有两种方式java
Integer x = Integer.valueOf(str); // or int y = Integer.parseInt(str);
这两种方式有一点点不一样：this
valueOf返回的是java.lang.Integer的实例spa
parseInt返回的是基本数据类型 intcode
Short.valueOf/parseShort,Long.valueOf/parseLong等也是有相似差异。orm
另外还需注意的是，在作int类型转换时，可能会抛出NumberFormatException，所以要作好异常捕获input
int foo;
String StringThatCouldBeANumberOrNot = "26263Hello"; //will throw exception
String StringThatCouldBeANumberOrNot2 = "26263"; //will not throw exception
try {
foo = Integer.parseInt(StringThatCouldBeANumberOrNot);
} catch (NumberFormatException e) {
//Will Throw exception!
//do something! anything to handle the exception.
}
try {
foo = Integer.parseInt(StringThatCouldBeANumberOrNot2);
} catch (NumberFormatException e) {
//No problem this time but still it is good practice to care about exceptions.
//Never trust user input :)
//do something! anything to handle the exception.
}