保姆级JDEC增删改查练习

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JDEC增删改查练习

准备

增

思路

代码

package com.yang.example;

import com.alibaba.druid.pool.DruidDataSourceFactory;
import com.yang.pojo.Brand;

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

/** * @author 缘友一世 * @date 2022/7/2-22:31 */
public class BrandTestAdd {
    
    public static void main(String[] args) throws Exception {
    
        testAdd();
    }
    /** * 添加 * 1.SQL：insert into tb_brand(brand_name,company_name,ordered,description,status) values(?,?,?,?,?); * 2. 参数：需要，除了id之外的所有参数信息 * 3. 结果：boolean */
    public static void testAdd() throws Exception {
    
        //接受页面提交的参数
        String brandName="香飘飘";
        String companyName="香飘飘";
        int ordered=1;
        String description="绕地球一圈";
        int status=1;

        //1. 获取Connection
        //3.加载配置文件
        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 conn = dataSource.getConnection();

        //2. 定义SQL
        @SuppressWarnings("SqlResolve")
        String sql="insert into tb_brand(brand_name,company_name,ordered,description,status) values(?,?,?,?,?);";
        //3. 获取pStmt对象
        PreparedStatement pStmt =conn.prepareStatement(sql);
        //4.设置参数
        pStmt.setString(1,brandName);
        pStmt.setString(2,companyName);
        pStmt.setInt(3,ordered);
        pStmt.setString(4,description);
        pStmt.setInt(5,status);

        //5. 执行sql
        int count = pStmt.executeUpdate();
        //6.处理结果
        if(count>0)
        {
    
            System.out.println("添加成功！");
        }
        else {
    
            System.out.println("添加失败！");
        }
        //7. 释放集合
        pStmt.close();
        conn.close();
    }
}

结果

删

思路

代码

package com.yang.example;

import com.alibaba.druid.pool.DruidDataSourceFactory;
import com.sun.org.apache.xpath.internal.SourceTree;

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

/** * @author 缘友一世 * @date 2022/7/3-9:13 */
public class BrandTestDelete {
    
    public static void main(String[] args) throws Exception {
    
        testDelete();
    }
    /** * 删除 * delete from tb_brand where id=? */
    public static void testDelete() throws Exception {
    
        //接受页面提交的参数
        int id=6;
        //1.获取Connection
        //3.加载配置文件
        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.获取数据库对象
        Connection conn = dataSource.getConnection();
        //2.定义SQL
        @SuppressWarnings("SqlResolve")
        String sql="delete from tb_brand where id=?";
        //3.获取pStmt对象
        PreparedStatement pStmt = conn.prepareStatement(sql);
        //4.设置参数
        pStmt.setInt(1,id);
        //5.执行sql
        int count = pStmt.executeUpdate();
        //6.处理结果
        if(count>0) {
    
            System.out.println("删除成功！");
        }else {
    
            System.out.println("删除失败！");
        }
        //7.释放集合
        pStmt.close();
        conn.close();
    }
}

结果

改

思路

代码

package com.yang.example;

import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.FileInputStream;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.util.Properties;

/** * @author 缘友一世 * @date 2022/7/2-22:58 */
public class BrandTestUpdate {
    
    public static void main(String[] args) throws Exception {
    
        testUpdate();
    }

    /** * 修改 * 1. SQL update tb_brand set brand_name=?, company_name=?, ordered=?, description=?, status=? where id=? */
    public static void testUpdate() throws Exception {
    
        //接受页面提交的参数
        String brandName="香飘飘";
        String companyName="香飘飘";
        int ordered=1000;
        String description="绕地球三圈";
        int status=1;
        int id=6;

        //1. 获取Connection
        //3.加载配置文件
        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 conn = dataSource.getConnection();

        //2. 定义SQL
        @SuppressWarnings("SqlResolve")
        String sql="update tb_brand\n" +
                " set brand_name=?,\n" +
                " company_name=?,\n" +
                " ordered=?,\n" +
                " description=?,\n" +
                " status=?\n" +
                " where id=?";
        //3. 获取pStmt对象
        PreparedStatement pStmt =conn.prepareStatement(sql);
        //4.设置参数
        pStmt.setString(1,brandName);
        pStmt.setString(2,companyName);
        pStmt.setInt(3,ordered);
        pStmt.setString(4,description);
        pStmt.setInt(5,status);
        pStmt.setInt(6,id);

        //5. 执行sql
        int count = pStmt.executeUpdate();
        //6.处理结果
        if(count>0)
        {
    
            System.out.println("修改成功！");
        }
        else {
    
            System.out.println("修改失败！");
        }
        //7. 释放集合
        pStmt.close();
        conn.close();
    }
}

结果

查

思路

代码

package com.yang.example;

import com.alibaba.druid.pool.DruidDataSourceFactory;
import com.yang.pojo.Brand;

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;

/** * @author 缘友一世 * @date 2022/7/2-15:24 * 品牌数据的增删改查 */
public class BrandTextSelect {
    
    public static void main(String[] args) {
    
        try {
    
            testSelectAll();
        } catch (Exception e) {
    
            e.printStackTrace();
        }
    }

    /** * 查询所有 * 1.SQL;select * from tb_brand * 2.参数：不需要 * 3.结果：List<Brand> */
    public static void testSelectAll() throws Exception {
    
        //1. 获取Connection
        //3.加载配置文件
        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 conn = dataSource.getConnection();

        //2. 定义SQL
        @SuppressWarnings("SqlResolve")
        String sql="select * from tb_brand";
        //3. 获取pStmt对象
        PreparedStatement pStmt =conn.prepareStatement(sql);
        //4.设置参数

        //5. 执行sql
        ResultSet rs=pStmt.executeQuery();
        //6.处理结果 List<Brand>封装Brand对象，装载List集合
        Brand brand=null;
        List<Brand> 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);
            //封装集合
            brands.add(brand);
        }
        System.out.println(brands);
        //7. 释放集合
        rs.close();
        pStmt.close();
        conn.close();
    }
}

结果