在Eclipse上实现简单的JDBC增删查改操作

在Javaweb的学习里，学到了如何完成简单的增删查改操作，在这里撰写一篇文章以便自己整理回忆。

• 首先要建立一些包和导入一些文件、建一些类。具体框架如图

•  编写Product类

public class Product {

    private long id;
    private String productName;
    private long dir_id;
    private double salePrice;
    private String supplier;
    private String brand;
    private double cutoff;
    private double costPrice;

    public long getId() {
        return id;
    }

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

    public String getProductName() {
        return productName;
    }

    public void setProductName(String productName) {
        this.productName = productName;
    }

    public long getDir_id() {
        return dir_id;
    }

    public void setDir_id(long dir_id) {
        this.dir_id = dir_id;
    }

    public double getSalePrice() {
        return salePrice;
    }

    public void setSalePrice(double salePrice) {
        this.salePrice = salePrice;
    }

    public String getSupplier() {
        return supplier;
    }

    public void setSupplier(String supplier) {
        this.supplier = supplier;
    }

    public String getBrand() {
        return brand;
    }

    public void setBrand(String brand) {
        this.brand = brand;
    }

    public double getCutoff() {
        return cutoff;
    }

    public void setCutoff(double cutoff) {
        this.cutoff = cutoff;
    }

    public double getCostPrice() {
        return costPrice;
    }

    public void setCostPrice(double costPrice) {
        this.costPrice = costPrice;
    }

    @Override
    public String toString() {
        return "Product [id=" + id + ", productName=" + productName + ", dir_id=" + dir_id + ", salePrice=" + salePrice
                + ", supplier=" + supplier + ", brand=" + brand + ", cutoff=" + cutoff + ", costPrice=" + costPrice
                + "]";
    }

    public Product(long id, String productName, long dir_id, double salePrice, String supplier, String brand,
            double cutoff, double costPrice) {
        super();
        this.id = id;
        this.productName = productName;
        this.dir_id = dir_id;
        this.salePrice = salePrice;
        this.supplier = supplier;
        this.brand = brand;
        this.cutoff = cutoff;
        this.costPrice = costPrice;
    }

    public Product() {
        super();
    }

}

• 编写IProductDao类

import java.util.List;

import github.domain.Product;

public interface IProductDao {

    /*
     * 根据id删除产品
     */
    public void deleteProductById(long id);
    
    /*
     * 更新数据的操作
     */
    public void updateProduct(Product product);

    /*
     * 查询数据的操作,根据id
     */
    public Product queryProductById(long id);

    /*
     * 查询所有的产品
     */
    public List<Product> queryAllProduct();

    /*
     * 新增数据
     */
    public void addProduct(Product product);

}

• 编写ProductDaoImpl类

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import github.dao.IProductDao;
import github.domain.Product;
import github.util.JDBCUtil;

public class ProductDaoImpl implements IProductDao {

JDBCUtil jdbc = JDBCUtil.getInstance();
    
    @Override
    public void deleteProductById(long id) {
        Connection connection = null;
        PreparedStatement pst = null;
        try {
            connection = jdbc.getConnection();
            pst = connection.prepareStatement("delete from product where id = ?");
            pst.setLong(1, id);
            pst.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }finally{
            jdbc.close(null, pst, connection);
        }
    }

    @Override
    public void updateProduct(Product product) {
        Connection connection = null;
        PreparedStatement pst = null;
        try {
            connection = jdbc.getConnection();
            pst = connection.prepareStatement("update product set productName = ? where id = ?");
            pst.setString(1, product.getProductName());
            pst.setLong(2, product.getId());
            pst.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }finally{
            jdbc.close(null, pst, connection);
        }
    }

    @Override
    public Product queryProductById(long id) {
        Product p1 = new Product();
        Connection connection = null;
        PreparedStatement pst = null;
        ResultSet rs = null;
        try {
            connection = jdbc.getConnection();
            pst = connection.prepareStatement("select * from product where id = ?");
            pst.setLong(1, id);
            rs = pst.executeQuery();
            while(rs.next()){
                String productName = rs.getString("productName");
                p1.setProductName(productName);
            }
            
        } catch (SQLException e) {
            e.printStackTrace();
        }finally{
            jdbc.close(rs, pst, connection);
        }
        return p1;
    }

    @Override
    public List<Product> queryAllProduct() {
        List<Product> list = new ArrayList<Product>();
        try {
            Connection connection = jdbc.getConnection();
            PreparedStatement pst = connection.prepareStatement("select * from product");
            ResultSet rs = pst.executeQuery();
            while(rs.next()){
                long id = rs.getLong("id");
                String productName = rs.getString("productName");
                long dir_id = rs.getLong("dir_id");
                double salePrice = rs.getDouble("salePrice");
                String supplier = rs.getString("supplier");
                String brand = rs.getString("brand");
                double cutoff = rs.getDouble("cutoff");
                double costPrice = rs.getDouble("costPrice");
                Product p = new Product(id, productName, dir_id, salePrice, supplier, brand, cutoff, costPrice);
                list.add(p);
            }
            
            
        } catch (SQLException e) {
            e.printStackTrace();
        }
        
        
        return list;
    }

    @Override
    public void addProduct(Product product) {
        String sql="insert into product (id,productName,dir_id,salePrice,supplier,brand,cutoff,costPrice) values(?,?,?,?,?,?,?,?)";
        Connection connection = null;
        PreparedStatement pst = null;
        try {
            connection = jdbc.getConnection();
            
            pst = connection.prepareStatement(sql);
            pst.setLong(1, product.getId());
            pst.setString(2, product.getProductName());
            pst.setLong(3, product.getDir_id());
            pst.setDouble(4, product.getSalePrice());
            pst.setString(5,product.getSupplier());
            pst.setString(6, product.getBrand());
            pst.setDouble(7, product.getCutoff());
            pst.setDouble(8, product.getCostPrice());
            
            pst.executeUpdate();
        }  catch (SQLException e) {
            e.printStackTrace();
        }finally{
            jdbc.close(null, pst, connection);
        }
    }
}

• 封装工具JDBCUtil类

/*
 * 操作JDBC的工具类
 */

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

public class JDBCUtil {

    
    private static JDBCUtil instace = null;
    private static Properties pro = null;
    static{
        try {
            pro = new Properties();
            //读取配置文件
            pro.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("git.properties"));
            Class.forName(pro.getProperty("jdbc.driver"));
            instace = new JDBCUtil();//创建对象
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    /*
     * 获取jdbcutil的对象
     */
    public static JDBCUtil getInstance(){
        return instace;
    }
    
    //2.获取连接
    public Connection getConnection() throws SQLException{
        return DriverManager.getConnection(pro.getProperty("jdbc.url"),pro.getProperty("jdbc.username"),pro.getProperty("jdbc.password"));
    }
    
    //3.关闭
    public void close(ResultSet rs,Statement st,Connection connection){
        try {
            if(rs!=null){
                rs.close();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }finally{
            try {
                if(st!=null){
                    st.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }finally{
                try {
                    if(connection!=null){
                        connection.close();
                    }
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    
}

• 编写git.properties

jdbc.driver = com.mysql.jdbc.Driver
jdbc.url = jdbc:mysql:///test
jdbc.username = root
jdbc.password = root

• 编写JDBCTest类

import java.util.List;

import org.junit.Test;

import github.dao.IProductDao;
import github.dao.impl.ProductDaoImpl;
import github.domain.Product;

public class JDBCTest {

    /*
     * 删除数据
     */
    IProductDao productDao = new ProductDaoImpl();
    @Test
    public void test() {
        productDao.deleteProductById(2);
    }

    /*
     * 更改数据
     */
    @Test
    public void testUpdate() {
        Product p1 = new Product();
        
        p1.setProductName("荧光闪烁");
        p1.setId(14);
        
        productDao.updateProduct(p1);
    }
    
    /*
     * 单查询
     */
    @Test
    public void testQuery() {
        Product p = productDao.queryProductById(22L);
        System.out.println(p);
    }
    
    /*
     * 多查询
     */
    @Test
    public void testAllQuery() {
        List<Product> queryAllProduct = productDao.queryAllProduct();
        for(Product p : queryAllProduct){
            System.out.println(p);
        }    
    }
    
    /*
     * 增加数据
     */
    @Test
    public void addProductTest() {
        Product p1 = new Product();
        
        p1.setId(5);
        p1.setProductName("荧光闪烁");
        p1.setDir_id(5);
        p1.setSalePrice(186.32);
        p1.setSupplier("可乐");
        p1.setBrand("可乐");
        p1.setCutoff(0.72);
        p1.setCostPrice(143.52);
        
        productDao.addProduct(p1);
    }
}

• 运行程序