你的问题我在CSDN上看啦下
当传入常数时，会被当作int处理，例如：
[java] view plaincopyprint?public class Test {
void f(char i){System.out.println("arg is char!");};
void f(byte i){System.out.println("arg is byte!");};
void f(short i){System.out.println("arg is short!");};
void f(int i){System.out.println("arg is int!");};
void f(long i){System.out.println("arg is long!");};
void f(float i){System.out.println("arg is float!");};
void f(double i){System.out.println("arg is double!");};
public static void main(String[] args) {
// TODO Auto-generated method stub
Test t = new Test();
t.f(5);
}
}
public class Test {
void f(char i){System.out.println("arg is char!");};
void f(byte i){System.out.println("arg is byte!");};
void f(short i){System.out.println("arg is short!");};
void f(int i){System.out.println("arg is int!");};
void f(long i){System.out.println("arg is long!");};
void f(float i){System.out.println("arg is float!");};
void f(double i){System.out.println("arg is double!");};
public static void main(String[] args) {
// TODO Auto-generated method stub
Test t = new Test();
t.f(5);
}
}
结果会是 arg is int!
那如果没有int形式的参数呢？重载类型会自动提高，例如：
[java] view plaincopyprint?public class Test {
void f(char i){System.out.println("arg is char!");};
void f(byte i){System.out.println("arg is byte!");};
void f(short i){System.out.println("arg is short!");};
//void f(int i){System.out.println("arg is int!");};
void f(long i){System.out.println("arg is long!");};
void f(float i){System.out.println("arg is float!");};
void f(double i){System.out.println("arg is double!");};
public static void main(String[] args) {
// TODO Auto-generated method stub
Test t = new Test();
t.f(5);
}
}
public class Test {
void f(char i){System.out.println("arg is char!");};
void f(byte i){System.out.println("arg is byte!");};
void f(short i){System.out.println("arg is short!");};
//void f(int i){System.out.println("arg is int!");};
void f(long i){System.out.println("arg is long!");};
void f(float i){System.out.println("arg is float!");};
void f(double i){System.out.println("arg is double!");};
public static void main(String[] args) {
// TODO Auto-generated method stub
Test t = new Test();
t.f(5);
}
}
结果会是 arg is long!
其他情况类似，会一直提升类型直到能匹配到为止，例如从byte提高到了double：
[c-sharp] view plaincopyprint?public class Test {
void f(char i){System.out.println("arg is char!");};
//void f(byte i){System.out.println("arg is byte!");};
//void f(short i){System.out.println("arg is short!");};
//void f(int i){System.out.println("arg is int!");};
//void f(long i){System.out.println("arg is long!");};
//void f(float i){System.out.println("arg is float!");};
void f(double i){System.out.println("arg is double!");};
public static void main(String[] args) {
// TODO Auto-generated method stub
byte x = 0;
Test t = new Test();
t.f(x);
}
}
public class Test {
void f(char i){System.out.println("arg is char!");};
//void f(byte i){System.out.println("arg is byte!");};
//void f(short i){System.out.println("arg is short!");};
//void f(int i){System.out.println("arg is int!");};
//void f(long i){System.out.println("arg is long!");};
//void f(float i){System.out.println("arg is float!");};
void f(double i){System.out.println("arg is double!");};
public static void main(String[] args) {
// TODO Auto-generated method stub
byte x = 0;
Test t = new Test();
t.f(x);
}
}
结果会是 arg is double!
char比较特殊，如果匹配不到会提升至int，如果还匹配不到则继续提升。
那如果传入参数的类型大于形参呢？答案是编译器会告诉你此路不通
我给你看个自动提升的表，你思考下吧~呵呵，加油兄弟
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