关于Java纸质考试被迫背单词

构造方法

public class ClassName{
  (public) ClassName(参数列表){
  }
}

继承

public class Child extends Father{

}

接口

1.实现
public class ClassName implements Interface{

}

2.自定义接口
public interface MyInterface{
//只有抽象类和常量
}

比较器

1.内部比较器
public class ClassName implements Comparable<Object>{
    public ClassName{

    }
    public int compareTo(Object o){
        return this.-o.;//升序
    }
}
Collections.sort(array);

2.外部比较器
public class MyComparator implements Comparator<Object>{
    public int compare(Object first,Object second){
        return first.-second.;//升序
        //String类型就用(first.).compareTo(second.)
    }
}
Collections.sort(array,new MyComparator());

3.匿名内部类
Collections.sort(array,new Comparator<Object>{
    public int compare(Object first,Object second){
        return first.-second.;
    }
});

4.Lambda
Collections.sort(array,(first,second)->{
    return frist.-second.
});

异常

1.try...catch..finally
try{

}catch(Exception e){
    e.printStackTrace();
}finally{

}

2.throws
public static void method()throws Exception{

}

3.thow自定义异常,再由方法throws抛出,再由 try..catch 处理
public class MyException extends Exception{//必须继承
    public MyException(String message){
        super(message);
    }
}
public static void method()throws MyException {
    throw new MyException("这是一个异常");
}

集合

1.ArrayList
List<Object> arr = new ArrayList<Object>();

2.HashMap
Map<Type,Type> hm = new HashMap<Type,Type>()//多态的

3.Iterator
Iterator<Object>iterator = list.iterator();

4.迭代器遍历
while(iterator.hasNext()){
    ...
    String point=iterator.next();
}

5.ListIterator
ListIterator<String> listIterator=list.listIterator();

6.遍历
while(listIterator.hasNext()){
...
String point=listIterator.next();
}

7.反向遍历
while(listIterator.hasPrevious()){
...
String point=listIterator.previous();
}

流与文件

1.FileInputStream
FileInputStream fis=new FileInputStream("filename");

2.FileOutputStream,注意异常处理throws IOEXception(流这边都能用)
public static void main(String[] args) throws FileNotFoundException {
    FileOutputStream fos=new FileOutputStream(new File("filename"));
    =
    FileOutputStream fos=new FileOutputStream("filename");
}

3.Reader
Reader reader=new FileReader("filename");

4.Writer
Writer writer=new FileWriter("filename");

线程

1.实现Runnable接口
public class MyRunnable implements Runnable{
    public void run(){
    }
}

Thread thread = new Thread(new MyRunnable());
thread.start();

2.同步代码块+wait+notify
private static Object object = new Object();//static不能少
public void run(){
    ...
    synchronized(object){
        try{
            object.wait();
            或者
            object.notify();
        }catch(InterruptedException e){
            e.printStackTrace();
        }
    }
        ...
}
也可以
public synchronized void run{
    后面就不用再写syn
}