int ?i? = ? 7 ;
double ?d? = ? 13.56 ;
String?str1,str2;
str1? = ?Integer.toString(i);
str2? = ?Double.toString(d);
執行以后，str1存的字符串是 " 7 " ,str2存的字符串是 " 13.56 " .

String?str1? = ? " 3532 " ;
String?str2? = ? " 187.863 " ;

Integer?m;
Double?n;

m? = ?Integer.valueOf(str1);???? // 將String類型轉換成Integer類型
n? = ?Integer.valueOf(str2);????? // 將String類型轉換成Double?類型

int ?i? = ?m.intValue();??????????????? // 將Integer類型轉換成int類型
double ?d? = ?n.doubleValue();?

執行以后，整型變量i為3532，浮點型變量為187. 863

String?str1? = ? " 3532 " ;
String?str2? = ? " 187.863 " ;

int ?i? = ?Integer.praseInt(str1);
double ?d? = ?Double.praseDouble(str2);

執行以后，整型變量i為3532?，浮點型變量d為187. 863

// 把字符串轉化成日期類型
import ?java.sql.Date;
???????Date?date? = ? new ?Date( 0 );
???????date.valueOf( " 1983-09-09 " );


// 把日期類型轉換成字符串類型
import ?java.sql.Date;
????????Date?date? = ? new ?Date( 0 );
???????date.valueOf( " 1983-09-09 " ).toString();

int ?i?＝ 0 ;
Integer?temp? = ? new ?Integer(?i?);