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Java development environment and Review of Java

Java development environment and Review of Java. Eclipse TM Intergrated Development Environment (IDE). Running Eclipse:. Warning: Never check the “Use this as the default and do not ask again” box. The importance of workspace. This is where you will find all your java files.

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Java development environment and Review of Java

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  1. Java development environment and Review of Java

  2. EclipseTM Intergrated Development Environment (IDE) • Running Eclipse: Warning: Never check the “Use this as the default and do not ask again” box.

  3. The importance of workspace • This is where you will find all your java files. • You can switch from one workspace to another. • You need to define the workspace first (where you want to put your files) before click on OK

  4. EclipseTM tutorial Perspective is a set of related Views (windows) that enable a development specialist to perform specific tasks

  5. Setting up preferences in Eclipse If you did not download the JDK earlier in this tutorial, and your existing JRE does not appear in the “Installed JREs” preference, you must add it yourself.

  6. Setting up preferences in Eclipse

  7. Setting up preferences in Eclipse

  8. Create an Eclipse project From the Eclipse menu bar select File, New, Project to start the “New Project” wizard. Select “Java Project” and click “Next”.

  9. Create an Eclipse project

  10. Create a Java package • Structure in dot format: for example: com.tm.tutorial.main

  11. Create Java classes Create Application class under com.tm.tutorial.main package

  12. Create Java classes Create Application class under com.tm.tutorial.main package

  13. Implementation of Java class

  14. Implementation of Java class Generating setters and getters for attributes

  15. Implementation of Java class Generating constructors

  16. Implementation of Java class Generating constructors

  17. Compile Java Application

  18. Compile Java Application

  19. Run the application

  20. Run the application

  21. Run the application

  22. Run the application

  23. Run Application (Shorter way)

  24. Project 1 discussion

  25. Assign a file name Create a report object Call a method from Report class to produce report from the given data file Algorithm for Main class

  26. Structure of Report class -inFile -currentBook, nextBook …. Data members FileInput Book Report object +printReport -processBook -processGenre -columnHeadings -padL -padR Methods

  27. Printing heading Read a record false Record != null ? true Algorithm for printing a report (Report.java) Open file Print footer of the report processing genre*

  28. Print information about a book Total price for each genre += price of the current book true Is another book has the same genre ? Read another book false Algorithm for process a book and a genre currentBook = record just read Current genre = genre of the current book Start a new genre and go back to processing a new genre

  29. Class exercise • Class • Object • Primitive Data Type • If, Switch • While, Do-While

  30. Import Statements Class Comment Class Name class { Data Members Methods (incl. Constructor) } Review of Java fundamentals Template for Class Definition

  31. Import Statements Class Comment Class Name class { Data Members Methods (incl. Constructor) } Review of Java fundamentals Template for Class Definition

  32. Numeric data Variable declaration: <data type> <variable_name>; If more than one variable has the same data type: <data type> <name1>, <name2>..;

  33. Six numerical data types • byte: -128 to 127 • short:-32768 to 32767 (-215 to 215-1) • int: -231 to 231-1 • long: -263 to 263-1 • float: -3.4E+38 to 3.4E+38 • double:-1.797E+308 to 1.797E+308

  34. Assignment statement <variable name> = <expression>; Example: x =2*5+6-1;

  35. Variable names • It must be a legal identifier which is an unlimited series of characters that begins with a letter. • It must not be a keyword, a boolean literal (true or false), or the reserved word null. • It must be unique within its scope.

  36. Variable name (cont.) • Legal identifier:be composed of letters, numbers, _ and $. Identifiers may only begin with a letter, _, or $. • Keyword: http://java.sun.com/docs/books/tutorial/java/nutsandbolts/_keywords.html • Variable names begin with a lowercase letter • Class names begin with an uppercase letter

  37. Constant and variables • Constant: • Value it contains doesn’t change final int MONTHS_IN_YEAR = 12; • Variables: • Value it contains may vary double loanAmount; • loanAmount =0; • loanAmount = 1000.99;

  38. Integer division and type casting • Integer division: • Integer/integer = integer, 7/2 = 3 • Integer/double = double, 7/2.0 = 3.5 • Double/integer = double, 7.0/2 = 3.5 • Type casting: a process that converts a value of one data type to another data type.Implicit casting Explicit casting

  39. Type casting (cont.) • Implicit casting: • Operand is converted from a lower to a higher precision • Higher precision: a data type with a larger range of values • Double has a higher precision than float • Int has a higher precision than short • Operand: can be a constant, variable, method call or another arithmetic expression

  40. Type casting (cont.) • Explicit casting • (<data type>) <expression> • Example: float result; result = (float) ((3+5)/6); and result = ((float) (5+3))/6;

  41. Simple Choice Statement if (<boolean expression>) <block>; else <block>; if (<boolean expression>) single statement; else single statement;

  42. Boolean expression • Boolean expression: is a conditional expression that is evaluated to either true or false. • Conditional expression: is a three part expression: <exp.> <relational operators> <exp.> • Boolean expressions can be combined by boolean operators

  43. Relational Operators

  44. Boolean operators && means AND || means OR ! means NOT

  45. The While Loop while(<boolean expression>){ // Repeat multiple statements. statement 1 statement 2 statement 3 ... }

  46. The Do Loop do{ // Repeat multiple statements. statement 1 statement 2 statement 3 ... } while(<boolean expression); • Note that the statements in the body of the loop are always executed at least one. • Note the final semicolon, which is required.

  47. The For-Loop Outline // Repeat multiple statements. for(initialization; condition; post-body update){ // Statements to be repeated. statement 1 statement 2 statement 3 ... } • Commonly used with increment • and decrement operators.

  48. Increment and Decrement • Used as a shorthand for add-one-to and subtract-one-from: • value = value+1; • value += 1; • value++; • Prefix and postfix forms: • ++value; • --value; • value--;

  49. <modifiers> <data type> <name> ; Attributes (Data Member) Declaration Modifiers Data Type Name • private String ownerName ; Note: There’s only one modifier in this example.

  50. <modifier> <return type> <method name> ( <parameters> ){ • <statements> • } Method Declaration Modifier Return Type Method Name Parameter • public void setOwnerName ( String name ){ • ownerName = name; • } Statements

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