append() ã¯ãçŸåšã®ã·ãŒã±ã³ã¹ã«å€ã远å ãã StringBuilder ã¯ã©ã¹ããã³ StringBuffer ã¯ã©ã¹ã® Java ã¡ãœããã§ããappend()ã¡ãœãããäœã§ãããç¥ããªãã£ããšããŠãããããããã§ã«æé»çã«ããã䜿çšããŠããã§ããããããã¯ãJava ã§ + æŒç®åã䜿çšããŠæååãé£çµãããšãã«çºçããŸãããéèŠãªã®ã¯ãJava ã® String é£çµã¯ StringBuilder ãŸã㯠StringBuffer ã¯ã©ã¹ãšãã®append()ã¡ãœããã䜿çšããŠå®è£
ããããšããããšã§ãã
StringãStringBufferãStringBuilder ã«ã€ããŠç°¡åã«èª¬æããŸãã
ãããããåç¥ã®ãšãããString ã¯ã©ã¹ã¯ Final (åã¯ã©ã¹ãæããªã) ã§ãããäžå€ (ãã®ã¯ã©ã¹ã®ã€ã³ã¹ã¿ã³ã¹ã¯äœæåŸã«å€æŽã§ããŸãã) ã§ããå®éãString ã¯ã©ã¹ã®äžå€æ§ã«ãããåæäœã®çµæãšããŠæ°ããæååã€ã³ã¹ã¿ã³ã¹ãäœæãããå€ãæååã€ã³ã¹ã¿ã³ã¹ã¯ç Žæ£ããã倧éã®ã¬ããŒãžãçæãããŸããString ãªããžã§ã¯ãã®å€æŽã«ããäžæçãªã¬ããŒãžã®çæã«å¯ŸåŠããã«ã¯ãStringBuffer ã¯ã©ã¹ãŸã㯠StringBuilder ã¯ã©ã¹ã䜿çšã§ããŸããåŸè ã® 2 ã€ã®äž»ãªéãã¯ãStringBuffer ã¯åæãããã®ã«å¯ŸããStringBuilder ã¯åæãããªãããšã§ãããããã£ãŠããã«ãã¹ã¬ããç°å¢ã§é »ç¹ã«å€æŽãããæååã«ã¯ StringBuffer ã䜿çšããã·ã³ã°ã«ã¹ã¬ããç°å¢ã®å Žå㯠StringBuilder ã䜿çšããŸãã
StringBuilder ããã³ StringBuffer ã® Append()
append() ã¯ãStringBuilder ã¯ã©ã¹ãš StringBuffer ã¯ã©ã¹ã®æäžäœã¡ãœããã® 1 ã€ã§ããçŸåšã®ã·ãŒã±ã³ã¹ã«æ°ããå€ã远å ããŸããStringBuffer ã¯ã©ã¹ãš StringBuilder ã¯ã©ã¹ã®äž¡æ¹ã«ã 13 åã®ããŸããŸãªãªãŒããŒããŒããããappend()ã¡ãœããããããŸããStringBuilder ã® append ã¡ãœãããèŠãŠã¿ãŸãããããšã«ãããStringBuffer ã®å Žåã§ããŸã£ããåãããã«æ©èœããŸãã- public StringBuilder append(boolean b)
- public StringBuilder append(char c)
- public StringBuilder append(char[] str)
- public StringBuilder append(char[] str, int offset, int len)
- public StringBuilder append(CharSequence cs)
- public StringBuilder append(CharSequence cs, int start, int end)
- public StringBuilder append(double d)
- public StringBuilder append(float f)
- public StringBuilder append(int i)
- public StringBuilder append(long lng)
- public StringBuilder append(Object obj)
- public StringBuilder append(String str)
- public StringBuilder append(StringBuffer sb)
Java.lang.StringBuilder.append(int i)
java.lang.StringBuilder.append(int i) ã¯ãæ¢åã® StringBuilder ãªããžã§ã¯ãã«æŽæ°ã远å ã§ããããã«ããã¡ãœããã§ããJava.lang.StringBuilder.append(int i)ã®äœ¿çšäŸãèŠãŠã¿ãŸãããã
StringBuilder s = new StringBuilder(âI love Java â);
int i = 14;
//the method appends StringBuilder and integer
s.append(i);
System.out.println(s);
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Java 14 ã倧奜ãã§ã
ããã§äœãèµ·ãã£ãã®ã§ããããïŒãŸããå€ãI love Javaããæã€ s ãšããååã® StringBuilder ãäœæããŸãããæ¬¡ã«ã append(int)ã䜿çšããŠæŽæ° 14 ã远å ããŸããå³å¯ã«èšãã°ãæŽæ°ã§ã¯ãªãæååã14ãã远å ãããI love Java 14ãã«æŽæ°ããã StringBuilder å€ãååŸããŸããããããã£ãŠããã®ã¡ãœããã¯åŒæ°ã StringBuilder ãªããžã§ã¯ãã«å€æãããããæ¢åã® StringBuilder ãªããžã§ã¯ãã«ãã€ã³ãããæŽæ°ããããªããžã§ã¯ããè¿ããŸãã
Objectãintãbooleanãããã³ String åŒæ°ã® StringBuilder append() ã®äŸ
æ°å€ãæååãæåããŸãã¯é åèŠçŽ ãå«ãä»ã®ãã¹ãŠã®ãªãŒããŒããŒããããã¡ãœããã«ã€ããŠããåãããšãèšããŸããLegoBrick ã¯ã©ã¹ãš Color åæåãäœæããŠããããªãã¯StringBuilder append(Object obj)ã¡ãœããããã¢ããŸãããã
//enum with colors
public enum Color {
RED, YELLOW, BLUE;
}
//LegoBrick Class code
public class LegoBrick {
Color color;
boolean isConnected;
public void connect() {
System.out.println("This brick is connected");
this.isConnected = true;
}
public void disconnect() {
System.out.println("Disconnected");
isConnected = false;
}
public LegoBrick(Color color, boolean isConnected) {
this.color = color;
this.isConnected = isConnected;
}
public Color getColor() {
return color;
}
public boolean isConnected() {
return isConnected;
}
@Override
public String toString() {
return "LegoBrick{" +
"color=" + color +
", isConnected=" + isConnected +
'}';
}
}
次ã«ãStringãintãLegoBrickãããã³ boolean ã䜿çšããåºæ¬ç㪠StringBuilder ã®è¿œå ã瀺ã AppendDemo ã¯ã©ã¹ãäœæããŸããããå¥åŠã«èãããŸãããããŸããããŸãã
public class AppendDemo {
public static void main(String[] args) {
StringBuilder s = new StringBuilder("I love");
System.out.println(s)
//the method appends StringBuilder and String
s.append(" Java");
System.out.println(s);
//the method appends StringBuilder and int
s.append(14);
System.out.println(s);
LegoBrick legoBrick = new LegoBrick(Color.RED, false);
//the method appends StringBuilder and LegoBrick
s.append(legoBrick);
System.out.println(s);
//the method appends StringBuilder and boolean
System.out.println(s.append(5<7));
}
}
åºåã¯æ¬¡ã®ãšããã§ãã
Java ã倧奜ãã§ã Java14 ã倧奜ãã§ã Java14LegoBrick{color=RED, isConnected=false} ã倧奜ãã§ã Java14LegoBrick{color=RED, isConnected=false}true ã倧奜ãã§ã
ãŸããStringBuilder "I love" ãäœæããŠè¡šç€ºããæ¬¡ã«append()ã¡ãœããã䜿çšã㊠Stringãint æ°å€ãObject ã® String 衚çŸãããã³ boolean ãé çªã«è¿œå ããŸããã
StringBuilder append(char[] cstrãint ã»ãããint é·)
3 ã€ã®ãã©ã¡ãŒã¿ãæã€append()ã¡ãœãããèŠãŠã¿ãŸããããæå®ããã char é åã®éšåé åã®è¡šçŸãæååã«è¿œå ããŸããããã§:- cstrã¯è¿œå ãããæåã®é åã§ãã
- 远å ããæåã®æåã®ã€ã³ããã¯ã¹ãèšå®ããŸãã
- lengthã¯è¿œå ããæåæ°ã§ãã
public class AppendDemo {
// an example of using append(char[], cStr, int set, int length)
public static void main(String[] args) {
StringBuilder s = new StringBuilder("I love ");
//here is a char's array, part of which we are going to append to s
char[] cStr = new char[]
{'c', 'o', 'd', 'e', 'J', 'a', 'v', 'a', '1', '4'};
//we append 4 elements of cStr from the 4th element "J"
s.append(cStr, 4, 4);
System.out.println(s);
}
}
åºåã¯æ¬¡ã®ãšããã§ãã
ãžã£ã¯ã倧奜ãã§ã
CharSequence åŒæ°ãæã€ StringBuilder append() ã¡ãœãã
åŒæ°ãšã㊠CharSequence ãæã€ 2 ã€ã®ã¡ãœããã«æ°ã¥ãããããããŸããã- public StringBuilder append(CharSequence cs)
- public StringBuilder append(CharSequence cs, int start, int end)
public class CharSequenceDemo {
public static void printCharSequence(CharSequence ch) {
System.out.println(ch);
}
public static void main(String[] args) {
CharSequence myString = new String("This is String ");
printCharSequence(myString);
CharSequence myStringBuilder = new StringBuilder("This is StringBuilder ");
printCharSequence(myStringBuilder);
StringBuilder s = new StringBuilder("my StringBuilder ");
//StringBuilder.append
s.append(myStringBuilder);
System.out.println(s);
//StringBuilder.append
s.append(myString);
System.out.println(s);
s.append(myString, 5,7);
System.out.println(s);
}
}
åºåã¯æ¬¡ã®ãšããã§ãã
ãã㯠String ãã㯠StringBuilder ç§ã® StringBuilder ãã㯠StringBuilder ç§ã® StringBuilder ãã㯠StringBuilder ãã㯠String ç§ã® StringBuilder ãã㯠StringBuilder ãã㯠String ã§ã
2 ã€ã® CharSequence ãäœæããString ãš StringBuilder ããã€ã³ãããŠåºåããŸãããCharSequence ã«ã¯ãã®ã¡ãœããããªãããã append()ã¡ãœããã myStringBuilder ã«çŽæ¥é©çšããããšã¯ã§ããŸãã(çç±ãããããªãå Žåã¯ãåç
§åã®æ¡åŒµãšçž®å°ã ãã§ãªãç¶æ¿ã«ã€ããŠãçè§£ããå¿
èŠããããŸã)ããããã£ãŠãäž¡æ¹ã® CharSequence ã§ StringBuilder ãäœæããappend ã¡ãœããã䜿çšããŠé 次é£çµããŸããæåŸã«ãStringBuilder ã«ãµãã·ãŒã±ã³ã¹ãisãã远å ããŸãã (ãiã㯠myStringBuilder ã® 5 çªç®ã®èŠçŽ ãs 㯠6 çªç®ã®èŠçŽ ã§ãããã®ã¡ãœããã§ã¯ãend ãšããŠæå®ãããèŠçŽ ããµãã·ãŒã±ã³ã¹ããé€å€ãããããšã«æ³šæããŠãã ããã
StringBuffer append() ã¯ã©ãã§ãããã?
StringBuffer.appendã«ã 13 ã®ã¡ãœããã®ããªã¢ã³ãããããããã㯠StringBuilder ãšãŸã£ããåãããã«åäœããŸãã- public StringBuffer 远å (ããŒã«å€ b)
- public StringBuffer append (char c)
- public StringBuffer append (char[] str)
- public StringBuffer append (char[] str, int offset, int len)
- public StringBuffer 远å (double d)
- public StringBuffer 远å (float f)
- public StringBuffer append (int i)
- public StringBuffer 远å (long lng)
- public StringBuffer append (CharSequence s)
- public StringBuffer append (CharSequence s, int start, int end)
- public StringBuffer append (ãªããžã§ã¯ã obj)
- public StringBuffer append (String str)
- public StringBuffer 远å (StringBuffer sb)
public class AppendDemo {
// an example of using append(char[], cStr, int set, int length)
public static void main(String[] args) {
StringBuffer s = new StringBuffer("I love ");
//here is a char's array, part of which we are going to append to s
char[] cStr = new char[]
{'c', 'o', 'd', 'e', 'J', 'a', 'v', 'a', '1', '4'};
//we append 4 elements of cStr from the 4th element "J"
//with StringBuffer.append
s.append(cStr, 4, 4);
System.out.println(s);
//StringBuffer.append adds int 14 to s
s.append(14);
System.out.println(s);
}
}
åºåã¯æ¬¡ã®ãšããã§ãã
Java ã倧奜ã Java14 ã倧奜ã
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