URI | Java In A Nutshell, 5th Edition

URI

java.net

Java 1.4

serializable comparable

The URI class is an immutable representation of a Uniform Resource Identifier or URI. A URI is a generalization of the URLs or Uniform Resource Locators used on the world wide web. The URI supports parsing and textual manipulation of URI strings, but does not have any direct networking capabilities the way that the URL class does. The advantages of the URI class over the URL class are that it provides more general facilities for parsing and manipulating URLs than the URL class, that it can can represent relative URIs which do not include a scheme (or protocol), and that it can manipulate URIs that include unsupported or even unknown schemes.

Obtain a URI with one of the constructors, which allow a URI to be parsed from a single string, or allow the specification of the individual components of a URI. These constructors can throw URISyntaxException , which is a checked exception. When using hard-coded URIs (rather than URIs based on user input) you may prefer to use the static create( ) method which does not throw any checked exceptions.

Once you have created a URI , object you can use the various get methods to query the various portions of the URI. The getraw( ) methods are like the get( ) methods except that they do not decode hexadecimal escape sequences of the form %xx that appear in the URI. normalize( ) returns a new URI object that has "." and unnecessary ".." sequences removed from its path component. resolve( ) interprets its URI (or string) argument relative to this URI and returns the result. relativize( ) performs the reverse operation. It returns a new URI which represents the same resource as the specified URI argument, but which is relative to this URI . Finally, the toURL( ) method converts an absolute URI object to the equivalent URL . Since the URI class provides superior textual manipulation capabilities for URLs, it can be useful to use the URI class to resolve relative URLs (for example) and then convert those URI objects to URL objects when they are ready for networking.

Figure 12-25. java.net.URI

 public final class  URI  implements Comparable<URI>, Serializable {  // Public Constructors  public  URI  (String  str  ) throws URISyntaxException;        public  URI  (String  scheme  , String  ssp  , String  fragment  )       throws URISyntaxException;        public  URI  (String  scheme  , String  host  , String  path  , String  fragment  )       throws URISyntaxException;        public  URI  (String  scheme  , String  authority  , String  path  , String  query  ,       String  fragment  ) throws URISyntaxException;        public  URI  (String  scheme  , String  userInfo  , String  host  , int  port  ,       String  path  , String  query  , String  fragment  )  throws URISyntaxException;  // Public Class Methods  public static URI  create  (String  str  );  // Public Instance Methods  public String  getAuthority  ( );        public String  getFragment  ( );        public String  getHost  ( );        public String  getPath  ( );        public int  getPort  ( );        public String  getQuery  ( );        public String  getRawAuthority  ( );        public String  getRawFragment  ( );        public String  getRawPath  ( );        public String  getRawQuery  ( );        public String  getRawSchemeSpecificPart  ( );        public String  getRawUserInfo  ( );        public String  getScheme  ( );        public String  getSchemeSpecificPart  ( );        public String  getUserInfo  ( );        public boolean  isAbsolute  ( );        public boolean  isOpaque  ( );        public URI  normalize  ( );        public URI  parseServerAuthority  ( ) throws URISyntaxException;        public URI  relativize  (URI  uri  );        public URI  resolve  (URI  uri  );        public URI  resolve  (String  str  );        public String  toASCIIString  ( );        public URL  toURL  ( ) throws MalformedURLException;  // Methods Implementing Comparable   5.0  public int  compareTo  (URI  that  );  // Public Methods Overriding Object  public boolean  equals  (Object  ob  );        public int  hashCode  ( );        public String  toString  ( );   }

Passed To

java.io.File.File( ) , CookieHandler.{get( ) , put( )} , ProxySelector.{connectFailed( ) , select( )} , ResponseCache.{get( ) , put( )}

Returned By

java.io.File.toURI( ) , URL.toURI( )