Java類型轉換.

Object->Map

Map->Collection

Collection<V> values() //Map類的方法

Array->List

import org.apache.commons.collections.CollectionUtils;
CollectionUtils.addAll(strList, strArray);  
CollectionUtils.addAll(strSet, strArray);
---
List<String> players = Arrays.asList(strArray); //注:此playersList不能add或remove對象，由於大小已由數據決定。

Set <-> List

List<String> result = new ArrayList<>(mySet);
Set result = new HashSet(myList);

->Array

Collection.toArray() 
/*ArrayList ，EnumSet ， HashSet ，LinkedHashSet ， LinkedList ， Stack ， TreeSet ， Vector */

->String

String.copyValueOf(charArray) #Array->String

Date -> String

//若是但願獲得YYYYMMDD的格式
SimpleDateFormat sy1=new SimpleDateFormat("yyyyMMDD");
String dateFormat=sy1.format(date);

//若是但願分開獲得年，月，日
SimpleDateFormat sy=new SimpleDateFormat("yyyy");
SimpleDateFormat sm=new SimpleDateFormat("MM");
SimpleDateFormat sd=new SimpleDateFormat("dd");
String syear=sy.format(date);
String smon=sm.format(date);
String sday=sd.format(date);

//String -> Date
String reportdate_str ="2005-10-01";
reportdate_str = reportdate_str + "00:00:00.0";
Date reportdate = java.sql.Timestamp.valueOf(reportdate_str);

時間->String

V_DATE =  reportdate.toString();

->int、double、other

//int
Integer.parseInt(String s)
int i = Double.intValue();
Character.getNumericValue('a');

//double
(new Float(100.00f)).doubleValue();
Double.valueOf("32.1").doubleValue();
Double d = Double.parseDouble( s );

//other
byte b = Byte.parseByte( s );
short t = Short.parseShort( s );
long l = Long.parseLong( s );
Float f = Float.parseFloat( s );

工具類

com.alibaba.fastjson.util.TypeUtils

Method Summary	-
static void	addBaseClassMappings()
static void	addClassMapping(String className, Class<?> clazz)
static T	cast(Object obj, Class clazz, ParserConfig mapping)
static T	cast(Object obj, ParameterizedType type, ParserConfig mapping)
static T	cast(Object obj, Type type, ParserConfig mapping)
static BigDecimal	castToBigDecimal(Object value)
static BigInteger	castToBigInteger(Object value)
static Boolean	castToBoolean(Object value)
static Byte	castToByte(Object value)
static byte[]	castToBytes(Object value)
static Character	castToChar(Object value)
static Date	castToDate(Object value)
static Double	castToDouble(Object value)
static T	castToEnum(Object obj, Class clazz, ParserConfig mapping)
static Float	castToFloat(Object value)
static Integer	castToInt(Object value)
static T	castToJavaBean(Map<String,Object> map, Class clazz, ParserConfig mapping)
static T	castToJavaBean(Object obj, Class clazz)
static Long	castToLong(Object value)
static Short	castToShort(Object value)
static Date	castToSqlDate(Object value)
static String	castToString(Object value)
static Timestamp	castToTimestamp(Object value)
static void	clearClassMapping()
static List <FieldInfo>	computeGetters(Class<?> clazz, Map<String,String> aliasMap)
static List <FieldInfo>	computeGetters(Class<?> clazz, Map<String,String> aliasMap, boolean sorted)
static Class<?>	getClass(Type type)
static Class<?>	loadClass(String className)