requestutils.java

一个关于Spring框架的示例应用程序,简单使用,可以参考.

	}


	/**
	 * Get a Boolean parameter, or null if not present.
	 * Throws an exception if it the parameter value isn't a boolean.
	 * <p>Accepts "true", "on", "yes" (any case) and "1" as values for true;
	 * treats every other non-empty value as false (i.e. parses leniently).
	 * @param request current HTTP request
	 * @param name the name of the parameter
	 * @return the Boolean value, or null if not present
	 * @throws ServletRequestBindingException: subclass of ServletException,
	 * so it doesn't need to be caught
	 */
	public static Boolean getBooleanParameter(HttpServletRequest request, String name)
			throws ServletRequestBindingException {
		if (request.getParameter(name) == null) {
			return null;
		}
		return (getRequiredBooleanParameter(request, name) ? Boolean.TRUE : Boolean.FALSE);
	}

	/**
	 * Get a boolean parameter, with a fallback value. Never throws an exception.
	 * Can pass a distinguished value as default to enable checks of whether it was supplied.
	 * <p>Accepts "true", "on", "yes" (any case) and "1" as values for true;
	 * treats every other non-empty value as false (i.e. parses leniently).
	 * @param request current HTTP request
	 * @param name the name of the parameter
	 * @param defaultVal the default value to use as fallback
	 */
	public static boolean getBooleanParameter(HttpServletRequest request, String name, boolean defaultVal) {
		try {
			return getRequiredBooleanParameter(request, name);
		}
		catch (ServletRequestBindingException ex) {
			return defaultVal;
		}
	}

	/**
	 * Get an array of boolean parameters, return an empty array if not found.
	 * <p>Accepts "true", "on", "yes" (any case) and "1" as values for true;
	 * treats every other non-empty value as false (i.e. parses leniently).
	 * @param request current HTTP request
	 * @param name the name of the parameter with multiple possible values
	 */
	public static boolean[] getBooleanParameters(HttpServletRequest request, String name) {
		try {
			return getRequiredBooleanParameters(request, name);
		}
		catch (ServletRequestBindingException ex) {
			return new boolean[0];
		}
	}

	/**
	 * Get an array of boolean parameters, throwing an exception if it isn't found
	 * or isn't a boolean.
	 * <p>Accepts "true", "on", "yes" (any case) and "1" as values for true;
	 * treats every other non-empty value as false (i.e. parses leniently).
	 * @param request current HTTP request
	 * @param name the name of the parameter
	 * @throws ServletRequestBindingException: subclass of ServletException,
	 * so it doesn't need to be caught
	 */
	public static boolean getRequiredBooleanParameter(HttpServletRequest request, String name)
			throws ServletRequestBindingException {
		return BOOLEAN_PARSER.parseBoolean(name, request.getParameter(name));
	}

	/**
	 * Get an array of boolean parameters, throwing an exception if not found
	 * or one isn't a boolean.
	 * <p>Accepts "true", "on", "yes" (any case) and "1" as values for true;
	 * treats every other non-empty value as false (i.e. parses leniently).
	 * @param request current HTTP request
	 * @param name the name of the parameter
	 * @throws ServletRequestBindingException: subclass of ServletException,
	 * so it doesn't need to be caught
	 */
	public static boolean[] getRequiredBooleanParameters(HttpServletRequest request, String name)
			throws ServletRequestBindingException {
		return BOOLEAN_PARSER.parseBooleans(name, request.getParameterValues(name));
	}


	/**
	 * Get a String parameter, or null if not present.
	 * Throws an exception if it the parameter value is empty.
	 * @param request current HTTP request
	 * @param name the name of the parameter
	 * @return the String value, or null if not present
	 * @throws ServletRequestBindingException: subclass of ServletException,
	 * so it doesn't need to be caught
	 */
	public static String getStringParameter(HttpServletRequest request, String name)
			throws ServletRequestBindingException {
		if (request.getParameter(name) == null) {
			return null;
		}
		return getRequiredStringParameter(request, name);
	}

	/**
	 * Get a string parameter, with a fallback value. Never throws an exception.
	 * Can pass a distinguished value to default to enable checks of whether it was supplied.
	 * @param request current HTTP request
	 * @param name the name of the parameter
	 * @param defaultVal the default value to use as fallback
	 */
	public static String getStringParameter(HttpServletRequest request, String name, String defaultVal) {
		try {
			return getRequiredStringParameter(request, name);
		}
		catch (ServletRequestBindingException ex) {
			return defaultVal;
		}
	}

	/**
	 * Get an array of String parameters, return an empty array if not found.
	 * @param request current HTTP request
	 * @param name the name of the parameter with multiple possible values
	 */
	public static String[] getStringParameters(HttpServletRequest request, String name) {
		try {
			return getRequiredStringParameters(request, name);
		}
		catch (ServletRequestBindingException ex) {
			return new String[0];
		}
	}

	/**
	 * Get a string parameter, throwing an exception if it isn't found or is empty.
	 * @param request current HTTP request
	 * @param name the name of the parameter
	 * @throws ServletRequestBindingException: subclass of ServletException,
	 * so it doesn't need to be caught
	 */
	public static String getRequiredStringParameter(HttpServletRequest request, String name)
			throws ServletRequestBindingException {
		return STRING_PARSER.validateRequiredString(name, request.getParameter(name));
	}

	/**
	 * Get an array of string parameters, throwing an exception if not found or one is empty.
	 * @param request current HTTP request
	 * @param name the name of the parameter
	 * @throws ServletRequestBindingException: subclass of ServletException,
	 * so it doesn't need to be caught
	 */
	public static String[] getRequiredStringParameters(HttpServletRequest request, String name)
			throws ServletRequestBindingException {
		return STRING_PARSER.validateRequiredStrings(name, request.getParameterValues(name));
	}


	private abstract static class ParameterParser {

		protected final Object parse(String name, String parameter) throws ServletRequestBindingException {
			validateRequiredParameter(name, parameter);
			try {
				return doParse(parameter);
			}
			catch (NumberFormatException ex) {
				throw new ServletRequestBindingException("Required " + getType() + " parameter '" + name
						+ "' with value of '" + parameter + "' is not a valid number");
			}
		}

		protected final void validateRequiredParameter(String name, Object parameter)
				throws ServletRequestBindingException {
			if (parameter == null) {
				throw new ServletRequestBindingException("Required " + getType() + " parameter '" + name
						+ "' is not present");
			}
			if ("".equals(parameter)) {
				throw new ServletRequestBindingException("Required " + getType() + " parameter '" + name
						+ "' contains no value");
			}
		}

		protected abstract String getType();

		protected abstract Object doParse(String parameter) throws NumberFormatException;
	}


	private static class IntParser extends ParameterParser {

		protected String getType() {
			return "int";
		}

		protected Object doParse(String s) throws NumberFormatException {
			return Integer.valueOf(s);
		}

		public int parseInt(String name, String parameter) throws ServletRequestBindingException {
			return ((Number) parse(name, parameter)).intValue();
		}

		public int[] parseInts(String name, String[] values) throws ServletRequestBindingException {
			validateRequiredParameter(name, values);
			int[] parameters = new int[values.length];
			for (int i = 0; i < values.length; i++) {
				parameters[i] = parseInt(name, values[i]);
			}
			return parameters;
		}
	}


	private static class LongParser extends ParameterParser {

		protected String getType() {
			return "long";
		}

		protected Object doParse(String parameter) throws NumberFormatException {
			return Long.valueOf(parameter);
		}

		public long parseLong(String name, String parameter) throws ServletRequestBindingException {
			return ((Number) parse(name, parameter)).longValue();
		}

		public long[] parseLongs(String name, String[] values) throws ServletRequestBindingException {
			validateRequiredParameter(name, values);
			long[] parameters = new long[values.length];
			for (int i = 0; i < values.length; i++) {
				parameters[i] = parseLong(name, values[i]);
			}
			return parameters;
		}
	}


	private static class FloatParser extends ParameterParser {

		protected String getType() {
			return "float";
		}

		protected Object doParse(String parameter) throws NumberFormatException {
			return Float.valueOf(parameter);
		}

		public float parseFloat(String name, String parameter) throws ServletRequestBindingException {
			return ((Number) parse(name, parameter)).floatValue();
		}

		public float[] parseFloats(String name, String[] values) throws ServletRequestBindingException {
			validateRequiredParameter(name, values);
			float[] parameters = new float[values.length];
			for (int i = 0; i < values.length; i++) {
				parameters[i] = parseFloat(name, values[i]);
			}
			return parameters;
		}
	}


	private static class DoubleParser extends ParameterParser {

		protected String getType() {
			return "double";
		}

		protected Object doParse(String parameter) throws NumberFormatException {
			return Double.valueOf(parameter);
		}

		public double parseDouble(String name, String parameter) throws ServletRequestBindingException {
			return ((Number) parse(name, parameter)).doubleValue();
		}

		public double[] parseDoubles(String name, String[] values) throws ServletRequestBindingException {
			validateRequiredParameter(name, values);
			double[] parameters = new double[values.length];
			for (int i = 0; i < values.length; i++) {
				parameters[i] = parseDouble(name, values[i]);
			}
			return parameters;
		}
	}


	private static class BooleanParser extends ParameterParser {

		protected String getType() {
			return "boolean";
		}

		protected Object doParse(String parameter) throws NumberFormatException {
			return (parameter.equalsIgnoreCase("true") || parameter.equalsIgnoreCase("on") ||
					parameter.equalsIgnoreCase("yes") || parameter.equals("1") ? Boolean.TRUE : Boolean.FALSE);
		}

		public boolean parseBoolean(String name, String parameter) throws ServletRequestBindingException {
			return ((Boolean) parse(name, parameter)).booleanValue();
		}

		public boolean[] parseBooleans(String name, String[] values) throws ServletRequestBindingException {
			validateRequiredParameter(name, values);
			boolean[] parameters = new boolean[values.length];
			for (int i = 0; i < values.length; i++) {
				parameters[i] = parseBoolean(name, values[i]);
			}
			return parameters;
		}
	}


	private static class StringParser extends ParameterParser {

		protected String getType() {
			return "string";
		}

		protected Object doParse(String parameter) throws NumberFormatException {
			return parameter;
		}

		public String validateRequiredString(String name, String value)
				throws ServletRequestBindingException {
			validateRequiredParameter(name, value);
			return value;
		}

		public String[] validateRequiredStrings(String name, String[] values)
				throws ServletRequestBindingException {
			validateRequiredParameter(name, values);
			for (int i = 0; i < values.length; i++) {
				validateRequiredParameter(name, values[i]);
			}
			return values;
		}
	}

}