1.Integer轉換成int的方法

Integer i = new Integer(10); 
int k = i.intValue();
即Integer.intValue();

2.int轉換成Integer

int i = 10;

Integer it = new Integer(i);

4.int轉換成String

int i = 10;

(1)String s = String.valueOf(i);

(2)String s = Ingeger.toString(i);

(3)String s = "" + i;

5.String轉換成Integer

String str = "10";

Integer it = Integer.valueOf(str);

6.Integer轉換成String

Integer it = new Integer(10);

String str = it.toString();

7.String轉換成BigDecimal

BigDecimal bd = new BigDecimal(str);

8.日期

Calendar calendar = Calendar.getInstance();
int year = calendar.get(Calendar.YEAR);
int month = calendar.get(Calendar.MONTH)+1;
int day = calendar.get(Calendar.DATE);

//獲取今天的日期字串
String today = java.text.DateFormat.getDateInstance().format(new java.util.Date());
//獲取今天的日期
new java.sql.Date(System.currentTimeMillis());

轉自https://www.cnblogs.com/sam-cheng/p/6520530.html