It 18 Palm Seventh Day summary (including jobs)

It 18 Palm Seventh Day summary (including job) review--------Object a  subclass  AA  Subclass AAA You can use  A AA AAA  to create a new subclass   You can use either to declare abstract classes and Interfaces-------------------    all methods in an interface are abstract     abstract classes can have no abstract method   Total      cannot instantiate   internal class post-compilation member location            Local location with "$"   to interval        use numbers to interval        anonymous inner class objects------------------------      integrates inheritance of classes, method overrides, and creation of objects into one line of code.      format:        new  The external class name or interface name () {overrides the code in the class or interface, ( You can also customize the content. )}     the call to the   //function as an example of *     button btn1 = new  button ();    //an anonymous inner class object that inherits the class, overrides the method, and creates an object one go.     btn1.addlistener (New buttonlisteneradapter () {   //  btn1.addlistener  is to call the addlistener  method    the method is to have the listener interface as a parameter, and the listener for  {}  is equivalent to inheriting        &nBsp; public void onclick () {    system.out.println ("click once");} This method defines two anonymous class objects   worship btn1  and  btn2    methods [1]********************************************** When writing code, be careful that the symbol is perfect   The parentheses are written in pairs. Use  ;  end at the end of a statement ***************************************************button btn1 = new  button ();//Anonymous inner class object that inherits the class, overrides the method, and creates the object one go. Btn1.addlistener (New buttonlisteneradapter () {Public void onclick () {System.out.println ("click once");}); /Create Btn2 object, use anonymous inner class, give implementation to OnClick (), Ondbclick () two methods. Button btn2 = new button (); Btn2.addlistener (New buttonlisteneradapter () {public  Void onclick () {System.out.println ("click once");} Public void ondbclick () {System.out.println ("click two Times");}); [Method 2] Buttonlisteneradapter aa = new buttonlisteneradapter ()  {public void onclick () {System.out.println ("click once");} Public void ondbclick () {System.out.println ("click two Times");};  //attention to &NBSP;;   End two methods result same   additional buttonlisteneradapter -->  buttonlistener  (Object oriented programming) That is Buttonlisteneradapter aa = new buttonlisteneradapter ()  --> buttonlistener  aa = new buttonlisteneradapter ()   Rewrite local tyrants marriage with anonymous inner class object//define three   white, rich, beautiful interface   iwhite{   //definition white     public void  Whiteing  ();  }interface  irich{   //definition of Rich     public void   riching  ();  }interface  ibeautiful{   //definition Beauty     public  void  Beautifuling  ();  } //defines an interface that inherits white, rich, beauty   three interfaces  interface  womanstart extends iwhite,irich,ibeautiful{ } //definition local Tyrants class  class EarchRicher{                       //    public&nBsp;void marry (womanstart mm) {       system.out.println ("FIND   Mating  !! ");       }    }  class earchricherman {      public static void main (String[] args) {          womanstart w = new womanstart () {            public void  Whiteing  () {          }        public void   Riching  () {         }          public void  Beautifuling  () {          }         };      earchricher  M =new earchricher ();      m.marry (W);     } } exception ———— ————————————————————————————————    java.lang.throwable       The system of    java.lang.error java.lang.exception anomaly throwable     Error often has a major problem, such as a running class that does not exist or a memory overflow. Do not write a case for code to handle it      Exception  run at run time, you can pass the try catch  The subclass name for Finallyexception and error is the name of the parent class suffix throws used to identify the exception that the function exposes. Throw is used to throw an exception object. The difference between throws and throw:     thorws is used on the function, followed by the exception class name.     throw is used inside a function, followed by an exception object. Practice Exception Function Declaration class person{private int age;   //define function, declare exception public void setage ( Int age)  throws exception {  //throws Exception declaration if  (age < 0 | | &NBSP;AGE&NBSP;&GT;&NBSP;120) {//Throw exception throw new exception ("Age is not legal!!! ");    }this.age =  age ;   // get  set  Define Age       }    public int getage () { Return age;}} Class exceptiondemo{public static void main (String[] args) {Person pe =  new person ();                 try{                   //try  try   catch  capture    handle Exceptions        pe.setage ( }catch) (Exception ex) {   // catch () What kinds of exceptions are caught Ex.printstacktrace ();   //The trace information for the stack that prints the function}}}/*** run *        java.lang.exception:  age is not legal!!! *       at person.setage (Exceptiondemo.java:7) *        at exceptiondemo.main (exceptiondemo.java:23) **/package--------------------Package, folder. java/lang/Xxxxjar : java archieve,java archive file. Java/lang/object.class full Name Class name, complete class name  : java.lang.object  java/lang/object compile time Specify class file to store directory using the-D parameter : The Java -d xx/xxx packagedemo.java runtime specifies the directory where the class file is located using the-CP parameter:java -cp xx/xx   A visibility access rule------------------modifier publicprotecteddefaultprivate ---------------------------------------------- --------------------range of similar vvvv VVV sub-class VV different package Vjar-----------------package Java library files. []jar cvf myjar.jar -c classes/ .       the class under the Classpath to a jar file]                   // myjar.jar  the file name to be packaged as a custom//classes/is the folder where the class file is located  jar cvfe myjar.jar a.a1.a11.a111.a -c &NBSP;CLASSES/&NBSP;.//E the specified entry point.   e is the class that contains the main function [use the Java -jar parameter to run the program]java -jar myjar.jar/ /execute JAR file java -jar myjar.jara.a1.a11.a111.a//execute JAR file to specify the entry point. 2. Define the Triangle class Trianle, which contains three int type attributes, representing the length of three edges respectively, &NBSP;&NWhen constructing a triangular object, the sum of any two sides is greater than the third side and, if not, throws a custom exception. Answer:class edgetoosmallexception extends exception { //  This exception is used to determine if the side is less than or equal to 0 private  string info;public edgetoosmallexception ()  {}public edgetoosmallexception (String  info)  {this.info = info;} Public string getinfo ()  {return info;} Public void setedgeinfo (String info)  {this.info = info;}} class edgenotmatchexception extends exception { //  This anomaly is used to judge the private  of a triangle. String info;public edgenotmatchexception ()  {}public edgenotmatchexception (String info )  {this.info = info;} Public string getinfo ()  {return info;} Public void setedgenotmatchexception (String info)  {this.info = info;}} class triangle {//three-side private int edgea;private int edgeb;private int  Edgec;// edgea's Get/set method public int getedgea ()  {return edgea;} Public void setedgea (Int edgea)  throws EdgeTooSmallException {if  (Edgea  > 0)  {this.edgea = edgea;}  else {throw new edgetoosmallexception ("Edge length a cannot be less than or equal to 0");}}  edgeb Get/set Method Public int getedgeb ()  {return edgeb;} Public void setedgeb (INT&NBSP;EDGEB)  throws EdgeTooSmallException {if  (Edgeb  > 0)  {this.edgeb = edgeb;}  else {throw new edgetoosmallexception ("Edge length B cannot be less than or equal to 0");}}  edgec Get/set Method Public int getedgec ()  {return edgec;} Public void setedgec (INT&NBSP;EDGEC)  throws EdgeTooSmallException {if  (EDGEC  > 0)  {this.edgec = edgec;}  else {throw new edgetoosmallexception ("Edge length C cannot be less than or equal to 0");}}   Judging is not triangular public static void checking (int x, inT y, int z) throws edgenotmatchexception {if  (x + y <= z  | |  x + z <= y | |  y + z <= x)  {throw new edgenotmatchexception ("This is not a triangle");}  else {system.out.println ("This is a triangle");}}} Class triangledemo {public static void main (String[] args)  {//  Construct the Triangle Triangle t1 = new triangle ();//  set three edges, find the anomaly Try {t1.setedgea (4); T1.setEdgeb (5 ); T1.setedgec (3); T1. Checking (T1.getedgea (),  t1.getedgeb (), &NBSP;T1.GETEDGEC ());  catch  (edgetoosmallexception e)  {system.out.println (E.getinfo ()); System.exit (-1);}  catch  (edgenotmatchexception e)  {system.out.println (E.getinfo ()); System.exit (-1);} System.out.println ("Side length for"  + t1.getedgea ()  +  ","  + t1.getedgeb ()  +  "," + &NBSP;T1.GETEDGEC ());}} The birthday attribute is added to the 3.Person class for Setbirthday (INT&NBSP;,INT&NBsp;, int ) methods for exception handling,   requirements are valid for the year, the month is valid, the date is valid, the specified date is valid, and the different exceptions are thrown separately. A: Add the birthday attribute to the/** * person class and treat the Setbirthday (int ,int , int ) method with exception, *  The required year is valid, the month is valid, the date is valid, the date specified is valid, and different exceptions are thrown separately.  *  */public class Brithday {private String birthday;public  String getbirthday ()  {return birthday;} Public void setbirthday (int year, int month, int date) throws  invalidparamexcetion {//  judgment Year if  (year < 1900 | |  year > 2016)  {throw new invalidparamexcetion ("Year is inappropriate, please pass the year 1900 to 2016");   Judging month if  (month <= 0 | | &NBSP;MONTH&NBSP;&GT;&NBSP;12)  {throw new invalidparamexcetion ("The month is inappropriate, does not exist"  + month  +  "Month");}   Judgment Date if  (date > 31 | |  date <= 0)  {throw new invalidparamexcetion ("date inappropriate, not present" + date + " Day ");} boolean isthirdone = date == 1 | |  date == 3 | |  date == 5 | |  date == 7| |  date == 8 | |  date == 10 | |  date == 12;if  (!isthirdone && date == 31)  {throw  New invalidparamexcetion ("date not appropriate,"  + month +  "month does not exist"  + date+  "Day");} if  (month == 2 && date > 29)  {throw new  Invalidparamexcetion ("date is inappropriate, February does not exist"  + date +  "Day");} if  (year % 4 != 0 && month == 2 && date  == 29)  {throw new invalidparamexcetion ("date inappropriate,"  + year +  "is not a leap year, So February does not exist "+ date + " Day ");} System.out.println ("Birthday is:"  + year +  "year"  + month +  "Month &NBSP;&N"BSP; "  + date +  "Day  ");} Public static void main (String[] args)  throws invalidparamexcetion { Brithday person = new brithday (); Try {person.setbirthday (2015, 12, 5); Person.setbirthday (2016, 2, 29);p erson.setbirthday (2015, 2, 29);//  because the last sentence was abnormal, So will not execute this sentence person.setbirthday (2015, 3, 5);}  catch  (invalidparamexcetion e)  {}}}/** *  illegal parameter exceptions  *  */class  Invalidparamexcetion extends exception {public invalidparamexcetion (String msg)   {Super (MSG); SYSTEM.OUT.PRINTLN (msg);}} 4. Define the class to be under the specified package. Com.it18zhang, after compiling, make a jar file. A: Package Java library files. []jar cvf myjar.jar -c classes/ .jar cvfe myjar.jar  the class under the Classpath to a jar file] COM.IT18ZHANG.A&NBSP;-C&NBSP;CLASSES/&NBSP;.//E the specified entry point. [Use the Java -jar parameter to run the program]java -jar myjar.jar//execute the jar file java -jar myjar.jarcom.it18zhang.a// Executes the jar file to specify the entry point. 5Use the jar package with each other and place the CP to reuse the class. A: The answer is slightly 6. Design the program and examine the modifiers. Public -> protected -> default -> private (optional) answer:package  com.it18zhang.job.demo;public class person {protected string protectname;public  Void method_public ()  {system.out.println ("Person method_public");} Protected void method_protect () {System.out.println ("Person method_protect");} Void method_defult () {System.out.println ("Person method_defult");} Private void method_private () {System.out.println ("person method_private");}} Package com.it18zhang.job.demo;public class people {public static void main (String[] args)  {system.out.println ("class modifier permission test in the same package"); Person person = new person ();p erson.method_public ();p erson.method_protect ();p erson.method_ Defult ();//Cannot call Private//person.method_private ();}} Package com.it18zhang.job.demo2;import com.it18zhang.job.demo.Person;public class student extends person{public static void main (String[]  args)  {system.out.println ("Subclass modifier permission Test"); Student student = new student (); Student.method_public (); Student.method_protect ();// Unable to invoke Defult, Private//student.method_private ();//student.method_defult ();}} Package com.it18zhang.job.demo2;import com.it18zhang.job.demo.person;public class other  {public static void main (String[] args)  {system.out.println ("class modifier permission test in other packages"); Person person = new person ();p erson.method_public ();//cannot invoke Protect,default and private methods of classes in other packages/ /person.method_protect ();//person.method_defult ();//person.method_private ();}}

It 18 Palm Seventh Day summary (including jobs)