Java的Set方法
我是java新手,我创建了一个set方法书参考号,所以它只接受3个字符。我尝试了下面的代码,但不正确Java的Set方法,java,Java,我是java新手,我创建了一个set方法书参考号,所以它只接受3个字符。我尝试了下面的代码,但不正确 public void setRefNumber(String ref) { System.out.println("hello " + ref()); if(ref.length() ==3) { return; } System.out.println("Fail...Your reference number mis too short"); }
public void setRefNumber(String ref)
{
System.out.println("hello " + ref());
if(ref.length() ==3)
{
return;
}
System.out.println("Fail...Your reference number mis too short");
}
输出:
hello 123
hello 1234
Fail...Your reference number 12 is too short
Fail...Your reference number aa is too short
试试看,ref是一个变量,而不是一个方法。所以ref应该是ref。
此外,在当前实例中不设置ref字段。
根据输出中的信息,如果3太短:
System.out.println("Fail...Your reference number mis too short");
您应该执行您的方法返回,而不执行任何操作。执行返回语句之前必须执行的操作。另外,如果同时提供if和else部分,则在方法类型已为void时不必使用return
public void setRefNumber(String ref) {
// it could be null too
if ( ref == null ) {
System.out.println("Cannot be null);
return;
}
System.out.println("hello " + ref);
if(ref.length() == 3) {
// set ref here
System.out.println("Success");
// return;
} else {
System.out.println("Fail...Your reference number is too short/long");
}
}
就像其他人指出的那样。ref是变量而不是方法。使用ref而不是ref。打印语句中的ref是什么?
private String ref;
public void setRefNumber(String ref) {
System.out.println("hello " + ref);
if(ref.length() < 3){
System.out.println("Fail...Your reference number mis too short");
return;
}
this.ref=ref;
}
public void setRefNumber(String ref) {
// it could be null too
if ( ref == null ) {
System.out.println("Cannot be null);
return;
}
System.out.println("hello " + ref);
if(ref.length() == 3) {
// set ref here
System.out.println("Success");
// return;
} else {
System.out.println("Fail...Your reference number is too short/long");
}
}