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