Java with notes (iii)

Altogether three groups:
Vector (1.0)--arraylist (1.2)
HashTable (1.0)--hashmap (1.2)
StringBuffer (1.0)--stringbuilder (1.5) Extend Abstractstringbuilder

Checked exception
External resource problems, the JVM can foresee such as: the read file does not exist, the database connection is not established, etc.

Unchecked Exception (runtimeexcepeion)
Programmer coding Problem caused by

Responsibility chain Model


Handling Exceptions in blocks
Return takes the finally as the subject


Three-tier architecture:
User interface----、 GUI, page, presentation layer
|
|
Service---business logic layer
|
|
DAO---Data access layer (JDBC encapsulation)
DB----Database (SQL)


Dto--data Transfan Object (VO)---Data transfer objects, anemia objects: Only attributes have no behavior

Stored procedures in the database are not portable
CallableStatement extends Prestatement interface
CallableStatement Proc=null;
Proc=conn.preparecall ("{Call TESTB (?,?)}");
Proc.setint (1,8888);
Proc.setstring (2,type.varchar);

Java with notes (iii)