牌数据添加
public class BrandTest {
    @Test
    public void testSelectAll() throws Exception {
        //接受页面提交的参数
        String brandName="小黄鸭";
        String companyName="yaya公司";
        int ordered=1;
        String description="可爱鸭";
        int status=1;
   //1.获取Connection
        //3.加载配置文件
        Properties prop=new Properties();
        prop.load(new FileInputStream("E:/cm/jdbc/jdbc_demo/src/druid.properties"));
        //4.获取连接池对象
        DataSource dataSource= DruidDataSourceFactory.createDataSource(prop);
        //5.获取数据库连接Connection
        Connection con=dataSource.getConnection();
        //2.定义sql语句
        String sql="INSERT into tb_brand (brand_name,company_name,ordered,description,status)value (?,?,?,?,?);";
        //3.获取pstmt对象
        PreparedStatement pstmt = con.prepareStatement(sql);
        //4.设置参数
        pstmt.setString(1,brandName);
        pstmt.setString(2,companyName);
        pstmt.setInt(3,ordered);
        pstmt.setString(4,brandName);
        pstmt.setInt(5,status);
        //5.执行sql
        int count = pstmt.executeUpdate();//影响行数
        //6.处理结果
        System.out.println(count>0);

        //7.释放资源
        con.close();
        pstmt.close();

    }
}

 结果

 

 修改信息

1.sql

2.参数需要，除了id之外的所有参数信息

3.结果：Boolean

package com.chunmei.example;

import com.alibaba.druid.pool.DruidDataSourceFactory;
import com.chunmei.pojo.Brand;
import org.junit.Test;

import javax.sql.DataSource;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

//品牌数据修改
public class BrandTest {
    @Test
    public void testSelectAll() throws Exception {
        //接受页面提交的参数
        String brandName="小米";
        String companyName="小米科技有限公司";
        int ordered=1000;
        String description="are you okk";
        int status=1;
        int id=3;
   //1.获取Connection
        //3.加载配置文件
        Properties prop=new Properties();
        prop.load(new FileInputStream("E:/cm/jdbc/jdbc_demo/src/druid.properties"));
        //4.获取连接池对象
        DataSource dataSource= DruidDataSourceFactory.createDataSource(prop);
        //5.获取数据库连接Connection
        Connection con=dataSource.getConnection();
        //2.定义sql语句
        String sql="update tb_brandn"+
                "set brand_name=?,n" +
                "company_name=?,n" +
                "ordered=?,n" +
                "description=?,n" +
                "status=?n"+
                "where id=?";
        //3.获取pstmt对象
        PreparedStatement pstmt = con.prepareStatement(sql);
        //4.设置参数
        pstmt.setString(1,brandName);
        pstmt.setString(2,companyName);
        pstmt.setInt(3,ordered);
        pstmt.setString(4,brandName);
        pstmt.setInt(5,status);
        pstmt.setInt(6,id);
        //5.执行sql
        int count = pstmt.executeUpdate();//影响行数
        //6.处理结果
        System.out.println(count>0);

        //7.释放资源
        con.close();
        pstmt.close();

    }
}

删除数据

1.sql

2.参数需要，需要id

3.结果：Boolean

package com.chunmei.example;

import com.alibaba.druid.pool.DruidDataSourceFactory;
import com.chunmei.pojo.Brand;
import org.junit.Test;

import javax.sql.DataSource;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

//品牌数据删除
public class BrandTest {
    @Test
    public void testSelectAll() throws Exception {
        //接受页面提交的参数
        int id=4;
   //1.获取Connection
        //3.加载配置文件
        Properties prop=new Properties();
        prop.load(new FileInputStream("E:/cm/jdbc/jdbc_demo/src/druid.properties"));
        //4.获取连接池对象
        DataSource dataSource= DruidDataSourceFactory.createDataSource(prop);
        //5.获取数据库连接Connection
        Connection con=dataSource.getConnection();
        //2.定义sql语句
        String sql="delete from tb_brand where id=?";
        //3.获取pstmt对象
        PreparedStatement pstmt = con.prepareStatement(sql);
        //4.设置参数
        pstmt.setInt(1,id);
        //5.执行sql
        int count = pstmt.executeUpdate();//影响行数
        //6.处理结果
        System.out.println(count>0);

        //7.释放资源
        con.close();
        pstmt.close();

    }
}

 细节  需要的jar包

链接：https://pan.baidu.com/s/1UPdVp9QXWyfXu4XfHaKcdg 提取码：iqx6

druid.properties

# druid.properties文件的配置
driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/dorm?useSSL=false&serverTimezone=GMT%2B8&allowMultiQueries=true 
username=root
password=123456
# 初始化连接数量
initialSize=5
# 最大连接数
maxActive=10
# 最大超时时间
maxWait=3000

DruidDemo.java

package com.chunmei.druid;

import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.FileInputStream;
import java.sql.Connection;

import java.util.Properties;
import java.util.PropertyPermission;

public class DruidDemo {
    
    public static void main(String[] args) throws Exception {
        Properties prop=new Properties();
        prop.load(new FileInputStream("jdbc_demo/src/druid.properties"));
        //4.获取连接池对象
        DataSource dataSource=DruidDataSourceFactory.createDataSource(prop);
        //5.获取数据库连接Connection

        Connection connection=dataSource.getConnection();
        System.out.println(connection);

    }

}