Java tutorial
/** * Project: skyline.service * * File Created at 2011-6-1 * $Id$ * * Copyright 1999-2100 Alibaba.com Corporation Limited. * All rights reserved. * * This software is the confidential and proprietary information of * Alibaba Company. ("Confidential Information"). You shall not * disclose such Confidential Information and shall use it only in * accordance with the terms of the license agreement you entered into * with Alibaba.com. */ package com.alibaba.doris.admin.service.impl; import java.lang.reflect.Array; import java.util.ArrayList; import java.util.Collections; import java.util.HashSet; import java.util.List; import java.util.Map; import java.util.Set; import org.apache.commons.lang.StringUtils; /** * ???? * * @author mian.hem */ public final class ValueParseUtil { public static final String DEF_NULL = "null"; public static final String DEF_EMPTY = "empty"; private ValueParseUtil() { } /** * ?,?, * * @param clazz * @return */ @SuppressWarnings("unchecked") private static <T> T getInternalDefaultValue(Class<T> clazz) { if (!clazz.isPrimitive()) { return null; } if (Short.TYPE.equals(clazz)) { return (T) Short.valueOf((short) 0); } if (Integer.TYPE.equals(clazz)) { return (T) Integer.valueOf(0); } if (Long.TYPE.equals(clazz)) { return (T) Long.valueOf(0); } if (Boolean.TYPE.equals(clazz)) { return (T) Boolean.valueOf(false); } if (Float.TYPE.equals(clazz)) { return (T) Float.valueOf(0); } if (Double.TYPE.equals(clazz)) { return (T) Double.valueOf(0); } if (Byte.TYPE.equals(clazz)) { return (T) Byte.valueOf((byte) 0); } if (Character.TYPE.equals(clazz)) { return (T) Character.valueOf('\0'); } return null; } /** * ?String ?: * * <pre> * short, int, long, float : 0 * char, byte: 0 * String: null * Map, List: null * Integer, Long, Float : null * Date: null * array: null * </pre> * * @param strValue * @param clazz * @return */ @SuppressWarnings("unchecked") public static <T> T parseStringValue(String strValue, Class<T> clazz, boolean autoDefault) { if (DEF_NULL.equals(strValue)) { if (!clazz.isPrimitive()) { return null; } if (autoDefault) { return (T) getInternalDefaultValue(clazz); } else { return null; } } if (DEF_EMPTY.equals(strValue)) { if (clazz.isArray()) { return (T) Array.newInstance(clazz.getComponentType(), 0); } if (Map.class.isAssignableFrom(clazz)) { return (T) Collections.EMPTY_MAP; } if (List.class.isAssignableFrom(clazz)) { return (T) new ArrayList<Object>(); } if (Set.class.isAssignableFrom(clazz)) { return (T) new HashSet<Object>(); } if (String.class.equals(clazz)) { return (T) StringUtils.EMPTY; } if (Character.TYPE.equals(clazz) || Character.class.equals(clazz)) { return (T) Character.valueOf(' '); } if (autoDefault) { return (T) getInternalDefaultValue(clazz); } else { return null; } } if (StringUtils.isBlank(strValue)) {// ? if (autoDefault) { return (T) getInternalDefaultValue(clazz); } else { return null; } } else { if (String.class.equals(clazz)) { return (T) strValue; } if (Short.TYPE.equals(clazz) || Short.class.equals(clazz)) { return (T) Short.valueOf(strValue); } if (Integer.TYPE.equals(clazz) || Integer.class.equals(clazz)) { return (T) Integer.valueOf(strValue); } if (Long.TYPE.equals(clazz) || Long.class.equals(clazz)) { return (T) Long.valueOf(strValue); } if (Boolean.TYPE.equals(clazz) || Boolean.class.equals(clazz)) { return (T) Boolean.valueOf(strValue); } if (Float.TYPE.equals(clazz) || Float.class.equals(clazz)) { return (T) Float.valueOf(strValue); } if (Double.TYPE.equals(clazz) || Double.class.equals(clazz)) { return (T) Double.valueOf(strValue); } if (Byte.TYPE.equals(clazz) || Byte.class.equals(clazz)) { return (T) Byte.valueOf(strValue); } if (Character.TYPE.equals(clazz) || Character.class.equals(clazz)) { return (T) Character.valueOf(strValue.charAt(0)); } if (clazz.isArray()) { final Class<?> componentType = clazz.getComponentType(); // String[] if (String.class.equals(componentType)) { return (T) StringUtils.split(strValue, ','); } // ?char[] if (Character.TYPE.equals(componentType)) { return (T) strValue.toCharArray(); } if (Character.class.equals(componentType)) { final char[] tmp = strValue.toCharArray(); final Character[] result = new Character[tmp.length]; for (int i = 0; i < result.length; i++) { result[i] = tmp[i]; } return (T) result; } if (Byte.TYPE.equals(componentType) || Byte.class.equals(componentType)) { return (T) (strValue == null ? null : strValue.getBytes()); } } } return null; } public static <T> T parseStringValue(String strValue, Class<T> clazz) { return parseStringValue(strValue, clazz, true); } }