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  • char charAt(int index)

    returns the character at the specified location.

  • int compareTo(String other)

    returns a negative value if the string comes before other in dictionary order, a positive value if the string comes after other in dictionary order, or 0 if the strings are equal.

  • boolean endsWith(String suffix)

    returns true if the string ends with suffix.

  • boolean equals(Object other)

    returns true if the string equals other.

  • boolean equalsIgnoreCase(String other)

    returns true if the string equals other, except for upper/lowercase distinction.

  • int indexOf(String str)

  • int indexOf(String str, int fromIndex)

    return the start of the first substring equal to str, starting at index 0 or at fromIndex.

  • int lastIndexOf(String str)

  • int lastIndexOf(String str, int fromIndex)

    return the start of the last substring equal to str, starting at the end of the string or at fromIndex.

  • int length()

    returns the length of the string.

  • String replace(char oldChar, char newChar)

    returns a new string that is obtained by replacing all characters oldChar in the string with newChar.

  • boolean startsWith(String prefix)

    returns true if the string begins with prefix.

  • String substring(int beginIndex)

  • String substring(int beginIndex, int endIndex)

    return a new string consisting of all characters from beginIndex until the end of the string or until endIndex (exclusive).

  • String toLowerCase()

    returns a new string containing all characters in the original string, with uppercase characters converted to lower case.

  • String toUpperCase()

    returns a new string containing all characters in the original string, with lowercase characters converted to upper case.

  • String trim()

    returns a new string by eliminating all leading and trailing spaces in the original string.

字符串与基本数据类型的转换间的转换必须使用JSP中的对象函数
Boolean.getBoolean(String)
Byte.parseByte(String)
Short.parseShort(String)
Integer.parseInt(String)
Long.parseLong(String)
Float.parseDouble(String)
Double.parseDouble(String)
String.valueOF(数据)


Array

  • static void arraycopy(Object from, int fromIndex, Object to, int toIndex, int count)

    Parameters:

    from

    an array of any type (Chapter 5 explains why this is a parameter of type Object)

     

    fromIndex

    the starting index from which to copy elements

     

    to

    an array of the same type as from

     

    toIndex

    the starting index to which to copy elements

     

    count

    the number of elements to copy

    copies elements from the first array to the second array.

    java.util.Arrays 1.2

     

    • static void sort(Xxx[] a)

      Parameters:

      a

      an array of type int, long, short, char, byte, boolean, float or double

      sorts the array, using a tuned QuickSort algorithm.

    • static int binarySearch(Xxx[] a, Xxx v)

      Parameters:

      a

      a sorted array of type int, long, short, char, byte, boolean, float or double

       

      v

      a value of the same type as the elements of a

      uses the BinarySearch algorithm to search for the value v. If it is found, its index is returned. Otherwise, a negative value r is returned; -r - 1 is the spot at which v should be inserted to keep a sorted.

    • static void fill(Xxx[] a, Xxx v)

      Parameters:

      a

      an array of type int, long, short, char, byte, boolean, float or double

       

      v

      a value of the same type as the elements of a

      sets all elements of the array to v.

    • static boolean equals(Xxx[] a, Object other)

      Parameters:

      a

      an array of type int, long, short, char, byte, boolean, float or double

       

      other

      an object

      returns true if other is an array of the same type, if it has the same length, and if the elements in corresponding indexes match.

  • eg: 

     int[] smallPrimes = {2, 3, 5, 7, 11, 13};
      int[] luckyNumbers = {1001, 1002, 1003, 1004, 1005, 1006, 1007};
      System.arraycopy(smallPrimes, 2, luckyNumbers, 3, 3);
      for (int i = 0; i < luckyNumbers.length; i++)
         System.out.println(i + ": " + luckyNumbers[i]);

    posted on 2005-09-05 13:56 my java 阅读(332) 评论(0)  编辑  收藏 所属分类: java

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