Java类型转换.

Object->Map

Array->List

String[] atp = {"Rafael Nadal", "Novak Djokovic",
                "Stanislas Wawrinka",
                "David Ferrer", "Roger Federer",
                "Andy Murray", "Tomas Berdych",
                "Juan Martin Del Potro"};
List<String> players = Arrays.asList(atp);

->Array

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

->String

String.copyValueOf(charArray) #Array->String

Date -> String

//如果希望得到YYYYMMDD的格式
SimpleDateFormat sy1=new SimpleDateFormat("yyyyMMDD");
String dateFormat=sy1.format(date);

//如果希望分开得到年，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);

->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 );

时间->String

V_DATE = reportdate.toString();

工具类

com.alibaba.fastjson.util.TypeUtils

Java类型转换.

原文：https://www.cnblogs.com/liehen2046/p/11061358.html