Java

Basic

기본 연산, 제어 구조
산술 연산, 논리 연산
자료형; 기본자료형, 참조형, 인스턴스, 래퍼클래스, 상수
비교 연산; 주요 비교 연산자, 참조형 비교, String 비교, 자료형 비교(instanceof 연산자), 논리 연산
조건 분기; if, switch, for, while, do-while, break, continue, return
객체지향
- 캡슐화
- 상속
- 생성자
- 다형성
- 인터페이스
- 위임
제네릭
람다식

Preparing

개발환경 구성
- JDK
- IDE 혹은 TextEditor
- Build 도구 (Maven, Gradle) 및 의존성관리
- 기타 개발 도구

Examples

String → StringBuilder

java.util.Date ↔ java.time.Instant
java.util.Calendar → java.time.Instant
java.text.SimpleDateFormat
java.time
- Local
- Zoned
- Offset
Collections
- List; ArrayList, LinkedList
- Set; HashSet, LinkedHashSet
- Map; HashMap, LinkedHashMap

람다식

(자료형 인수, ...) -> { ... 임의의 처리 ...}

Database

import java.sql.*;

...
...
  Connection conn = null;
  
  try
  {
    Class.forName("DRIVER");
  }
  catch(ClassNotFoundException e)
  {
    e.printStackTrace();
  }
  
  try
  {
    conn = DriverManager.getConnection("jdbc database", "user", "password");
    
    Statement stmt = conn.createStatement();
    ResultSet rset = stmt.executeQuery("QUERY");
    
    while(rset.next())
    {
      // do something
    }
  }
  catch(SQLException e)
  {
    e.printStackTrace();
  }
  finally
  {
    if(conn != null)
    {
      try
      {
        conn.close();
        conn = null;
      }
      catch(SQLException e)
      {
        e.printStackTrace();
      }
    }
  }
  
...
...

conn.setAutoCommit(true/false);
conn.commit();
conn.rollback()
PreparedStatement stmt = conn.prepareStatement(“…. ?”);
- stmt.setString(1, “value”);

DAO^{Data Access Object}
DTO^{Data Transfer Object}
JPA^{Java Persistence API}

File I/O

FileReader
BufferedReader
Scanner
Files

CSV, XML, LOGGER

Tests

JUint
- @Test
- @Before
- @After
- @BeforeClass
- @AfterClass
- @Ignore
- import static org.junit.Assert.*;
  - assertEquals()
  - fail()
  - assertThat()
  - import static org.hamcrest.CoreMatchers.*;
    - is()
JMockit
DbUnit

Reserved Words

data types <list-group>
byte
short
int
long
float
double
char
boolean
void

</list-group>

class & packages <list-group>
class
interface
enum
package
import
extends
implements
this
super
new

</list-group>

modifiers <list-group>
public
protected
private
static
final
abstract
native
volatile
transient
synchronized
strictfp

</list-group>

operations <list-group>
if
else
switch
case
default
for
while
do
break
continue
return
instanceof
assert

</list-group>

exceptions <list-group>
try
catch
finally
throw
throws

</list-group>

others <list-group>
const
goto

</list-group>

reth

Table of Contents

Java

Basic

Preparing

Examples

Database

File I/O

Tests

Reserved Words

References