customdateeditor.java

一个关于Spring框架的示例应用程序,简单使用,可以参考.

/*
 * Copyright 2002-2004 the original author or authors.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */ 

package org.springframework.beans.propertyeditors;

import java.beans.PropertyEditorSupport;
import java.text.DateFormat;
import java.text.ParseException;
import java.util.Date;

import org.springframework.util.StringUtils;

/**
 * PropertyEditor for java.util.Date, supporting a custom DateFormat.
 *
 * <p>This is not meant to be used as system PropertyEditor but rather as
 * locale-specific date editor within custom controller code, to parse
 * user-entered date strings into Date properties of beans, and render
 * them in the UI form.
 *
 * <p>In web MVC code, this editor will typically be registered with
 * <code>binder.registerCustomEditor</code> calls in an implementation
 * of BaseCommandController's <code>initBinder</code> method.
 *
 * @author Juergen Hoeller
 * @since 28.04.2003
 * @see org.springframework.validation.DataBinder#registerCustomEditor
 * @see org.springframework.web.servlet.mvc.BaseCommandController#initBinder
 * @see org.springframework.web.bind.BindInitializer#initBinder
 */
public class CustomDateEditor extends PropertyEditorSupport {

	private final DateFormat dateFormat;

	private final boolean allowEmpty;

	/**
	 * Create a new CustomDateEditor instance, using the given DateFormat
	 * for parsing and rendering.
	 * <p>The "allowEmpty" parameter states if an empty String should
	 * be allowed for parsing, i.e. get interpreted as null value.
	 * Otherwise, an IllegalArgumentException gets thrown in that case.
	 * @param dateFormat DateFormat to use for parsing and rendering
	 * @param allowEmpty if empty strings should be allowed
	 */
	public CustomDateEditor(DateFormat dateFormat, boolean allowEmpty) {
		this.dateFormat = dateFormat;
		this.allowEmpty = allowEmpty;
	}

	/**
	 * Parse the Date from the given text, using the specified DateFormat.
	 */
	public void setAsText(String text) throws IllegalArgumentException {
		if (this.allowEmpty && !StringUtils.hasText(text)) {
			// treat empty String as null value
			setValue(null);
		}
		else {
			try {
				setValue(this.dateFormat.parse(text));
			}
			catch (ParseException ex) {
				throw new IllegalArgumentException("Could not parse date: " + ex.getMessage());
			}
		}
	}

	/**
	 * Format the Date as String, using the specified DateFormat.
	 */
	public String getAsText() {
		return (getValue() == null ? "" : this.dateFormat.format((Date) getValue()));
	}

}