这是我写的一个类的部分内容:但ArrayList类add方法不能用,不知道为什么?
另外,我若把这部分放到Main函数中又可以用了,不知道为什么?怎样才能在mian 函数外用ArrayList类 的add方法?package adapter;
import java.util.*;public class Header {
private ArrayList<Student> students = new ArrayList<Student>();
public Header(){
}
Student s1 = new Student("1111","xu",22,"male","singing");
Student s2 = new Student("2222","guo",22,"male","running");
Student s3 = new Student("3333","jun",22,"male","jumping");
Student s4 = new Student("4444","qin",22,"male","writing");
Student s5 = new Student("5555","guan",22,"male","reading");
students.add(s1);//报错:Syntax error on token "s1", VariableDeclaratorId expected after this token void display(String ssn){
for(Student s : students){
if(s.getSsn() == ssn){
System.out.println("学号:"+s.getSsn()+"姓名:"+
s.getName()+"年龄:"+s.getAge()
+"性别:"+s.getSex()+"特长:"+s.getSpecial());
}
}
}
}
例如:
private void initList()
{
students.add(s1);
}
//
void display(String ssn){ initList();
for(Student s : students){
if(s.getSsn() == ssn){
System.out.println("学号:"+s.getSsn()+"姓名:"+
s.getName()+"年龄:"+s.getAge()
+"性别:"+s.getSex()+"特长:"+s.getSpecial());
}
}
}
记得要导入包import java.uitl.*;
所以楼主只要那个add的语句放到一个方法体{}中即可解决。