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 }
原文地址：https://www.cnblogs.com/xuzhaocai/p/8215730.html
时间： 2024-11-07 17:04:25