1.Integer转换成int的方法

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

2.int转换成Integer

int i;

Integer it = new Integer(i);

3.String转换成int的方法

String str = "10";  
Integer it = new Interger(str);  

int i = it.intValue();  

即：int i = Integer.intValue(string);

4.int转换成String

int i;

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

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

(3)String s = "" + i;

5.String转换成Integer

String str = "10"

Integer it = Integer.valueOf(str);

6.Integer转换成String

Integer it;

String str = it.toString();

7.String转换成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);

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