Java类型转换. - 爱码网

Object->Map

Map->Collection

Collection<V> values() //Map类的方法

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对象，因为大小已由数据决定。

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
Arrays.toSting() #Array->String

Java类型转换.

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);

时间->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 );

Java类型转换.

工具类

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 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 \| computeGetters(Class clazz, Map<String,String> aliasMap)
static List <FieldInfo>| computeGetters(Class clazz, Map aliasMap, boolean sorted) static Class| getClass(Type type)
static Class<?>| loadClass(String className),string>,object>