增删改查
一.准备jar包
数据库驱动包
DBUtils包
C3P0连接池 的jar包
二.配置好C3P0的配置文件
1 <?xml version="1.0" encoding="UTF-8"?> 2 <c3p0-config> 3 <!-- 默认配置 --> 4 <default-config> 5 <property name="driverClass">com.mysql.jdbc.Driver</property> 6 <property name="jdbcUrl">jdbc:mysql:///day26</property> 7 <property name="user">root</property> 8 <property name="password">root</property> 9 10 <property name="automaticTestTable">con_test</property> 11 <property name="checkoutTimeout">30000</property> 12 <property name="idleConnectionTestPeriod">30</property> 13 <property name="initialPoolSize">10</property> 14 <property name="maxIdleTime">30</property> 15 <property name="maxPoolSize">100</property> 16 <property name="minPoolSize">10</property> 17 <property name="maxStatements">200</property> 18 <user-overrides user="test-user"> 19 <property name="maxPoolSize">10</property> 20 <property name="minPoolSize">1</property> 21 <property name="maxStatements">0</property> 22 </user-overrides> 23 </default-config> <!-- This app is massive! --> 24 <!-- 命名的配置 --> 25 <named-config name="my"> 26 <property name="acquireIncrement">50</property> 27 <property name="initialPoolSize">100</property> 28 <property name="minPoolSize">50</property> 29 <property name="maxPoolSize">1000</property> <!-- intergalactoApp adopts a different approach to configuring statement 30 caching --> 31 <property name="maxStatements">0</property> 32 <property name="maxStatementsPerConnection">5</property> <!-- he‘s important, but there‘s only one of him --> 33 <user-overrides user="master-of-the-universe"> 34 <property name="acquireIncrement">1</property> 35 <property name="initialPoolSize">1</property> 36 <property name="minPoolSize">1</property> 37 <property name="maxPoolSize">5</property> 38 <property name="maxStatementsPerConnection">50</property> 39 </user-overrides> 40 </named-config> 41 </c3p0-config>
三.准备好工具类
ThreadLocal工具类：
1 import java.sql.Connection; 2 import java.sql.SQLException; 3 4 public class ConnectionManager { 5 private static ThreadLocal<Connection> tl=new ThreadLocal<>(); 6 public static Connection getConnection() throws SQLException{ 7 Connection con=tl.get(); 8 if(con==null){ 9 con=MyC3P0Utils.getConnection(); 10 tl.set(con); 11 } 12 return con; 13 } 14 //开启事务 15 public static void begin() throws SQLException{ 16 getConnection().setAutoCommit(false); 17 } 18 //提交事务 19 public static void commit() throws SQLException{ 20 getConnection().commit(); 21 } 22 //回滚事务 23 24 public static void rollback() throws SQLException{ 25 getConnection().rollback(); 26 } 27 //关闭资源 28 public static void close() throws SQLException{ 29 getConnection().close(); 30 } 31 32 }
C3P0:
1 import java.sql.Connection; 2 import java.sql.SQLException; 3 import javax.sql.DataSource; 4 import com.mchange.v2.c3p0.ComboPooledDataSource; 5 public class MyC3P0Utils { 6 private static DataSource dataSource=new ComboPooledDataSource(); 7 public static DataSource getDataSource(){ 8 return dataSource; 9 } 10 public static Connection getConnection() throws SQLException{ 11 return dataSource.getConnection(); 12 } 13 14 }
四.Dao层代码：
1 public class ProductDao { 2 /** 3 * 查询所有数据 4 * @return Product泛型的List集合 5 * @throws SQLException 6 */ 7 public List<Products> findAll() throws SQLException{ 8 QueryRunner qr = new QueryRunner(MyC3P0Utils.getDataSource()); 9 List<Products> list = qr.query("select * from products",new BeanListHandler<>(Products.class)); 10 return list; 11 } 12 /** 13 * 通过id查找数据 14 * @param id 15 * @return 16 * @throws SQLException 17 */ 18 public Products findById(int id) throws SQLException{ 19 QueryRunner qr = new QueryRunner(MyC3P0Utils.getDataSource()); 20 Products product = qr.query("select * from products where pid=?",new BeanHandler<>(Products.class),id); 21 return product; 22 } 23 /** 24 * 插入数据 25 * @param products products类型的对象 26 * @return 影响行数 27 * @throws SQLException 28 */ 29 public int insertData(Products products) throws SQLException{ 30 QueryRunner qr = new QueryRunner(MyC3P0Utils.getDataSource()); 31 Object[] objects={products.getPname(),products.getPrice(),products.getCategory_id()}; 32 int re = qr.update("insert into products values(null,?,?,?)",objects); 33 return re; 34 } 35 /** 36 * 修改数据 37 * @param products 38 * @return 影响的行数 39 * @throws SQLException 40 */ 41 public int updateData(Products products) throws SQLException{ 42 QueryRunner qr = new QueryRunner(MyC3P0Utils.getDataSource()); 43 Object[] objects={products.getPname(),products.getPrice(),products.getCategory_id(),products.getPid()}; 44 int re = qr.update("update products set pname= ? ,price=? ,category_id=? where pid=?",objects); 45 return re; 46 } 47 /** 48 * 通过i删除产品 49 * @param pid 产品id 50 * @return 受影响的行数 51 * @throws SQLException 52 */ 53 public int deleteData(int pid) throws SQLException{ 54 QueryRunner qr = new QueryRunner(); 55 int re = qr.update(ConnectionManager.getConnection(),"delete from products where pid =?",pid); 56 return re; 57 } 58 59 }
五.Service层代码：
1 public class ProductService { 2 /** 3 *查询所有 4 * @return 5 */ 6 public List<Products> findAll(){ 7 ProductDao productDao=new ProductDao(); 8 List<Products> list =null; 9 try { 10 list = productDao.findAll(); 11 } catch (SQLException e) { 12 // TODO Auto-generated catch block 13 e.printStackTrace(); 14 } 15 return list; 16 } 17 /** 18 * 通过id 查询数据 19 * @param id 20 * @return 21 */ 22 public Products findById(int id){ 23 ProductDao productDao=new ProductDao(); 24 Products product=null; 25 try { 26 product = productDao.findById(id); 27 } catch (SQLException e) { 28 // TODO Auto-generated catch block 29 e.printStackTrace(); 30 } 31 return product; 32 33 } 34 /** 35 * 插入数据 36 * @param products 37 * @return 38 */ 39 public int insertData(Products products){ 40 ProductDao productDao=new ProductDao(); 41 int re=-1; 42 try { 43 re = productDao.insertData(products); 44 } catch (SQLException e) { 45 // TODO Auto-generated catch block 46 e.printStackTrace(); 47 } 48 return re; 49 } 50 /** 51 * 修改数据 52 * @param products 53 * @return 54 */ 55 public int updateData(Products products){ 56 ProductDao productDao=new ProductDao(); 57 int re=-1; 58 try { 59 re = productDao.updateData(products); 60 } catch (SQLException e) { 61 // TODO Auto-generated catch block 62 e.printStackTrace(); 63 } 64 return re; 65 66 } 67 /** 68 * 通过pid删除数据 69 * @param pid 70 * @return 71 */ 72 public int deleteData(int pid){ 73 ProductDao productDao=new ProductDao(); 74 int re= -1; 75 try { 76 re = productDao.deleteData(pid); 77 } catch (SQLException e) { 78 // TODO Auto-generated catch block 79 e.printStackTrace(); 80 } 81 return re; 82 } 83 84 public boolean deleteAll(HashSet<Integer> set){ 85 ProductDao productDao=new ProductDao(); 86 boolean flag=true; 87 try { 88 ConnectionManager.begin(); 89 for (Integer pid : set) { 90 91 int re = productDao.deleteData(pid); 92 93 if(!(re>0)){ 94 flag=false; 95 break; 96 } 97 } 98 if(flag){ 99 ConnectionManager.commit(); 100 return true; 101 }else{ 102 ConnectionManager.rollback(); 103 return false; 104 } 105 } catch (SQLException e) { 106 // TODO Auto-generated catch block 107 108 try { 109 ConnectionManager.rollback(); 110 } catch (SQLException e1) { 111 // TODO Auto-generated catch block 112 e1.printStackTrace(); 113 } 114 }finally{ 115 try { 116 ConnectionManager.close(); 117 } catch (SQLException e) { 118 // TODO Auto-generated catch block 119 e.printStackTrace(); 120 } 121 } 122 return false; 123 } 124 125 126 }
六 web层代码：
1 public class ProductWeb { 2 public static void main(String[] args) { 3 Scanner scanner=new Scanner(System.in); 4 while(true){ 5 System.out.println("请输入你的选择:"); 6 System.out.println("I:插入、U:修改、D:删除、DA:批量删除、QI：根据id查询、FA：查询所有、Q:退出"); 7 String string=scanner.nextLine().toUpperCase(); 8 9 switch (string) { 10 case "I": 11 insertData(scanner); 12 break; 13 case "U": 14 updateDate(scanner); 15 break; 16 case "D": 17 deleteData(scanner); 18 break; 19 case "DA": 20 deleteAll(scanner); 21 break; 22 case "QI": 23 findById(scanner); 24 break; 25 case "FA": 26 //查询所有 27 findAll(); 28 break; 29 case "Q": 30 System.out.println("是否要退出？（y/n）"); 31 String s1 = scanner.nextLine(); 32 if("y".equalsIgnoreCase(s1)){ 33 System.exit(0); 34 } 35 break; 36 default: 37 break; 38 } 39 40 41 } 42 43 } 44 /** 45 * 批量删除 46 * @param scanner 47 */ 48 private static void deleteAll(Scanner scanner) { 49 // TODO Auto-generated method stub 50 HashSet<Integer> set =new HashSet<>(); 51 ProductService productService=new ProductService(); 52 String regex="[1-9]([0-9]*)"; 53 while(true){ 54 System.out.println("请输入删除产品pid(输入-1停止)"); 55 /* String str=scanner.nextLine(); 56 if(!str.matches(regex)){ 57 System.out.println("不符合规则"); 58 continue; 59 } 60 int pid = Integer.parseInt(str);*/ 61 int pid =Integer.parseInt(scanner.nextLine()); 62 if(pid==-1){ 63 break; 64 } 65 Products product = productService.findById(pid); 66 if(product==null){ 67 System.out.println("没有该条数据"); 68 continue; 69 } 70 System.out.println(product); 71 set.add(pid); 72 } 73 System.out.println("你要删除的数据条数是"+set.size()); 74 System.out.println("请确认是否要删除？（y/n）"); 75 String choice = scanner.nextLine(); 76 if("y".equalsIgnoreCase(choice)){ 77 boolean flag = productService.deleteAll(set); 78 if(flag){ 79 System.out.println("删除成功"); 80 }else { 81 System.out.println("删除失败"); 82 } 83 } 84 85 } 86 /** 87 * 通过id删除 88 * @param scanner 89 */ 90 private static void deleteData(Scanner scanner) { 91 // TODO Auto-generated method stub 92 System.out.println("请输入要删除产品的id"); 93 String regex="[1-9]([0-9]*)"; 94 String str1 = scanner.nextLine(); 95 if(!str1.matches(regex)){ 96 System.out.println("输入格式不符合"); 97 return; 98 } 99 int pid = Integer.parseInt(str1); 100 ProductService productService=new ProductService(); 101 Products product = productService.findById(pid); 102 if(product==null){ 103 System.out.println("没有数据"); 104 return; 105 } 106 System.out.println("你要删除的产品数据是，确定要删除吗？（y/n）"); 107 System.out.println(product); 108 String choice = scanner.nextLine(); 109 if(!"y".equalsIgnoreCase(choice)){ 110 System.out.println("输入有误，返回菜单"); 111 return; 112 } 113 int re = productService.deleteData(pid); 114 if(re>0){ 115 System.out.println("删除成功"); 116 }else { 117 System.out.println("删除失败"); 118 } 119 } 120 /** 121 * 修改产品 122 * @param scanner 123 */ 124 private static void updateDate(Scanner scanner) { 125 // TODO Auto-generated method stub 126 System.out.println("请输入要修改产品的pid"); 127 String regex="[1-9]([0-9]*)"; 128 String str = scanner.nextLine(); 129 if(!str.matches(regex)){ 130 System.out.println("格式不正确"); 131 return ; 132 } 133 int pid = Integer.parseInt(str); 134 ProductService productService=new ProductService(); 135 Products product = productService.findById(pid); 136 if(product==null){ 137 System.out.println("没有数据"); 138 return; 139 } 140 System.out.println("请输入新的名字"); 141 String pname=scanner.nextLine(); 142 System.out.println("请输入新的价格"); 143 double price = Double.parseDouble(scanner.nextLine()); 144 System.out.println("请输入类别，（1是电子，2是服装，3是化妆品）"); 145 int category_id = Integer.parseInt(scanner.next()); 146 product.setCategory_id(category_id); 147 product.setPname(pname); 148 product.setPrice(price); 149 int re = productService.updateData(product); 150 if(re>0){ 151 System.out.println("修改成功"); 152 }else{ 153 System.out.println("修改失败"); 154 } 155 } 156 /** 157 * 插入数据 158 * @param scanner 159 */ 160 private static void insertData(Scanner scanner) { 161 System.out.println("请输入产品名称"); 162 String pname = scanner.nextLine(); 163 System.out.println("请输入价格"); 164 double price = Double.parseDouble(scanner.nextLine()); 165 System.out.println("请输入类别，（1是电子，2是服装，3是化妆品）"); 166 int cate = Integer.parseInt(scanner.next()); 167 ProductService productService=new ProductService(); 168 Products products=new Products(); 169 products.setPname(pname); 170 products.setPrice(price); 171 products.setCategory_id(cate); 172 int re = productService.insertData(products); 173 if(re>0){ 174 System.out.println("插入成功"); 175 } 176 } 177 /** 178 * 通过id 查询数据 179 * @param scanner 180 */ 181 private static void findById(Scanner scanner) { 182 // TODO Auto-generated method stub 183 System.out.println("请输入要查询的pid"); 184 185 String regex="[1-9]([0-9]*)"; 186 String str = scanner.nextLine(); 187 if(!str.matches(regex)){ 188 System.out.println("输入格式不符合"); 189 return; 190 } 191 int pid = Integer.parseInt(str); 192 ProductService productService=new ProductService(); 193 Products product = productService.findById(pid); 194 if(product==null){ 195 System.out.println("没有数据"); 196 return; 197 } 198 System.out.println(product); 199 } 200 /** 201 * 查询所有 202 */ 203 private static void findAll() { 204 ProductService productService=new ProductService(); 205 List<Products> list = productService.findAll(); 206 if(list==null){ 207 System.out.println("查询出错"); 208 return; 209 } 210 if(list.size()==0){ 211 System.out.println("没有数据"); 212 return; 213 } 214 for (Products products : list) { 215 System.out.println(products.getPid()+"\t"+products.getPname()+"\t"+products.getPrice()+"\t"+products.getCategory_id()); 216 } 217 } 218 }
七.javaBean类
1 public class Products { 2 private Integer pid; 3 private String pname; 4 private double price ; 5 private int category_id; 6 public Integer getPid() { 7 return pid; 8 } 9 public void setPid(Integer pid) { 10 this.pid = pid; 11 } 12 public String getPname() { 13 return pname; 14 } 15 public void setPname(String pname) { 16 this.pname = pname; 17 } 18 public double getPrice() { 19 return price; 20 } 21 public void setPrice(double price) { 22 this.price = price; 23 } 24 public int getCategory_id() { 25 return category_id; 26 } 27 public void setCategory_id(Integer category_id) { 28 this.category_id = category_id; 29 } 30 public Products(Integer pid, String pname, double price, int category_id) { 31 super(); 32 this.pid = pid; 33 this.pname = pname; 34 this.price = price; 35 this.category_id = category_id; 36 } 37 @Override 38 public String toString() { 39 return "Products [pid=" + pid + ", pname=" + pname + ", price=" + price + ", category_id=" + category_id + "]"; 40 } 41 public Products() { 42 super(); 43 // TODO Auto-generated constructor stub 44 } 45 46 }
