Java Time Machine. Wang Yang

Transcription

1 Java Time Machine Wang Yang

2 Arrays binarysearch only work for sorted array!!

3 Arrays How to print the content of the Array

4 Arrays How to compare whether two arrays are equal? refer_1!= refer_2 content_1 == content_2

5 Collection interface Collection interface Set interface List interface Queue Class Class Class Class HashedSet ArrayedList LinkedList PriorityQueue

6 List List the method of List Interface add/remove/clear/contain/size toarray

7 List

8 List What s the difference between ArrayList and LinkedList Array vs Link Different Interface,Different Method Different performance

9 List What s the performance difference between ArrayList and LinkedList ArrayList: Efficient in random access of elements May enlarge backend array when append new elements (can be partly solved by setting initial capacity) Not efficient for insertion (may cause the movement of elements) Waste of space (solved by trimtosize) LinkedList Do not cause the reassignment of memory Efficient for add / delete / insert Not efficient for random access (need traverse from head) difference between ArrayList and LinkedList

10 HashMap What s the requirement of Key,Value in HashMap must be object cannot contain duplicate keys each key can map to at most one value

11 HashMap

12 iterator list the method of iterator next() hasnext()

13 Generic Type We want a data structure class for all classes Collection<E>, Map<K,V> We want a function work all classes Arrays.sort(T[] a, Comparator<? super T> c)

14 Generic Type Pseudo Generic Type Wrong, you can t assign an object to a student

15 Generic Type Implement getfirst, getsecond, swap method for Pair

16 Generic Type What s the meaning of E,K,N,T,V Type Parameter Naming Conventions single, uppercase letters E - Element (used extensively by the Java Collections Framework) K - Key N - Number T - Type V - Value S,U,V etc. - 2nd, 3rd, 4th types

17 Generic Type Bounded Type Parameter If we want specify Number ability of T for Pair<T> class Pair<T extends Number>

18 Generic Type Wildcard Lowerbound/ UpperBound/ Unbound

19 Thread Use Thread Class to define a thread and run it

20 Thread Use Runnable Interface to define a thread and run it

21 Thread State Blocked Timed Waiting new Thread(arg) New Waiting Scheduled Runnable Start() Running run() 结束 Terminated suspended by scheduler

22 Thread State Blocked Timed Waiting notify() notifyall() Waiting join() wait() New Runnable Running Terminated

23 Thread State Blocked Timeout Timed Waiting Waiting sleep() New Runnable Running Terminated

24 Thread State Acquired lock Blocked Synchronized Timed Waiting Waiting New Runnable Running Terminated

25 Thread State Blocked Timed Waiting Interrupt() Interrupted() Waiting New Runnable Running Terminated

26 Thread Synchronize When we should use synchronized When we should use wait() when multiple threads will modify the field concurrently in case of deadlock

27 Thread Synchronize class station extends Thread{ static int tickets = 200; synchronized void sell() { {tickets - -;} } public void run() {while(tickets>0) {sell();}} public static void main(string args[]){ Station stationarray[] = new Station[10]; for(int i = 0; i < 10; i++) { stationarray[i] = new Station(); } }

28 GUI What s the different Swing and AWT A4T 1JiB; DeIClCDeE 1HB JD, 1HB JD, IADleAeB GaGiCB PCEGabliGK HeaIK Jei;hGed; GCD; IBICke O1 CCADCBeBG ADDeaEaBce abd BehaIiCE dedebd CB O1 -i;hg Jei;hGed; TCD leiel ccbgaibee ibicke O1 ccadcbebg; ACFG ccadcbebg if ib DHEe jaia IBdeDeBdeBG JiGh O1 1Deed FaFG 1lCJ befcee Jdk1.4, bhg fafgee BCJ CCADCBeBG.C abhbdabg AbHBdaBG ViFHal DeIelCDAeBG.C JbHildeEL.eGbeaBFLEcliDFe VE

29 GUI What s the important elements of GUI Programming Components different components, Text, Label, Icon, Button.. Layout how to combine the component Action/Event user interaction

30 GUI Containers include Top Container JFrame,JDialog connected with OS are not contained in anything else intermediate Container JPanel manage component can be nested

31 GUI Components includes JTextField JButton JCheckBox JRadioButton.

32 GUI Layouts include BorderLayout FlowLayout GridLayout

33 GUI BorderLayout is the default layout of? BorderLayout rules JFrame EAST,WEST,NORTH,SOUTH,CENTER

34 GUI FlowLayout is the default layout of? FlowLayout rules JPanel Left to Right,Up to Down

35 GUI GridLayout Rules Row * Column Left to Right,Up to Down

36 GUI Event Programming three elements are Source : addxxxlistener handler : xxxeventlistener event

37 GUI what s Inner Class priority? An inner class gets a special pass to use the outer class' stuff. Even the private stuff. they have most of the benefits of a normal class. but with special access rights.

38 GUI What s the restriction of inner class An Inner class Must be tied to at 1 outer class instance you can t new an inner class directly outside the outer cla

39 GUI make a simple action event program ActionListener, addactionlistener, JFrame, JButton, JTextFiled

40 SQL CRUD Operation includes Create, Read, Update, Delete Create : create the table and insert data into table Read : select data from table Update : update data in the table Delete : delete data from the table

41 SQL Data ColumnName StudentName StudentID Score DataType varchar(10) char(7) int Query INSERT into Course (StudentName, StudentID, Score) VALUES ( 张 小灵, , 91) ; result

42 SQL Data Query SELECT StudentName, Score FROM Course Order by Score DESC; Result

43 SQL Data Query SELECT StudentName, Score FROM Course Where StudentName in ( 张 小灵, 李 小乐 ); Result

44 SQL Data Query UPDATE Course SET Score=95 Where StudentID= ; Result

45 SQL Data Query DELETE FROM Course Where Score>91; Result

46 SQL import java.sql.*; Load the vendor specific driver Class.forName("com.mysql.jdbc.Driver"); Dynamically loads a driver class, for Mysql database Make the connection String dburl = "jdbc:mysql://localhost:3306/" + "MyDB?user=your_username&password=your_password"; Connection connection = DriverManager.getConnection(dbURL); Establishes connection to database by obtaining a Connection object

47 SQL Statement have two execute methods, they are: ExecuteQuery ExecuteUpdate

48 Network How to identify a host in network HostName IPAddr DomainName

49 Network How to get an INetAddress Object INetAddress.getByName( ) INetAddress.getByAnem( )

50 Network There are two types of sockets, they are: ServerSocket Socket

51 Network Setup a ServerSocket at port 80

52 Network Setup a socket for port 80

53 Network How to read or write to the socket socket.getinputstream() Socket.getOutputStream()

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