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Course content introduction:
1. Introduction to Spring framework
2. IOC container
2.1 underlying principle of IOC
2.2. IOC interface - BeanFactory
2.3. IOC operation bean management
2.4. There are two ways to manage Bean operations
2.4.1. IOC operation bean management - based on xml (demo01, demo02)
2.4.2. IOC operation bean management - annotation based method (demo03 demo04)
3,AOP
3.1. What is AOP (concept)
3.2 AOP underlying principle
3.3 AOP related terms
3.4 AOP operation preparation
3.5. AOP operation - based on AspectJ annotation
3.6, AOP operation - based on AspectJ configuration file
4,JdbcTemplate
4.1. What is a JdbcTemplate
4.2 preparation
4.3. CRUD based on the preparation of 4.2
5. Transaction management
What is a business
Transaction is the most basic unit of database operation and a logical group of operations,
Either all succeed. If one fails, all operations fail
Typical scene. bank transfer
5.2 four characteristics of transaction ACID
Atomicity: atomicity means that transactions in the database are executed as atomicity. That is, it cannot be divided again. The whole statement is either executed or not executed
Consistency: consistency means that the integrity constraints of the database are not destroyed before and after the transaction.
Isolation: the execution of transactions does not interfere with each other. It is impossible for a transaction to see the data at a certain time when other transactions are running
Persistence: it means that after the transaction is completed, the changes made by the transaction to the database will be permanently saved in the database and will not be rolled back
5.3. Create a new transaction operating environment
Step 1: add records for creating database and table:
stay user_db Create in Library t_account
Step 2: create service，build dao. Complete object creation and injection relationship
stay service Medium injection dao，dao Medium injection jdbcTemplate，stay jdbcTemplate Medium injection DataSource
Step 3. In dao Create two methods, more money and less money, in service Method of creating transfer in
@Repository
public class AccountDaoImpl implements AccountDao{
@Autowired
private JdbcTemplate jdbcTemplate;
@Override
public void addMoney() {
String sql = "update t_account set money=money+? where username=?";
//Set mary to have 100 more money
jdbcTemplate.update(sql, 100,"mary");
}
@Override
public void reduceMoney() {
String sql = "update t_account set money=money-? where username=?";
//The setting makes lucy's money less by 100
jdbcTemplate.update(sql, 100,"lucy");
}
Step 4: write test
@Test
public void test1(){
//Create container to load core configuration file
ApplicationContext context =
new ClassPathXmlApplicationContext("spring1.xml");
//Get object from container
AccountService accountService = context.getBean("accountService", AccountService.class);
//Call method
accountService.accountMoney();
}
Step 5: run to view the database
lucy 100 less mary 100 more
Step 6: simulate abnormal
If there is an exception in the above code
public void accountMoney(){
//100 less luncy
accountDao.reduceMoney();
//Simulated intention
int a = 1/0;
//maey more than 100
accountDao.addMoney();
}
The results are: lucy 100 less, but mary No increase of 100
Step 7. Use transaction to resolve the exception
//Method of transfer
public void accountMoney(){
try{
//Step 1: start the transaction
//Step 2: process business
//100 less luncy
accountDao.reduceMoney();
//Simulated intention
int a = 1/0;
//maey more than 100
accountDao.addMoney();
//Step 3: if no exception occurs, the transaction is committed
}catch(Exception e){
//Step 4: if an exception occurs, the transaction is rolled back
}
}
5.4. Spring transaction management operation
5.4.1. Add transactions to the Service layer in the three-tier architecture of Java EE, that is, the business logic layer
5.4.2. Transaction management in Spring - two methods
Transaction during programming: not recommended, the code is bloated and difficult to maintain
Declarative transaction: easy to use
5.4.3 declarative transaction:
1,Annotation based approach
2,be based on xml Profile mode
3,stay Spring Declarative transaction management. The bottom layer is used AOP principle
4,An interface can be provided to represent the transaction manager. This interface provides different implementation classes for different frameworks