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import javax.swing.*;import java.awt.*;import java.awt.event.*;import java.io.*;import java.net.*;public class ChatServerSwing extends JFrame { private JTextArea display; private JTextField input; private PrintWriter out; private BufferedReader in; public ChatServerSwing() { setTitle("서버 채팅"); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // 채팅 화..
package infinityArray; public class Test { public static void main(String[] args) { int[] arr1 = {1,2,3,4,5}; int[] arr2 = new int[10]; for(int i=0; i
package generic; public class GenericMethodTest2 { public static void printArray(T[] array) { for(T element : array) { System.out.printf("%s ", element); } System.out.println(); } public static void main(String[] args) { // T타입은 객체만 가능하기 때문 Integer[] iArray = {10,20,30,40,50}; Double[] dArray = {1.1,1.2,1.3,1.4,1.5}; Character[] cArray = {'K','O','R','E','A'}; printArray(iArray); printArray(dArr..
package generic; public class ThreeDPrinter { private Object material; //Object는 모든 클래스의 조상이다 public void setMaterial(Object material) { this.material = material; } public Object getMaterial() { return material; } @Override public String toString() { return "재료는"+ material ; } } package generic; public class Powder extends Material{ public void doPrinting() { System.out.println("Powder 재료로 출력합니..
package generic; import java.util.ArrayList; public class BoxTest { public static void main(String[] args) { ArrayList list = new ArrayList(); Box b= new Box(); //안에는 객체자료형만 들어갈수있다. b.setData("Hello"); //String s = (String)b.getData(); String s = b.getData(); //제네릭을 쓰면 형변환을 안해도된다. System.out.println(s); Box b1 = new Box(); Integer n = 10; //int 객체자료형은 Integer b1.setData(n); System.out.println(n)..
package io2; import java.io.BufferedOutputStream; import java.io.FileOutputStream; public class BufferedOutputStreamTest { public static void main(String[] args) throws Exception{ //파일을 인수로 FileOutputStream 객체를 생성하고 FileOutputStream fos = new FileOutputStream("alpha.txt"); //그 객체를 인수로 BufferdOutputStream 객체를 생성한다. BufferedOutputStream bos = new BufferedOutputStream(fos); //a~z까지 문자를 기록한다. 버퍼를 사용..
package dateex; public class MyDate { private int year; private int month; private int day; public MyDate() {} public MyDate(int year, int month, int day) { this.setDate(year, month, day); } public void setDate(int year, int month, int day) { if(validYear(year)) { this.year = year; }else { System.err.println("년 범위 초과"); return; } if(validMonth(month)) { this.month = month; }else { System.err.pri..
package db; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.ArrayList; import vo.Table; public class DBtest_select3 { public static void main(String[] args) { String driver = "org.mariadb.jdbc.Driver"; String url = "jdbc:mariadb://localhost:3306/mydb"; String user = "root"; String pw =..
package day09; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.Set; public class MapTest { public static void main(String[] args) { Map map = new HashMap(); map.put("사과", "apple"); map.put("바나나", "banana"); map.put("복숭아", "peach"); String value = map.get("사과"); System.out.println(value); Set keys = map.keySet(); //키들의 집합, 키는 중복이 안되기때문에 Set으로 바꿀 수 있다. S..
package day09; import java.util.Set; import java.util.TreeSet; public class SetTest3 { public static void main(String[] args) { Set set = new TreeSet(); set.add("bbb"); set.add("ccc"); set.add("ddd"); set.add("eee"); set.add("aaa"); System.out.println(set); String[] sArr = new String[5]; set.toArray(sArr); for(int i=0; i
