java join字符串连接用法

1,你可以用"+"来连接字符.
2.你可以用stringBuffer的append方法,直接在后面加字符.
你可以用上面两种方法来写出符合你要求的Join方法.

import java.util.HashMap;
import java.util.regex.Pattern;

public class StringHelper {
  
  public static String join(String[] array){
    return join(array, "");
  }
  
  public static String join(String[] array, String delimiter){
  
    int delimiterLength = delimiter.length();

  
    if (array.length == 0) return "";

    
    if (array.length == 1){
      if (array[0] == null) return "";
      return array[0];
    }

  
    // of the resulting string.
    int length = 0;
    for (int i=0; inull.
   * @return        Joined string.
   */
  public static String join(final StringBuffer buff, final Object array[],
     final String delim)
  {
     boolean haveDelim = (delim != null);

     for (int i = 0; i < array.length; i++)
     {
        buff.append(array[i]);

        // if this is the last element then don't append delim
        if (haveDelim && (i + 1) < array.length)
        {
           buff.append(delim);
        }
     }

     return buff.toString();
  }

  /**
   * Join an array of strings into one delimited string.
   *
   * @param array   Array of objects to join as strings.
   * @param delim   Delimiter to join strings with or null.
   * @return        Joined string.
   */
  public static String join(final Object array[], final String delim)
  {
     return join(new StringBuffer(), array, delim);
  }

  /**
   * Convert and join an array of objects into one string.
   *
   * @param array   Array of objects to join as strings.
   * @return        Converted and joined objects.
   */
  public static String join(final Object array[])
  {
     return join(array, null);
  }

  /**
   * Convert and join an array of bytes into one string.
   *
   * @param array   Array of objects to join as strings.
   * @return        Converted and joined objects.
   */
  public static String join(final byte array[])
  {
     Byte bytes[] = new Byte[array.length];
     for (int i = 0; i < bytes.length; i++)
     {
        bytes[i] = new Byte(array[i]);
     }

     return join(bytes, null);
  }

  /**
   * Return a string composed of the given array.
   *
   * @param buff       Buffer used to construct string value (not reset).
   * @param array      Array of objects.
   * @param prefix     String prefix.
   * @param separator  Element sepearator.
   * @param suffix     String suffix.
   * @return           String in the format of:
   *                   prefix + n ( + separator + n+i)* + suffix.
   */
  public static String join(final StringBuffer buff, final Object[] array,
     final String prefix, final String separator,
     final String suffix)
  {
     buff.append(prefix);
     join(buff, array, separator);
     buff.append(suffix);

     return buff.toString();
  }

  /**
   * Return a string composed of the given array.
   *
   * @param array      Array of objects.
   * @param prefix     String prefix.
   * @param separator  Element sepearator.
   * @param suffix     String suffix.
   * @return           String in the format of:
   *                   prefix + n ( + separator + n+i)* + suffix.
   */
  public static String join(final Object[] array, final String prefix,
     final String separator, final String suffix)
  {
     return join(new StringBuffer(), array, prefix, separator, suffix);
  }


}

补充：Jsp教程,Java基础 

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