Spring 声明式事务管理（11）
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案例分析
本案例是图书管理系统精简部分，在数据库中有3张表。分别保存图书库存、图书信息和用户信息。下面是建表SQL语句
1 DROP TABLE IF EXISTS store;
2 DROP TABLE IF EXISTS book ;
3 DROP TABLE IF EXISTS user;
4
5 -- 图书表
6 CREATE TABLE book(
7 sn VARCHAR(20) PRIMARY KEY , -- 图书编码
8 name VARCHAR(20) NOT NULL, -- 图书名称
9 price NUMERIC(9,2) NOT NULL -- 图书价格
10 );
11
12 -- 仓库表
13 CREATE TABLE store(
14 sn VARCHAR(20), -- 图书编码
15 stock INT(9) NOT NULL, -- 图书库存
16 CONSTRAINT fk_sn FOREIGN KEY (sn) REFERENCES book(sn)
17 );
18
19 -- 用户表
20 CREATE TABLE user(
21 id INT(11) PRIMARY KEY AUTO_INCREMENT, -- id
22 name VARCHAR(20) NOT NULL, -- 姓名
23 balance NUMERIC(9,2) NOT NULL DEFAULT 0 -- 余额
24 );
25
26 INSERT INTO book VALUES (\'1001\',\'Java从入门到精通\',100);
27 INSERT INTO book VALUES (\'1002\',\'Spring从入门到精通\',90);
28 INSERT INTO book VALUES (\'1003\',\'J2EE核心框架\',80);
29
30 INSERT INTO store VALUES (\'1001\',50);
31 INSERT INTO store VALUES (\'1002\',20);
32 INSERT INTO store VALUES (\'1003\',10);
33
34 INSERT INTO user (name,balance) VALUES (\'caoyc\',150);
实体类
Book.java
1 package com.proc.bean;
2
3 public class Book {
4
5 private String sn;
6 private String name;
7 private Double price;
8
9 public String getSn() {
10 return sn;
11 }
12
13 public void setSn(String sn) {
14 this.sn = sn;
15 }
16
17 public String getName() {
18 return name;
19 }
20
21 public void setName(String name) {
22 this.name = name;
23 }
24
25 public Double getPrice() {
26 return price;
27 }
28
29 public void setPrice(Double price) {
30 this.price = price;
31 }
32
33 public String toString() {
34 return "Book [sn=" + sn + ", name=" + name + ", price=" + price + "]";
35 }
36
37 }
Store.java
1 package com.proc.bean;
2
3 /**仓库类*/
4 public class Store {
5
6 private String sn;
7 private Integer stock;
8 public String getSn() {
9 return sn;
10 }
11 public void setSn(String sn) {
12 this.sn = sn;
13 }
14 public Integer getStock() {
15 return stock;
16 }
17 public void setStock(Integer stock) {
18 this.stock = stock;
19 }
20 @Override
21 public String toString() {
22 return "Store [sn=" + sn + ", stock=" + stock + "]";
23 }
24
25
26 }
User.java
1 package com.proc.bean;
2
3 /**
4 * @author caoyc
5 *
6 */
7 public class User {
8
9 private Integer id;
10 private String name;
11 private Double balance;
12 public Integer getId() {
13 return id;
14 }
15 public void setId(Integer id) {
16 this.id = id;
17 }
18 public String getName() {
19 return name;
20 }
21 public void setName(String name) {
22 this.name = name;
23 }
24 public Double getBalance() {
25 return balance;
26 }
27 public void setBalance(Double balance) {
28 this.balance = balance;
29 }
30 @Override
31 public String toString() {
32 return "User [id=" + id + ", name=" + name + ", balance=" + balance
33 + "]";
34 }
35
36
37 }
Spring配置信息
使用db.properties记录数据库配置信息，这样便于后期维护
1 jdbc.user=root
2 jdbc.password=123456
3 jdbc.driverClass=com.mysql.jdbc.Driver
4 jdbc.jdbcUrl=jdbc\\:mysql\\:///test
配置applicationContext.xml信息
1 <!-- 配置自动扫描策略 -->
2 <context:component-scan base-package="com.proc"/>
3
4 <!-- 读取db.properties配置信息 -->
5 <context:property-placeholder location="classpath:db.properties"/>
6
7 <!-- 配置一个C3P0数据源 -->
8 <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
9 <property name="user" value="${jdbc.user}"/>
10 <property name="password" value="${jdbc.password}"/>
11 <property name="driverClass" value="${jdbc.driverClass}"/>
12 <property name="jdbcUrl" value="${jdbc.jdbcUrl}"/>
13 </bean>
14
15 <!-- 配置一个JdbcTemplate，用来操作数据库 -->
16 <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
17 <property name="dataSource" ref="dataSource"/>
18 </bean>
这里我们使用自动扫描策略，使用的是C3P0连接池。同时使用了Spring内置的jdbc封装类JdbcTemplate
数据访问层
Java代码：BookDao.java
1 package com.proc.dao;
2
3 import org.springframework.beans.factory.annotation.Autowired;
4 import org.springframework.jdbc.core.BeanPropertyRowMapper;
5 import org.springframework.jdbc.core.JdbcTemplate;
6 import org.springframework.jdbc.core.RowMapper;
7 import org.springframework.stereotype.Repository;
8
9 import com.proc.bean.Book;
10
11 /**图书Dao*/
12 @Repository
13 public class BookDao {
14
15 @Autowired
16 private JdbcTemplate jdbcTemplate;
17
18 /**通过图书编号获取图书信息*/
19 public Book get(String sn){
20
21 String sql="SELECT * FROM book WHERE sn=?";
22 RowMapper<Book> rowMapper=new BeanPropertyRowMapper<Book>(Book.class);
23 Book book=jdbcTemplate.queryForObject(sql, rowMapper,sn);
24 return book;
25 }
26 }
StoreDao
1 package com.proc.dao;
2
3 import org.springframework.beans.factory.annotation.Autowired;
4 import org.springframework.jdbc.core.BeanPropertyRowMapper;
5 import org.springframework.jdbc.core.JdbcTemplate;
6 import org.springframework.jdbc.core.RowMapper;
7 import org.springframework.stereotype.Repository;
8
9 import com.proc.bean.Store;
10
11 /**图书仓库Dao*/
12 @Repository
13 public class StoreDao {
14
15 @Autowired
16 private JdbcTemplate jdbcTemplate;
17
18 /**通过图书编号获取图书库存信息*/
19 public Store get(String sn){
20 String sql="SELECT * FROM store WHERE sn=?";
21 RowMapper<Store> rowMapper=new BeanPropertyRowMapper<Store>(Store.class);
22 Store store=jdbcTemplate.queryForObject(sql, rowMapper,sn);
23 return store;
24 }
25
26 /**通过图书编号，修改图书库存 库存=当前库存-1*/
27 public void update(String sn){
28 String sql="UPDATE store SET stock=stock-1 WHERE sn=?";
29 jdbcTemplate.update(sql, sn);
30 }
31 }
UserDao.java
1 package com.proc.dao;
2
3 import org.springframework.beans.factory.annotation.Autowired;
4 import org.springframework.jdbc.core.BeanPropertyRowMapper;
5 import org.springframework.jdbc.core.JdbcTemplate;
6 import org.springframework.jdbc.core.RowMapper;
7 import org.springframework.stereotype.Repository;
8
9 import com.proc.bean.User;
10
11 /**用户Dao*/
12 @Repository
13 public class UserDao {
14
15 @Autowired
16 private JdbcTemplate jdbcTemplate;
17
18 /**通过用户ID获取用户信息*/
19 public User get(Integer id){
20 String sql="SELECT * FROM user WHERE id=?";
21 RowMapper<User> rowMapper=new BeanPropertyRowMapper<User>(User.class);
22 User user=jdbcTemplate.queryForObject(sql, rowMapper,id);
23 return user;
24 }
25
26 /**修改用户余额*/
27 public void update(Integer id,Double price){
28 String sql="UPDATE user SET balance=balance-? WHERE id=?";
29 jdbcTemplate.update(sql, new Object[]{price,id});
30 }
31 }
这里为每个Dao都注入了一个JdbcTemplate的实例，可以使用JDBC方式操作数据库
异常处理
考虑到有可能会出现用户余额或图书库存不足的情况，这里我们自定义了两个异常
1、库存不足异常类：
1 package com.proc.exception;
2
3 public class BookStockException extends RuntimeException{
4 public BookStockException(String msg) {
5 super(msg);
6 }
7 }
2、余额不足异常类
1 package com.proc.exception;
2
3 public class UserBalanceException extends RuntimeException {
4 public UserBalanceException(String msg) {
5 super(msg);
6 }
7 }
逻辑业务层
1、定义一个接口
1 package com.proc.service;
2
3 public interface BookShopService {
4
5 /**
6 * 购买图书
7 * @param userId 购买用户ID
8 * @param sn 图书编号
9 */
10 void purchase(Integer userId,String sn);
11 }
2、定义一个BookShopService借口实现类
1 package com.proc.service;
2
3 import org.springframework.beans.factory.annotation.Autowired;
4 import org.springframework.stereotype.Service;
5 import org.springframework.transaction.annotation.Transactional;
6
7 import com.proc.bean.Book;
8 import com.proc.bean.Store;
9 import com.proc.bean.User;
10 import com.proc.dao.BookDao;
11 import com.proc.dao.StoreDao;
12 import com.proc.dao.UserDao;
13 import com.proc.exception.BookStockException;
14 import com.proc.exception.UserBalanceException;
15
16 @Service("bookShopService")
17 public class BookShopServiceJdbcImps implements BookShopService{
18
19 @Autowired
20 private UserDao userDao;
21 @Autowired
22 private BookDao bookDao;
23 @Autowired
24 private StoreDao storeDao;
25
26
27 /**购买图书方法*/
28 public void purchase(Integer userId, String sn) {
29
30 //1:查收出图库存信息
31 Store store= storeDao.get(sn);
32 if(store.getStock()<=0){
33 throw new BookStockException("图书库存不足："+store);
34 }
35
36 //2:查询图书信息
37 Book book=bookDao.get(sn);
38
39
40 //3:查询用户信息
41 User user=userDao.get(userId);
42 if(user.getBalance()<book.getPrice()){
43 throw new UserBalanceException("用户余额不足："+user);
44 }
45
46 //4:修改库存
47 storeDao.update(sn);
48
49 //5:修改余额
50 userDao.update(userId, book.getPrice());
51 }
52
53 }
测试代码：
1 package com.proc.test;
2
3 import org.junit.Test;
4 import org.springframework.context.ApplicationContext;
5 import org.springframework.context.support.ClassPathXmlApplicationContext;
6
7 import com.proc.service.BookShopService;
8
9 public class TestShopBook {
10
11 private ApplicationContext ctx;
12 private BookShopService bookShopService;
13 {
14 ctx=new ClassPathXmlApplicationContext("applicationContext.xml");
15 bookShopService=(BookShopService) ctx.getBean("bookShopService");
16 }
17
18 @Test
19 public void purchase(){
20
21 bookShopService.purchase(1, "1001");
22 }
23 }
第一次执行：
Spring基础：声明式事务