@Override
有可能出錯把toString寫成tostring,但編譯是不會出錯
package cn.fovegage.prac;
class Book{
public String tostring(){
return "書";
}
}
public class FanXing {
public static void main(String []args){
System.out.println(new Book());
}
}
----------------------------------
cn.fovegage.prac.Book@659e0bfd
使用Override
package cn.fovegage.prac;
class Book{
@Override
public String tostring(){ //提示出錯
return "書";
}
}
public class FanXing {
public static void main(String []args){
System.out.println(new Book());
}
}
正確表達
package cn.fovegage.prac;
class Book{
@Override
public String toString(){
return "書";
}
}
public class FanXing {
public static void main(String []args){
System.out.println(new Book());
}
}
@Deprecated(聲明過期操作) fun
package cn.fovegage.prac;
class Book{
@Deprecated
public void ~~fun()~~{
}
}
public class FanXing {
public static void main(String []args){
Book b = new Book();
b. ~~fun~~ ();
}
}
@SuppressWarnings(壓制警告)
正常代碼
package cn.fovegage.prac;
class Book<T>{
private T title;
public void setTitle(T title) {
this.title = title;
}
public T getTitle() {
return title;
}
}
public class FanXing {
public static void main(String []args){
Book b = new Book();
b.setTitle("Java");
}
}
非正常代碼
package cn.fovegage.prac;
class Book<T>{
@SuppressWarnings("unused")
private T title;
public void setTitle(T title) {
this.title = title;
}
}
public class FanXing {
@SuppressWarnings({ "rawtypes", "unchecked" })
public static void main(String []args){
Book b = new Book();
b.setTitle("Java");
}
}
