Java Array轉String用法及代碼示例

以下是在 Java 中將數組轉換為字符串的各種方法：

1. Java Arrays.toString()用法及代碼示例：Arrays.toString() 方法用於返回指定數組內容的字符串表示形式。字符串表示由數組元素的列表組成，括在方括號 (“[]”) 中。相鄰元素由字符“, ”(逗號後跟一個空格)分隔。如果數組為空，則返回 “null”。

   
   // Java program to demonstrate
   // working of Arrays.toString()
     
   import java.io.*;
   import java.util.*;
     
   class GFG {
       public static void main(String[] args)
       {
     
           // Let us create different types of arrays and
           // print their contents using Arrays.toString()
           boolean[] boolArr
               = new boolean[] { true, true, false, true };
           char[] charArr
               = new char[] { 'g', 'e', 'e', 'k', 's' };
           double[] dblArr
               = new double[] { 1, 2, 3, 4 };
           int[] intArr
               = new int[] { 1, 2, 3, 4 };
           Object[] objArr
               = new Object[] { 1, 2, 3, 4 };
     
           System.out.println(
               "Boolean Array:"
               + Arrays.toString(boolArr));
           System.out.println(
               "Character Array:"
               + Arrays.toString(charArr));
           System.out.println(
               "Double Array:"
               + Arrays.toString(dblArr));
           System.out.println(
               "Integer Array:"
               + Arrays.toString(intArr));
           System.out.println(
               "Object Array:"
               + Arrays.toString(objArr));
       }
   }

   輸出：

   Boolean Array:[true, true, false, true]
   Character Array:[g, e, e, k, s]
   Double Array:[1.0, 2.0, 3.0, 4.0]
   Integer Array:[1, 2, 3, 4]
   Object Array:[1, 2, 3, 4]
   

2. Java StringBuilder append()用法及代碼示例：java.lang.StringBuilder.append(char[]) 是內置方法，它將 char 數組參數的字符串表示附加到此 StringBuilder 序列。

   
   // Java program to illustrate the
   // StringBuilder.append(char[]) method
     
   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);
       }
   }

   輸出：

   We are geeks 
   Result after appending = We are geeks GEEkS
   We are -
   Result after appending = We are -abcd