网上图书商城项目学习笔记-036工具类之CommonUtils及日期转换器

1.CommonUtils.java

 package cn.itcast.commons;

 import java.util.Map;
 import java.util.UUID;

 import org.apache.commons.beanutils.BeanUtils;
 import org.apache.commons.beanutils.ConvertUtils;

 /**
  * 小小工具
  * @author qdmmy6
  *
  */
 public class CommonUtils {
     /**
      * 返回一个不重复的字符串
      * @return
      */
     public static String uuid() {
         return UUID.randomUUID().toString().replace("-", "").toUpperCase();
     }

     /**
      * 把map转换成对象
      * @param map
      * @param clazz
      * @return
      *
      * 把Map转换成指定类型
      */
     @SuppressWarnings("rawtypes")
     public static <T> T toBean(Map map, Class<T> clazz) {
         try {
             /*
              * 1. 通过参数clazz创建实例
              * 2. 使用BeanUtils.populate把map的数据封闭到bean中
              */
             T bean = clazz.newInstance();
             ConvertUtils.register(new DateConverter(), java.util.Date.class);
             BeanUtils.populate(bean, map);
             return bean;
         } catch(Exception e) {
             throw new RuntimeException(e);
         }
     }
 }

2.DateConverter.java

 package cn.itcast.commons;

 import java.text.ParseException;
 import java.text.SimpleDateFormat;

 import org.apache.commons.beanutils.Converter;

 /**
  * 把String转换成java.util.Date的类型转换器
  * @author qdmmy6
  *
  */
 public class DateConverter implements Converter {

     @SuppressWarnings("rawtypes")
     @Override
     public Object convert(Class type, Object value) {
         if(value == null) return null;//如果要转换成值为null，那么直接返回null
         if(!(value instanceof String)) {//如果要转换的值不是String，那么就不转换了，直接返回
             return value;
         }
         String val = (String) value;//把值转换成String

         // 使用SimpleDateFormat进行转换
         SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
         try {
             return sdf.parse(val);
         } catch (ParseException e) {
             throw new RuntimeException(e);
         }
     }
 }

3..BeanUtils.java

 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You 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.apache.commons.beanutils;

 import java.lang.reflect.InvocationTargetException;
 import java.util.Map;

 /**
  * <p>Utility methods for populating JavaBeans properties via reflection.</p>
  *
  * <p>The implementations are provided by {@link BeanUtilsBean}.
  * These static utility methods use the default instance.
  * More sophisticated behaviour can be provided by using a <code>BeanUtilsBean</code> instance.</p>
  *
  * @author Craig R. McClanahan
  * @author Ralph Schaer
  * @author Chris Audley
  * @author Rey Francois
  * @author Gregor Rayman
  * @version $Revision: 690380 $ $Date: 2008-08-29 21:04:38 +0100 (Fri, 29 Aug 2008) $
  * @see BeanUtilsBean
  */

 public class BeanUtils {

     // ------------------------------------------------------ Private Variables

     /**
      * The debugging detail level for this component.
      *
      * Note that this static variable will have unexpected side-effects if
      * this class is deployed in a shared classloader within a container.
      * However as it is actually completely ignored by this class due to its
      * deprecated status, it doesn't do any actual harm.
      *
      * @deprecated BeanUtils now uses commons-logging for all log messages.
      *             Use your favorite logging tool to configure logging for
      *             this class.
      */
     private static int debug = 0;

     /**
      * The <code>debug</code> static property is no longer used
      * @return debug property
      * @deprecated BeanUtils now uses commons-logging for all log messages.
      *             Use your favorite logging tool to configure logging for
      *             this class.
      */
     public static int getDebug() {
         return (debug);
     }

     /**
      * The <code>debug</code> static property is no longer used
      * @param newDebug debug property
      * @deprecated BeanUtils now uses commons-logging for all log messages.
      *             Use your favorite logging tool to configure logging for
      *             this class.
      */
     public static void setDebug(int newDebug) {
         debug = newDebug;
     }

     // --------------------------------------------------------- Class Methods

     /**
      * <p>Clone a bean based on the available property getters and setters,
      * even if the bean class itself does not implement Cloneable.</p>
      *
      * <p>For more details see <code>BeanUtilsBean</code>.</p>
      *
      * @param bean Bean to be cloned
      * @return the cloned bean
      *
      * @exception IllegalAccessException if the caller does not have
      *  access to the property accessor method
      * @exception InstantiationException if a new instance of the bean's
      *  class cannot be instantiated
      * @exception InvocationTargetException if the property accessor method
      *  throws an exception
      * @exception NoSuchMethodException if an accessor method for this
      *  property cannot be found
      * @see BeanUtilsBean#cloneBean
      */
     public static Object cloneBean(Object bean)
             throws IllegalAccessException, InstantiationException,
             InvocationTargetException, NoSuchMethodException {

         return BeanUtilsBean.getInstance().cloneBean(bean);

     }

     /**
      * <p>Copy property values from the origin bean to the destination bean
      * for all cases where the property names are the same.</p>
      *
      * <p>For more details see <code>BeanUtilsBean</code>.</p>
      *
      * @param dest Destination bean whose properties are modified
      * @param orig Origin bean whose properties are retrieved
      *
      * @exception IllegalAccessException if the caller does not have
      *  access to the property accessor method
      * @exception IllegalArgumentException if the <code>dest</code> or
      *  <code>orig</code> argument is null or if the <code>dest</code>
      *  property type is different from the source type and the relevant
      *  converter has not been registered.
      * @exception InvocationTargetException if the property accessor method
      *  throws an exception
      * @see BeanUtilsBean#copyProperties
      */
     public static void copyProperties(Object dest, Object orig)
         throws IllegalAccessException, InvocationTargetException {

         BeanUtilsBean.getInstance().copyProperties(dest, orig);
     }

     /**
      * <p>Copy the specified property value to the specified destination bean,
      * performing any type conversion that is required.</p>
      *
      * <p>For more details see <code>BeanUtilsBean</code>.</p>
      *
      * @param bean Bean on which setting is to be performed
      * @param name Property name (can be nested/indexed/mapped/combo)
      * @param value Value to be set
      *
      * @exception IllegalAccessException if the caller does not have
      *  access to the property accessor method
      * @exception InvocationTargetException if the property accessor method
      *  throws an exception
      * @see BeanUtilsBean#copyProperty
      */
     public static void copyProperty(Object bean, String name, Object value)
         throws IllegalAccessException, InvocationTargetException {

         BeanUtilsBean.getInstance().copyProperty(bean, name, value);
     }

     /**
      * <p>Return the entire set of properties for which the specified bean
      * provides a read method.</p>
      *
      * <p>For more details see <code>BeanUtilsBean</code>.</p>
      *
      * @param bean Bean whose properties are to be extracted
      * @return Map of property descriptors
      *
      * @exception IllegalAccessException if the caller does not have
      *  access to the property accessor method
      * @exception InvocationTargetException if the property accessor method
      *  throws an exception
      * @exception NoSuchMethodException if an accessor method for this
      *  property cannot be found
      * @see BeanUtilsBean#describe
      */
     public static Map describe(Object bean)
             throws IllegalAccessException, InvocationTargetException,
             NoSuchMethodException {

         return BeanUtilsBean.getInstance().describe(bean);
     }

     /**
      * <p>Return the value of the specified array property of the specified
      * bean, as a String array.</p>
      *
      * <p>For more details see <code>BeanUtilsBean</code>.</p>
      *
      * @param bean Bean whose property is to be extracted
      * @param name Name of the property to be extracted
      * @return The array property value
      *
      * @exception IllegalAccessException if the caller does not have
      *  access to the property accessor method
      * @exception InvocationTargetException if the property accessor method
      *  throws an exception
      * @exception NoSuchMethodException if an accessor method for this
      *  property cannot be found
      * @see BeanUtilsBean#getArrayProperty
      */
     public static String[] getArrayProperty(Object bean, String name)
             throws IllegalAccessException, InvocationTargetException,
             NoSuchMethodException {

         return BeanUtilsBean.getInstance().getArrayProperty(bean, name);
     }

     /**
      * <p>Return the value of the specified indexed property of the specified
      * bean, as a String.</p>
      *
      * <p>For more details see <code>BeanUtilsBean</code>.</p>
      *
      * @param bean Bean whose property is to be extracted
      * @param name <code>propertyname[index]</code> of the property value
      *  to be extracted
      * @return The indexed property's value, converted to a String
      *
      * @exception IllegalAccessException if the caller does not have
      *  access to the property accessor method
      * @exception InvocationTargetException if the property accessor method
      *  throws an exception
      * @exception NoSuchMethodException if an accessor method for this
      *  property cannot be found
      * @see BeanUtilsBean#getIndexedProperty(Object, String)
      */
     public static String getIndexedProperty(Object bean, String name)
             throws IllegalAccessException, InvocationTargetException,
             NoSuchMethodException {

         return BeanUtilsBean.getInstance().getIndexedProperty(bean, name);

     }

     /**
      * Return the value of the specified indexed property of the specified
      * bean, as a String.  The index is specified as a method parameter and
      * must *not* be included in the property name expression
      *
      * <p>For more details see <code>BeanUtilsBean</code>.</p>
      *
      * @param bean Bean whose property is to be extracted
      * @param name Simple property name of the property value to be extracted
      * @param index Index of the property value to be extracted
      * @return The indexed property's value, converted to a String
      *
      * @exception IllegalAccessException if the caller does not have
      *  access to the property accessor method
      * @exception InvocationTargetException if the property accessor method
      *  throws an exception
      * @exception NoSuchMethodException if an accessor method for this
      *  property cannot be found
      * @see BeanUtilsBean#getIndexedProperty(Object, String, int)
      */
     public static String getIndexedProperty(Object bean,
                                             String name, int index)
             throws IllegalAccessException, InvocationTargetException,
             NoSuchMethodException {

         return BeanUtilsBean.getInstance().getIndexedProperty(bean, name, index);

     }

     /**
      * </p>Return the value of the specified indexed property of the specified
      * bean, as a String.</p>
      *
      * <p>For more details see <code>BeanUtilsBean</code>.</p>
      *
      * @param bean Bean whose property is to be extracted
      * @param name <code>propertyname(index)</code> of the property value
      *  to be extracted
      * @return The mapped property's value, converted to a String
      *
      * @exception IllegalAccessException if the caller does not have
      *  access to the property accessor method
      * @exception InvocationTargetException if the property accessor method
      *  throws an exception
      * @exception NoSuchMethodException if an accessor method for this
      *  property cannot be found
      * @see BeanUtilsBean#getMappedProperty(Object, String)
      */
     public static String getMappedProperty(Object bean, String name)
             throws IllegalAccessException, InvocationTargetException,
             NoSuchMethodException {

         return BeanUtilsBean.getInstance().getMappedProperty(bean, name);

     }

     /**
      * </p>Return the value of the specified mapped property of the specified
      * bean, as a String.</p>
      *
      * <p>For more details see <code>BeanUtilsBean</code>.</p>
      *
      * @param bean Bean whose property is to be extracted
      * @param name Simple property name of the property value to be extracted
      * @param key Lookup key of the property value to be extracted
      * @return The mapped property's value, converted to a String
      *
      * @exception IllegalAccessException if the caller does not have
      *  access to the property accessor method
      * @exception InvocationTargetException if the property accessor method
      *  throws an exception
      * @exception NoSuchMethodException if an accessor method for this
      *  property cannot be found
      * @see BeanUtilsBean#getMappedProperty(Object, String, String)
      */
     public static String getMappedProperty(Object bean,
                                            String name, String key)
             throws IllegalAccessException, InvocationTargetException,
             NoSuchMethodException {

         return BeanUtilsBean.getInstance().getMappedProperty(bean, name, key);

     }

     /**
      * <p>Return the value of the (possibly nested) property of the specified
      * name, for the specified bean, as a String.</p>
      *
      * <p>For more details see <code>BeanUtilsBean</code>.</p>
      *
      * @param bean Bean whose property is to be extracted
      * @param name Possibly nested name of the property to be extracted
      * @return The nested property's value, converted to a String
      *
      * @exception IllegalAccessException if the caller does not have
      *  access to the property accessor method
      * @exception IllegalArgumentException if a nested reference to a
      *  property returns null
      * @exception InvocationTargetException if the property accessor method
      *  throws an exception
      * @exception NoSuchMethodException if an accessor method for this
      *  property cannot be found
      * @see BeanUtilsBean#getNestedProperty
      */
     public static String getNestedProperty(Object bean, String name)
             throws IllegalAccessException, InvocationTargetException,
             NoSuchMethodException {

         return BeanUtilsBean.getInstance().getNestedProperty(bean, name);

     }

     /**
      * <p>Return the value of the specified property of the specified bean,
      * no matter which property reference format is used, as a String.</p>
      *
      * <p>For more details see <code>BeanUtilsBean</code>.</p>
      *
      * @param bean Bean whose property is to be extracted
      * @param name Possibly indexed and/or nested name of the property
      *  to be extracted
      * @return The property's value, converted to a String
      *
      * @exception IllegalAccessException if the caller does not have
      *  access to the property accessor method
      * @exception InvocationTargetException if the property accessor method
      *  throws an exception
      * @exception NoSuchMethodException if an accessor method for this
      *  property cannot be found
      * @see BeanUtilsBean#getProperty
      */
     public static String getProperty(Object bean, String name)
             throws IllegalAccessException, InvocationTargetException,
             NoSuchMethodException {

         return BeanUtilsBean.getInstance().getProperty(bean, name);

     }

     /**
      * <p>Return the value of the specified simple property of the specified
      * bean, converted to a String.</p>
      *
      * <p>For more details see <code>BeanUtilsBean</code>.</p>
      *
      * @param bean Bean whose property is to be extracted
      * @param name Name of the property to be extracted
      * @return The property's value, converted to a String
      *
      * @exception IllegalAccessException if the caller does not have
      *  access to the property accessor method
      * @exception InvocationTargetException if the property accessor method
      *  throws an exception
      * @exception NoSuchMethodException if an accessor method for this
      *  property cannot be found
      * @see BeanUtilsBean#getSimpleProperty
      */
     public static String getSimpleProperty(Object bean, String name)
             throws IllegalAccessException, InvocationTargetException,
             NoSuchMethodException {

         return BeanUtilsBean.getInstance().getSimpleProperty(bean, name);

     }

     /**
      * <p>Populate the JavaBeans properties of the specified bean, based on
      * the specified name/value pairs.</p>
      *
      * <p>For more details see <code>BeanUtilsBean</code>.</p>
      *
      * @param bean JavaBean whose properties are being populated
      * @param properties Map keyed by property name, with the
      *  corresponding (String or String[]) value(s) to be set
      *
      * @exception IllegalAccessException if the caller does not have
      *  access to the property accessor method
      * @exception InvocationTargetException if the property accessor method
      *  throws an exception
      * @see BeanUtilsBean#populate
      */
     public static void populate(Object bean, Map properties)
         throws IllegalAccessException, InvocationTargetException {

         BeanUtilsBean.getInstance().populate(bean, properties);
     }

     /**
      * <p>Set the specified property value, performing type conversions as
      * required to conform to the type of the destination property.</p>
      *
      * <p>For more details see <code>BeanUtilsBean</code>.</p>
      *
      * @param bean Bean on which setting is to be performed
      * @param name Property name (can be nested/indexed/mapped/combo)
      * @param value Value to be set
      *
      * @exception IllegalAccessException if the caller does not have
      *  access to the property accessor method
      * @exception InvocationTargetException if the property accessor method
      *  throws an exception
      * @see BeanUtilsBean#setProperty
      */
     public static void setProperty(Object bean, String name, Object value)
         throws IllegalAccessException, InvocationTargetException {

         BeanUtilsBean.getInstance().setProperty(bean, name, value);
     }

     /**
      * If we're running on JDK 1.4 or later, initialize the cause for the given throwable.
      *
      * @param  throwable The throwable.
      * @param  cause     The cause of the throwable.
      * @return  true if the cause was initialized, otherwise false.
      * @since 1.8.0
      */
     public static boolean initCause(Throwable throwable, Throwable cause) {
         return BeanUtilsBean.getInstance().initCause(throwable, cause);
     }

     /**
      * Create a cache.
      * @return a new cache
      * @since 1.8.0
      */
     public static Map createCache() {
         return new WeakFastHashMap();
     }

     /**
      * Return whether a Map is fast
      * @param map The map
      * @return Whether it is fast or not.
      * @since 1.8.0
      */
     public static boolean getCacheFast(Map map) {
         if (map instanceof WeakFastHashMap) {
             return ((WeakFastHashMap)map).getFast();
         } else {
             return false;
         }
     }

     /**
      * Set whether fast on a Map
      * @param map The map
      * @param fast Whether it should be fast or not.
      * @since 1.8.0
      */
     public static void setCacheFast(Map map, boolean fast) {
         if (map instanceof WeakFastHashMap) {
             ((WeakFastHashMap)map).setFast(fast);
         }
     }
 }