java方法大全（Java method Daquan）.doc

java方法大全（Java method Daquan） Java common methods Daquan Character string 1. Get the length of a string Length () 2. Determine whether the prefix or suffix of a string is the same as a known string Prefix startsWith (String s) Suffix endsWith (String s) 3. Compare two strings Equals (String s) 4. Convert the string to the corresponding numeric value Int Integer.parseInt (string) Long Long.parseLong (string) Float type Folat.valueOf (string).FloatValue () Double type Double.valueOf (string).DoubleValue () 4. Convert numeric values to strings ValueOf (numerical) 5, string search IndexOf (Srting s) retrieval from scratch IndexOf (String s, int startpoint) retrieves from startpoint If not retrieved, -1 will be returned 6. Get the substring of a string Substring (int startpoint) starts from startpoint Characters in substring (int start, int end) from start to end 7, replace the string character, remove the string before and after the space Replace (char old, char new) replaces old with new (trim) 8. String analysis StringTokenizer (String s) constructs a parser that uses default delimited characters (spaces, newline, carriage returns, Tab, feed characters) StringTokenizer (String s, String delim) delim is a delimiter defined by itself NextToken () gets the language symbols in a string one by one Boolean hasMoreTokens () returns true as long as the string has a language symbol, otherwise false is returned How many language symbols are there in countTokens? Text box and text area 1, text box TextField () constructs a text box, one character long TextField (int x) constructs a text box, X characters long TextField (String s) constructs a text box and displays s SetText (String s) sets the text to s GetText () gets text SetEchoChar (char c) sets the display character to C SetEditable (Boolean) sets whether the text box can be modified AddActionListener () add monitor RemoveActionListener () remove monitor 2, text area TextArea () constructs the text area TextArea (String s) c