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{
}
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.;
}
}
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.;
}
}
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{
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>()
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();
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
}