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📜  Java中的 StringBuilder append() 方法及示例

📅  最后修改于: 2022-05-13 01:54:32.767000             🧑  作者: Mango

Java中的 StringBuilder append() 方法及示例

Java.lang.StringBuilder.append()方法用于将某个参数的字符串表示附加到序列中。有 13 种方式/形式可以通过传递各种类型的参数来使用 append() 方法：

  1. StringBuilder append( boolean a ) : Java.lang.StringBuilder.append( boolean a ) 是Java中的一个内置方法，用于将布尔参数的字符串表示形式附加到给定序列。

    句法 ： 

    public StringBuilder append(boolean a)

    参数：此方法接受布尔类型的单个参数a并引用要附加的布尔值。

    返回值：该方法返回对该对象的引用。

    例子： 

    Input: 
string_buffer = "We are Indians" 
boolean a = true

Output: We are Indians true

    下面的程序说明了Java.lang.StringBuilder.append() 方法： 

    // Java program to illustrate the
// StringBuilder append(boolean a)
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        StringBuilder sb1 = new 
                      StringBuilder("Welcome to Geeksforgeeks ");
        System.out.println("Input: " + sb1);
  
        // Appending the boolean value
        sb1.append(true);
        System.out.println("Output: " + sb1);
  
        System.out.println();
  
        StringBuilder sb2 = new StringBuilder("We fail- ");
        System.out.println("Input: " + sb2);
  
        // Appending the boolean value
        sb2.append(false);
        System.out.println("Output: " + sb2);
    }
}
    输出： 
    Input: Welcome to Geeksforgeeks 
Output: Welcome to Geeksforgeeks true

Input: We fail- 
Output: We fail- false
  2. Java.lang.StringBuilder.append( char a )：这是Java中的一个内置方法，用于将 char 参数的字符串表示形式附加到给定的序列中。 char 参数附加到此 StringBuilder 序列的内容中。

    句法 ： 

    public StringBuilder append(char a)

    参数：该方法接受单个参数a ，它是要附加其字符串表示的 Char 值。

    返回值：该方法执行追加操作后返回一个字符串对象。
    例子 ： 

    Input :
StringBuilder = I love my Country 
char a = A

Output: I love my Country A

    下面的程序说明了Java.lang.StringBuilder.append(char a) 方法。 

    // Java program to illustrate the
// java.lang.StringBuilder.append(char a)
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
          
        StringBuilder sbf = new 
                       StringBuilder("Welcome geeks!");
                System.out.println( sbf);
  
        /* Here it appends the char argument as
        string to the StringBuilder */
        sbf.append('T');
        System.out.println("Result after"+
                                 " appending = " + sbf);
  
      
        sbf = new StringBuilder("hello world-");
                System.out.println(sbf);
        /* Here it appends the char argument as
        string to the String Builder */
        sbf.append('#');
        System.out.println("Result after appending = " 
                                                         + sbf);
    }
}
    输出： 
    Welcome geeks!
Result after appending = Welcome geeks!T
hello world-
Result after appending = hello world-#
  3. StringBuilder append( char[] asr )： Java.lang.StringBuilder.append( char[] asr ) 是内置方法，它将 char 数组参数的字符串表示附加到此 StringBuilder 序列。

    句法 ： 

    public StringBuilder append(char[] astr)

    参数：该方法接受单个参数asr ，这是要附加其字符串表示的 Char 序列。

    返回值：该方法执行追加操作后返回一个字符串对象。
    例子： 

    Input :
StringBuffer  = I love my Country   
char[] astr = 'I', 'N', 'D', 'I', 'A'

Output: I love my Country INDIA

    下面的程序说明了Java.lang.StringBuilder.append( char[] asr ) 方法： 

    // Java program to illustrate the
// java.lang.StringBuilder.append(char[] astr)
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
          
        StringBuilder sbf = new 
                      StringBuilder("We are geeks  ");
        System.out.println(sbf);
  
        // Char array
        char[] astr = new char[] 
                          { 'G', 'E', 'E', 'k', 'S' };
  
        /* Appends string representation of char
                   array to this String Builder */
        sbf.append(astr);
    System.out.println("Result after"+
                            " appending = " + sbf);
          
        sbf = new StringBuilder("We are  -");
                System.out.println(sbf);
  
        // Char array
        astr = new char[] { 'a', 'b', 'c', 'd' };
  
        /* Appends string representation of char 
                   array to this StringBuilder */
        sbf.append(astr);
        System.out.println("Result after appending = " + sbf);
    }
}
    输出： 
    We are geeks  
Result after appending = We are geeks  GEEkS
We are  -
Result after appending = We are  -abcd
  4. StringBuilder append( char[] cstr, int iset, int ilength ) ：此方法将 char 数组参数的子数组的字符串表示附加到此序列。从索引 iset 开始的 char 数组 cstr 的字符按顺序附加到此序列的内容中。这个序列的长度增加了 ilength 的值。

    句法 ： 

    public StringBuilder append(char[] cstr, int iset, int ilenght)

    参数：此方法接受三个参数：

    • cstr – 这是指 Char 序列。
    • iset – 这是指要附加的第一个字符的索引。
    • ilenght – 这是指要附加的字符数。

    返回值：该方法执行追加操作后返回一个字符串对象。
    下面的程序说明了Java.lang.StringBuilder.append(char[] cstr, int iset, int ilength) 方法。 

    // Java program to illustrate the
// append(char[] cstr, int iset, int ilength)
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        StringBuilder sb = new 
                              StringBuilder("Geeks");
        System.out.println("String Builder "+
                                   "before = " + sb);
  
        char[] cstr = new char[] 
          { 'f', 'o', 'r', 'G', 'e', 'e', 'k', 's','q','q' };
  
        /* appends the string representation of char array 
           argument to this String Builder with offset initially 
           at index 0 and length as 8 */
        sb.append(cstr, 0, 8);
  
        // Print the String Builder after appending
        System.out.println("After appending String Builder = " + sb);
    }
}
    输出： 
    String Builder before = Geeks
After appending String Builder = GeeksforGeeks
  5. StringBuilder append( double a )：此方法只是将 double 参数的字符串表示形式附加到此 StringBuilder 序列。

    句法 ： 

    public StringBuilder append(double val)

    参数：该方法接受单个参数val ，该参数指的是要附加其字符串表示的十进制值。

    返回值：该方法执行追加操作后返回一个字符串对象。
    例子 ： 

    Input :
StringBuffer = my Country
Double a = 54.82

Output: my Country 54.82

    下面的程序说明了Java.lang.StringBuilder.append(double val) 方法。 

    // Java program to illustrate the
// java.lang.StringBuilder.append()
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        System.out.println("We are geeks and its really ");
        StringBuilder sbf = new 
              StringBuilder("We are geeks and its ");
  
        // Char array
        Double astr = new Double(36.47);
  
        /* Here it appends string representation of Double 
           argument to this StringBuilder*/
        sbf.append(astr);
        System.out.println("Result after appending = " + sbf);
  
        System.out.println("We are lost -");
        sbf = new StringBuilder("We are lost -");
  
        astr = new Double(27.38);
  
        /* Here it appends string representation of Double  
           argument to this StringBuilder*/
        sbf.append(astr);
        System.out.println("Result after appending = " + sbf);
    }
}
    输出： 
    We are geeks and its really 
Result after appending = We are geeks and its 36.47
We are lost -
Result after appending = We are lost -27.38
  6. StringBuilder append( float val )：此方法将浮点参数的字符串表示附加到此序列。

    句法 ： 

    public StringBuilder append(float val)

    参数：该方法接受单个参数val ，该参数是要附加其字符串表示的浮点值。

    返回值： StringBuilder.append( float val ) 方法在执行操作后返回对字符串对象的引用。

    例子 ： 

    Input : 
StringBuilder  = I love my Country 
float a = 5.2
 
Output: I love my Country 5.2

    下面的程序说明了Java.lang.StringBuilder.append() 方法。 

    // Java program to illustrate the
// java.lang.StringBuilder.append()
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        System.out.println("We are geeks and its really ");
        StringBuilder sbf = new 
                    StringBuilder("We are geeks and its ");
  
        Float astr = new Float(6.47);
  
        /* Here it appends string representation of 
           Float argument to this StringBuilder */
        sbf.append(astr);
        System.out.println("Result after appending = "+sbf);
  
        System.out.println("We are lost -");
        sbf = new StringBuilder("We are lost -");
  
        astr = new Float(27.38);
  
        // Here it appends string representation of Float
        // argument to this String Builder
        sbf.append(astr);
        System.out.println("Result after appending = "+sbf);
    }
}
    输出： 
    We are geeks and its really 
Result after appending = We are geeks and its 6.47
We are lost -
Result after appending = We are lost -27.38
  7. StringBuilder append( int val )此方法只是将 int 参数的字符串表示形式附加到此 StringBuilder 序列。
    句法 ： 
    public StringBuilder append(int val)

    参数：该方法接受单个参数val ，该参数是一个整数值，应该对其执行操作。

    返回值：该方法返回对该对象的引用。

    例子 ： 

    Input :
StringBuilder = I love my Country  
int a = 55

Output: I love my Country 55

    下面的程序说明了Java.lang.StringBuilder.append() 方法。 

    // Java program to illustrate the
// java.lang.StringBuilder.append()
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        System.out.println("We are geeks and its really ");
        StringBuilder sbf = new 
                    StringBuilder("We are geeks and its ");
  
        Integer astr = new Integer(827);
  
        /* Here it appends string representation of 
           Integer argument to this StringBuilder*/
        sbf.append(astr);
        System.out.println("Result after appending = "+sbf);
  
        System.out.println("We are lost -");
        sbf = new StringBuilder("We are lost -");
  
        astr = new Integer(515);
  
        // Here it appends string representation of Integer
        // argument to this StringBuilder
        sbf.append(astr);
        System.out.println("Result after appending = "+sbf);
    }
}
    输出： 
    We are geeks and its really 
Result after appending = We are geeks and its 827
We are lost -
Result after appending = We are lost -515
  8. StringBuilder append( Long val ) ：此方法只是将 long 参数的字符串表示形式附加到此 StringBuilder 序列。

    句法 ： 

    public StringBuilder append(Long val)

    参数：该方法接受一个参数val ，它是 long 值。

    返回值：该方法执行追加操作后返回一个字符串对象。
    例子 ： 

    Input :
StringBuilder  = I love my Country
Long a = 591995

Output: I love my Country 591995

    下面的程序说明了Java.lang.StringBuilder.append() 方法。 

    // Java program to illustrate the
// java.lang.StringBuilder.append()
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        System.out.println("We are geeks and its really ");
        StringBuilder sbf = new 
                    StringBuilder("We are geeks and its ");
  
        Long astr = new Long(827);
  
        /* Here it appends string representation of 
           Long argument to this StringBuilder*/
        sbf.append(astr);
        System.out.println("Result after appending = "+sbf);
  
        System.out.println("We are lost -");
        sbf = new StringBuilder("We are lost -");
  
        astr = new Long(515);
  
        /* Here it appends string representation of Long 
           argument to this StringBuilder*/
        sbf.append(astr);
        System.out.println("Result after appending = "+sbf);
    }
}
    输出： 
    We are geeks and its really 
Result after appending = We are geeks and its 827
We are lost -
Result after appending = We are lost -515
  9. StringBuilder append( CharSequence a )：该方法用于将指定的 CharSequence 追加到该序列中。

    句法 ： 

    public StringBuilder append(CharSequence a)

    参数：该方法接受单个参数a ，它是 CharSequence 值。

    返回值：该方法执行追加操作后返回一个字符串对象。

    例子 ： 

    Input :
StringBuilder  = "I love my Country" 
CharSequence a = " India"

Output : I love my Country India

    下面的程序说明了Java.lang.StringBuilder.append() 方法。 

    // Java program to illustrate the
// java.lang.StringBuilder.append()
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        StringBuilder sbf = new StringBuilder("Geeksfor");
        System.out.println("String Builder = " + sbf);
  
        CharSequence chSeq = "geeks";
  
        // Appends the CharSequence
        sbf.append(chSeq);
  
        // Print the String Builder after appending
        System.out.println("After append = " + sbf);
    }
}
    输出： 
    String Builder = Geeksfor
After append = Geeksforgeeks
  10. StringBuilder append( CharSequence chseq, int start, int end ) ：此方法用于将指定 CharSequence 的子序列附加到此 StringBuilder。

    句法 ： 

    StringBuilder append(CharSequence chseq, int start, int end)

    参数：该方法接受三个参数：

    • chseq (CharSequence)：这是指 CharSequence 值。
    • start (Integer)：这是指要附加的子序列的起始索引。
    • end (Integer)：这是指要附加的子序列的结束索引。

    返回值：该方法在执行追加操作后返回字符串。

    例子 ： 

    Input :
StringBuilder = Geeksforgeeks
CharSequence chseq = abcd1234
int start = 2
int end = 7

Output :Geeksforgeekscd123

    下面的程序说明了Java.lang.StringBuilder.append() 方法： 

    // Java program to illustrate the
// java.lang.StringBuilder.append()
  
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        StringBuilder sbf = new 
              StringBuilder("We are the ");
        System.out.println("String builder= "
                                      + sbf);
  
        CharSequence chSeq = "wegeekss";
  
        /* It appends the CharSequence with  
           start index 2 and end index 4 */
        sbf.append(chSeq, 2, 7);
  
        System.out.println("After append string"+
                             " buffer = " + sbf);
    }
}
    输出： 
    String builder= We are the 
After append string buffer = We are the geeks
  11. StringBuilder append( Object obj ) ：此方法用于将 Object 参数的字符串表示形式附加到 StringBuilder。

    句法 ： 

    StringBuilder append(Object obj)

    参数：该方法接受单个参数obj ，该参数引用需要附加的对象。

    返回值：该方法在执行追加操作后返回字符串。

    下面的程序说明了Java.lang.StringBuilder.append() 方法。 

    // Java program to illustrate the
// java.lang.StringBuilder.append()
  
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        StringBuilder sbf = new StringBuilder("Geeksfor");
        System.out.println("String Builder = " + sbf);
  
        Object objectvalue = "geeks";
  
        // Here it appends the Object value
        sbf.append(objectvalue);
  
        System.out.println("After appending result is = "+sbf);
    }
}
    输出： 
    String Builder = Geeksfor
After appending result is = Geeksforgeeks
  12. StringBuilder append( String istr ) ：该方法用于将指定的字符串追加到此 StringBuilder 中。
    句法 ： 
    StringBuilder append(String istr)

    参数：该方法接受一个字符串类型的参数istr ，它引用要附加的值。

    返回值：该方法返回一个指定的字符串到这个字符序列。
    下面的程序说明了Java.lang.StringBuilder.append() 方法。 

    // Java program to illustrate the
// java.lang.StringBuilder.append()
  
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        StringBuilder sbf = new StringBuilder("Geeksfor");
        System.out.println("String Builder = " + sbf);
  
        String strvalue = "geeks";
  
        // Here it appends the Object value
        sbf.append(strvalue);
  
        System.out.println("After appending result is = "+sbf);
    }
}
    输出： 
    String Builder = Geeksfor
After appending result is = Geeksforgeeks
  13. StringBuilder append( StringBuilder sbf ) ：该方法用于将指定的 StringBuilder 追加到此序列或 StringBuilder 中。

    句法： 

    public StringBuilder append(StringBuilder sbf)

    参数：该方法接受单个参数sbf是指要附加的StringBuilder。

    返回值：该方法将 StringBuilder 返回到此序列。
    下面的程序说明了Java.lang.StringBuilder.append() 方法。 

    // Java program to illustrate the
// java.lang.StringBuilder.append()
  
import java.lang.*;
  
public class Geeks {
  
    public static void main(String[] args)
    {
  
        StringBuilder sbf1 = new StringBuilder("Geeks");
        System.out.println("String Builder 1 = " + sbf1);
  
        StringBuilder sbf2 = new StringBuilder("forgeeks ");
        System.out.println("String Builder 2 = " + sbf2);
  
        // Here it appends String Builder2 to String Builder1
        sbf1.append(sbf2);
  
        System.out.println("After appending the result is = "+sbf1);
    }
}
    输出： 
    String Builder 1 = Geeks
String Builder 2 = forgeeks 
After appending the result is = Geeksforgeeks