org.apache.commons.lang
Class StringEscapeUtils

java.lang.Object
  org.apache.commons.lang.StringEscapeUtils

public class StringEscapeUtils

extends Object

Escapes and unescapes Strings for Java, Java Script, HTML, XML, and SQL.

Since:

2.0

Version:

$Id: StringEscapeUtils.java,v 1.25 2003/08/18 02:22:23 bayard Exp $

Author:

Apache Jakarta Turbine, GenerationJavaCore library, Purple Technology, Henri Yandell, Alexander Day Chaffee, Antony Riley, Helge Tesgaard, Sean Brown, Gary Gregory, Phil Steitz, Pete Gieser

Constructor Summary

StringEscapeUtils()
StringEscapeUtils instances should NOT be constructed in standard programming.

Method Summary

static String	escapeHtml(String str) Escapes the characters in a String using HTML entities.
static String	escapeJava(String str) Escapes the characters in a String using Java String rules.
static void	escapeJava(Writer out, String str) Escapes the characters in a String using Java String rules to a Writer.
static String	escapeJavaScript(String str) Escapes the characters in a String using JavaScript String rules.
static void	escapeJavaScript(Writer out, String str) Escapes the characters in a String using JavaScript String rules to a Writer.
static String	escapeSql(String str) Escapes the characters in a String to be suitable to pass to an SQL query.
static String	escapeXml(String str) Escapes the characters in a String using XML entities.
static String	unescapeHtml(String str) Unescapes a string containing entity escapes to a string containing the actual Unicode characters corresponding to the escapes.
static String	unescapeJava(String str) Unescapes any Java literals found in the String.
static void	unescapeJava(Writer out, String str) Unescapes any Java literals found in the String to a Writer.
static String	unescapeJavaScript(String str) Unescapes any JavaScript literals found in the String.
static void	unescapeJavaScript(Writer out, String str) Unescapes any JavaScript literals found in the String to a Writer.
static String	unescapeXml(String str) Unescapes a string containing XML entity escapes to a string containing the actual Unicode characters corresponding to the escapes.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

StringEscapeUtils

public StringEscapeUtils()

StringEscapeUtils instances should NOT be constructed in standard programming.

Instead, the class should be used as:

StringEscapeUtils.escapeJava("foo");

This constructor is public to permit tools that require a JavaBean instance to operate.

Method Detail

escapeJava

public static String escapeJava(String str)

Escapes the characters in a String using Java String rules.

Deals correctly with quotes and control-chars (tab, backslash, cr, ff, etc.)

So a tab becomes the characters '\\' and 't'.

The only difference between Java strings and JavaScript strings is that in JavaScript, a single quote must be escaped.

Example:

 input string: He didn't say, "Stop!"
 output string: He didn't say, \"Stop!\"
 

Parameters:

str - String to escape values in, may be null

Returns:

String with escaped values, null if null string input

escapeJava

public static void escapeJava(Writer out,
                              String str)
                       throws IOException

Escapes the characters in a String using Java String rules to a Writer.

A null string input has no effect.

Parameters:

out - Writer to write escaped string into

str - String to escape values in, may be null

Throws:

IllegalArgumentException - if the Writer is null

IOException - if error occurs on undelying Writer

See Also:

escapeJava(java.lang.String)

escapeJavaScript

public static String escapeJavaScript(String str)

Escapes the characters in a String using JavaScript String rules.

Escapes any values it finds into their JavaScript String form. Deals correctly with quotes and control-chars (tab, backslash, cr, ff, etc.)

So a tab becomes the characters '\\' and 't'.

The only difference between Java strings and JavaScript strings is that in JavaScript, a single quote must be escaped.

Example:

 input string: He didn't say, "Stop!"
 output string: He didn\'t say, \"Stop!\"
 

Parameters:

str - String to escape values in, may be null

Returns:

String with escaped values, null if null string input

escapeJavaScript

public static void escapeJavaScript(Writer out,
                                    String str)
                             throws IOException

Escapes the characters in a String using JavaScript String rules to a Writer.

A null string input has no effect.

Parameters:

out - Writer to write escaped string into

str - String to escape values in, may be null

Throws:

IllegalArgumentException - if the Writer is null

IOException - if error occurs on undelying Writer

See Also:

escapeJavaScript(java.lang.String)

unescapeJava

public static String unescapeJava(String str)

Unescapes any Java literals found in the String. For example, it will turn a sequence of '\' and 'n' into a newline character, unless the '\' is preceded by another '\'.

Parameters:

str - the String to unescape, may be null

Returns:

a new unescaped String, null if null string input

unescapeJava

public static void unescapeJava(Writer out,
                                String str)
                         throws IOException

Unescapes any Java literals found in the String to a Writer.

For example, it will turn a sequence of '\' and 'n' into a newline character, unless the '\' is preceded by another '\'.

A null string input has no effect.

Parameters:

out - the Writer used to output unescaped characters

str - the String to unescape, may be null

Throws:

IllegalArgumentException - if the Writer is null

IOException - if error occurs on undelying Writer

unescapeJavaScript

public static String unescapeJavaScript(String str)

Unescapes any JavaScript literals found in the String.

For example, it will turn a sequence of '\' and 'n' into a newline character, unless the '\' is preceded by another '\'.

Parameters:

str - the String to unescape, may be null

Returns:

A new unescaped String, null if null string input

See Also:

unescapeJava(String)

unescapeJavaScript

public static void unescapeJavaScript(Writer out,
                                      String str)
                               throws IOException

Unescapes any JavaScript literals found in the String to a Writer.

For example, it will turn a sequence of '\' and 'n' into a newline character, unless the '\' is preceded by another '\'.

A null string input has no effect.

Parameters:

out - the Writer used to output unescaped characters

str - the String to unescape, may be null

Throws:

IllegalArgumentException - if the Writer is null

IOException - if error occurs on undelying Writer

See Also:

unescapeJava(Writer,String)

escapeHtml

public static String escapeHtml(String str)

Escapes the characters in a String using HTML entities.

For example: "bread" & "butter" => "bread" & "butter".

Supports all known HTML 4.0 entities, including funky accents.

Parameters:

str - the String to escape, may be null

Returns:

a new escaped String, null if null string input

See Also:

unescapeHtml(String),
ISO Entities,
HTML 3.2 Character Entities for ISO Latin-1,
HTML 4.0 Character entity references,
HTML 4.01 Character References,
HTML 4.01 Code positions

unescapeHtml

public static String unescapeHtml(String str)

Unescapes a string containing entity escapes to a string containing the actual Unicode characters corresponding to the escapes. Supports HTML 4.0 entities.

For example, the string "&lt;Fran&ccedil;ais&gt;" will become "<Français>"

If an entity is unrecognized, it is left alone, and inserted verbatim into the result string. e.g. "&gt;&zzzz;x" will become ">&zzzz;x".

Parameters:

str - the String to unescape, may be null

Returns:

a new unescaped String, null if null string input

See Also:

escapeHtml(String)

escapeXml

public static String escapeXml(String str)

Escapes the characters in a String using XML entities.

For example: "bread" & "butter" => &quot;bread&quot; &amp; &quot;butter&quot;.

Supports only the four basic XML entities (gt, lt, quot, amp). Does not support DTDs or external entities.

Parameters:

str - the String to escape, may be null

Returns:

a new escaped String, null if null string input

See Also:

unescapeXml(java.lang.String)

unescapeXml

public static String unescapeXml(String str)

Unescapes a string containing XML entity escapes to a string containing the actual Unicode characters corresponding to the escapes.

Supports only the four basic XML entities (gt, lt, quot, amp). Does not support DTDs or external entities.

Parameters:

str - the String to unescape, may be null

Returns:

a new unescaped String, null if null string input

See Also:

escapeXml(String)

escapeSql

public static String escapeSql(String str)

Escapes the characters in a String to be suitable to pass to an SQL query.

For example,

statement.executeQuery("SELECT * FROM MOVIES WHERE TITLE='" + 
   StringEscapeUtils.escapeSql("McHale's Navy") + 
   "'");

At present, this method only turns single-quotes into doubled single-quotes ("McHale's Navy" => "McHale''s Navy"). It does not handle the cases of percent (%) or underscore (_) for use in LIKE clauses.

see http://www.jguru.com/faq/view.jsp?EID=8881

Parameters:

str - the string to escape, may be null

Returns:

a new String, escaped for SQL, null if null string input