java tutorial 1 2004/10/21. java resource java sdk –download from :// –install...
TRANSCRIPT
Java Tutorial 1
2004/10/21
Java Resource• Java SDK
– Download from http://www.javasoft.com– Install
• Jdk-1.5.0-windows-i586.exe
– 設定環境變數• Set classpath=c:\program files\java\jdk-1.5.0\lib\too
ls.jar;c;\example\lib\example.jar;.• Set Path=c:\program files\java\jdk-1.5.0
– 測試• Java• Javac
Java Program
• Require– Program Editor
• Notepad• UltraEdit• 可以編輯文字的編輯器都可以
– 檔案名稱需要與 Class 名稱相同 ( 注意大小寫 )– 副檔名需儲存為 .java– J2SE 5.0 Documentation
• Java 2 Platform API Specification
Example
• Like C Example---------------------------------------------------------------public class forLoop {
public static void main(String args[]) {for (int count=0;count<10;count++) {
Systm.out.println (“count=“+count);}
}
}---------------------------------------------------------------
Example(1)
• forLoop.java– Class name is “forLoop”,
將 forLoop class 儲存成 forLoop.java– public static void main(args[])
是程式執行的進入點– for (int count=0;count<10;count++) {
• 需要使用變數時才宣告• Compile
– Javac forLoop.java– 產生 forLoop.class 的可執行 byte code
• Run– Java forLoop
Java Example(2)
public class forLoop2 {public static void main(String args[]) {
for (int count=0;count<10;count++) {Systm.out.println (“count=“+count);
}System.out.println (“”);for (int count=0;count<10;count++) {
Systm.out.println (“count=“+count);}
}
}– Save class as “forLoop2.java”
Java Standard Output
• System.out– System.out.print();– System.out.println();
• System.out.printf()– J2SE 5.0 支援 , 可寫跟 C 一樣的 printf 方式
輸出
Java Input
public class JavaInput {public static void main(String args[]) {
If (args.length>0) {System.out.println (args[0]);System.out.println (args[1]);System.out.println (args[2]);
}
}}• Java 使用 args 陣列來接收外部的輸入參數
– Javac JavaInput.java– Java JavaInput I am here
• 輸出 I am here• 小於三個輸入會有錯誤
Course Examplepublic class StringMatch {
private String source;public void match(String taget) {
for (int count=0;count<source.length();count++) {If (target.equals(source.substring(count,count+target.length()) {
System.out.println (target);}
}
}public void setSource(String source) {
this.source=source;
}public static void main(String args[]) {
StringMatch stm=new StringMatch();stm.setSource(“abcabcabcabc”);stm.match(“cab”);
}
}
Course Example(2)public class StringMatch {
private String source;public void match(String taget) {
for (int count=0;count<source.length();count++) {If (target.equals(source.substring(count,count+target.length()) {
System.out.println (target);}
}
}public void setSource(String source) {
this.source=source;
}public static void main(String args[]) {
StringMatch stm=new StringMatch();stm.setSource(“abcabcabcabc”);stm.match(args[0]);
}
}