在Eclipse上实现简单的JDBC增删查改操作

Posted 2021-02-21 subeiLY

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

  1 public class Product {
  2 
  3     private long id;
  4     private String productName;
  5     private long dir_id;
  6     private double salePrice;
  7     private String supplier;
  8     private String brand;
  9     private double cutoff;
 10     private double costPrice;
 11 
 12     public long getId() {
 13         return id;
 14     }
 15 
 16     public void setId(long id) {
 17         this.id = id;
 18     }
 19 
 20     public String getProductName() {
 21         return productName;
 22     }
 23 
 24     public void setProductName(String productName) {
 25         this.productName = productName;
 26     }
 27 
 28     public long getDir_id() {
 29         return dir_id;
 30     }
 31 
 32     public void setDir_id(long dir_id) {
 33         this.dir_id = dir_id;
 34     }
 35 
 36     public double getSalePrice() {
 37         return salePrice;
 38     }
 39 
 40     public void setSalePrice(double salePrice) {
 41         this.salePrice = salePrice;
 42     }
 43 
 44     public String getSupplier() {
 45         return supplier;
 46     }
 47 
 48     public void setSupplier(String supplier) {
 49         this.supplier = supplier;
 50     }
 51 
 52     public String getBrand() {
 53         return brand;
 54     }
 55 
 56     public void setBrand(String brand) {
 57         this.brand = brand;
 58     }
 59 
 60     public double getCutoff() {
 61         return cutoff;
 62     }
 63 
 64     public void setCutoff(double cutoff) {
 65         this.cutoff = cutoff;
 66     }
 67 
 68     public double getCostPrice() {
 69         return costPrice;
 70     }
 71 
 72     public void setCostPrice(double costPrice) {
 73         this.costPrice = costPrice;
 74     }
 75 
 76     @Override
 77     public String toString() {
 78         return "Product [id=" + id + ", productName=" + productName + ", dir_id=" + dir_id + ", salePrice=" + salePrice
 79                 + ", supplier=" + supplier + ", brand=" + brand + ", cutoff=" + cutoff + ", costPrice=" + costPrice
 80                 + "]";
 81     }
 82 
 83     public Product(long id, String productName, long dir_id, double salePrice, String supplier, String brand,
 84             double cutoff, double costPrice) {
 85         super();
 86         this.id = id;
 87         this.productName = productName;
 88         this.dir_id = dir_id;
 89         this.salePrice = salePrice;
 90         this.supplier = supplier;
 91         this.brand = brand;
 92         this.cutoff = cutoff;
 93         this.costPrice = costPrice;
 94     }
 95 
 96     public Product() {
 97         super();
 98     }
 99 
100 }

View Code

• 编写IProductDao类

 1 import java.util.List;
 2 
 3 import github.domain.Product;
 4 
 5 public interface IProductDao {
 6 
 7     /*
 8      * 根据id删除产品
 9      */
10     public void deleteProductById(long id);
11     
12     /*
13      * 更新数据的操作
14      */
15     public void updateProduct(Product product);
16 
17     /*
18      * 查询数据的操作,根据id
19      */
20     public Product queryProductById(long id);
21 
22     /*
23      * 查询所有的产品
24      */
25     public List<Product> queryAllProduct();
26 
27     /*
28      * 新增数据
29      */
30     public void addProduct(Product product);
31 
32 }

View Code

• 编写ProductDaoImpl类

  1 import java.sql.Connection;
  2 import java.sql.PreparedStatement;
  3 import java.sql.ResultSet;
  4 import java.sql.SQLException;
  5 import java.util.ArrayList;
  6 import java.util.List;
  7 
  8 import github.dao.IProductDao;
  9 import github.domain.Product;
 10 import github.util.JDBCUtil;
 11 
 12 public class ProductDaoImpl implements IProductDao {
 13 
 14 JDBCUtil jdbc = JDBCUtil.getInstance();
 15     
 16     @Override
 17     public void deleteProductById(long id) {
 18         Connection connection = null;
 19         PreparedStatement pst = null;
 20         try {
 21             connection = jdbc.getConnection();
 22             pst = connection.prepareStatement("delete from product where id = ?");
 23             pst.setLong(1, id);
 24             pst.executeUpdate();
 25         } catch (SQLException e) {
 26             e.printStackTrace();
 27         }finally{
 28             jdbc.close(null, pst, connection);
 29         }
 30     }
 31 
 32     @Override
 33     public void updateProduct(Product product) {
 34         Connection connection = null;
 35         PreparedStatement pst = null;
 36         try {
 37             connection = jdbc.getConnection();
 38             pst = connection.prepareStatement("update product set productName = ? where id = ?");
 39             pst.setString(1, product.getProductName());
 40             pst.setLong(2, product.getId());
 41             pst.executeUpdate();
 42         } catch (SQLException e) {
 43             e.printStackTrace();
 44         }finally{
 45             jdbc.close(null, pst, connection);
 46         }
 47     }
 48 
 49     @Override
 50     public Product queryProductById(long id) {
 51         Product p1 = new Product();
 52         Connection connection = null;
 53         PreparedStatement pst = null;
 54         ResultSet rs = null;
 55         try {
 56             connection = jdbc.getConnection();
 57             pst = connection.prepareStatement("select * from product where id = ?");
 58             pst.setLong(1, id);
 59             rs = pst.executeQuery();
 60             while(rs.next()){
 61                 String productName = rs.getString("productName");
 62                 p1.setProductName(productName);
 63             }
 64             
 65         } catch (SQLException e) {
 66             e.printStackTrace();
 67         }finally{
 68             jdbc.close(rs, pst, connection);
 69         }
 70         return p1;
 71     }
 72 
 73     @Override
 74     public List<Product> queryAllProduct() {
 75         List<Product> list = new ArrayList<Product>();
 76         try {
 77             Connection connection = jdbc.getConnection();
 78             PreparedStatement pst = connection.prepareStatement("select * from product");
 79             ResultSet rs = pst.executeQuery();
 80             while(rs.next()){
 81                 long id = rs.getLong("id");
 82                 String productName = rs.getString("productName");
 83                 long dir_id = rs.getLong("dir_id");
 84                 double salePrice = rs.getDouble("salePrice");
 85                 String supplier = rs.getString("supplier");
 86                 String brand = rs.getString("brand");
 87                 double cutoff = rs.getDouble("cutoff");
 88                 double costPrice = rs.getDouble("costPrice");
 89                 Product p = new Product(id, productName, dir_id, salePrice, supplier, brand, cutoff, costPrice);
 90                 list.add(p);
 91             }
 92             
 93             
 94         } catch (SQLException e) {
 95             e.printStackTrace();
 96         }
 97         
 98         
 99         return list;
100     }
101 
102     @Override
103     public void addProduct(Product product) {
104         String sql="insert into product (id,productName,dir_id,salePrice,supplier,brand,cutoff,costPrice) values(?,?,?,?,?,?,?,?)";
105         Connection connection = null;
106         PreparedStatement pst = null;
107         try {
108             connection = jdbc.getConnection();
109             
110             pst = connection.prepareStatement(sql);
111             pst.setLong(1, product.getId());
112             pst.setString(2, product.getProductName());
113             pst.setLong(3, product.getDir_id());
114             pst.setDouble(4, product.getSalePrice());
115             pst.setString(5,product.getSupplier());
116             pst.setString(6, product.getBrand());
117             pst.setDouble(7, product.getCutoff());
118             pst.setDouble(8, product.getCostPrice());
119             
120             pst.executeUpdate();
121         }  catch (SQLException e) {
122             e.printStackTrace();
123         }finally{
124             jdbc.close(null, pst, connection);
125         }
126     }
127 }

View Code

• 封装工具JDBCUtil类

 1 /*
 2  * 操作JDBC的工具类
 3  */
 4 
 5 import java.io.IOException;
 6 import java.sql.Connection;
 7 import java.sql.DriverManager;
 8 import java.sql.ResultSet;
 9 import java.sql.SQLException;
10 import java.sql.Statement;
11 import java.util.Properties;
12 
13 public class JDBCUtil {
14 
15     
16     private static JDBCUtil instace = null;
17     private static Properties pro = null;
18     static{
19         try {
20             pro = new Properties();
21             //读取配置文件
22             pro.load(Thread.currentThread().getContextClassLoader().getResourceAsStream("git.properties"));
23             Class.forName(pro.getProperty("jdbc.driver"));
24             instace = new JDBCUtil();//创建对象
25         } catch (ClassNotFoundException e) {
26             e.printStackTrace();
27         } catch (IOException e) {
28             e.printStackTrace();
29         }
30     }
31     
32     /*
33      * 获取jdbcutil的对象
34      */
35     public static JDBCUtil getInstance(){
36         return instace;
37     }
38     
39     //2.获取连接
40     public Connection getConnection() throws SQLException{
41         return DriverManager.getConnection(pro.getProperty("jdbc.url"),pro.getProperty("jdbc.username"),pro.getProperty("jdbc.password"));
42     }
43     
44     //3.关闭
45     public void close(ResultSet rs,Statement st,Connection connection){
46         try {
47             if(rs!=null){
48                 rs.close();
49             }
50         } catch (SQLException e) {
51             e.printStackTrace();
52         }finally{
53             try {
54                 if(st!=null){
55                     st.close();
56                 }
57             } catch (SQLException e) {
58                 e.printStackTrace();
59             }finally{
60                 try {
61                     if(connection!=null){
62                         connection.close();
63                     }
64                 } catch (SQLException e) {
65                     e.printStackTrace();
66                 }
67             }
68         }
69     }
70     
71 }

View Code

• 编写git.properties

1 jdbc.driver = com.mysql.jdbc.Driver
2 jdbc.url = jdbc:mysql:///test
3 jdbc.username = root
4 jdbc.password = root

View Code

• 编写JDBCTest类

 1 import java.util.List;
 2 
 3 import org.junit.Test;
 4 
 5 import github.dao.IProductDao;
 6 import github.dao.impl.ProductDaoImpl;
 7 import github.domain.Product;
 8 
 9 public class JDBCTest {
10 
11     /*
12      * 删除数据
13      */
14     IProductDao productDao = new ProductDaoImpl();
15     @Test
16     public void test() {
17         productDao.deleteProductById(2);
18     }
19 
20     /*
21      * 更改数据
22      */
23     @Test
24     public void testUpdate() {
25         Product p1 = new Product();
26         
27         p1.setProductName("荧光闪烁");
28         p1.setId(14);
29         
30         productDao.updateProduct(p1);
31     }
32     
33     /*
34      * 单查询
35      */
36     @Test
37     public void testQuery() {
38         Product p = productDao.queryProductById(22L);
39         System.out.println(p);
40     }
41     
42     /*
43      * 多查询
44      */
45     @Test
46     public void testAllQuery() {
47         List<Product> queryAllProduct = productDao.queryAllProduct();
48         for(Product p : queryAllProduct){
49             System.out.println(p);
50         }    
51     }
52     
53     /*
54      * 增加数据
55      */
56     @Test
57     public void addProductTest() {
58         Product p1 = new Product();
59         
60         p1.setId(5);
61         p1.setProductName("荧光闪烁");
62         p1.setDir_id(5);
63         p1.setSalePrice(186.32);
64         p1.setSupplier("可乐");
65         p1.setBrand("可乐");
66         p1.setCutoff(0.72);
67         p1.setCostPrice(143.52);
68         
69         productDao.addProduct(p1);
70     }
71 }

View Code

• 运行程序