1. java中怎麼創建對象數組比如我創建了一個學生類Student,怎麼用這個類創建一個對象數組,麻煩給個例子
Student[] student = new Student[5];就像String是一個字元串,String[] 就是一個字元串數組,一樣的意思
2. java 作業:創建一個學生類,創建一個學生列表,將五個學生對象加入到列表當中,提供一個工具類,提
//Student.java
public class Student {
private int id;
private String name;
private String grade;//班級
public Student(){}
public Student(int id, String name, String grade) {
super();
this.id = id;
this.name = name;
this.grade = grade;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getGrade() {
return grade;
}
public void setGrade(String grade) {
this.grade = grade;
}
@Override
public String toString() {
return "學號 [id=" + id + ", 姓名=" + name + ", 班級=" + grade
+ "]";
}
}
//StudentUtil.java
import java.util.*;
public class StudentUtil {
public Student getStuById( List<Student> stuList ,int id){
Student student = new Student();
if(stuList!=null){
Iterator<Student> iterator = stuList.iterator();
while(iterator.hasNext()){
student = iterator.next();
if(student.getId()==id){
return student;
}
}
}
else{
System.out.println("沒有學生!");
}
return student;
}
}
//Test.java
import java.util.ArrayList;
import java.util.List;
public class Test {
public static void main(String[] args) {
// TODO Auto-generated method stub
List<Student> stuList = new ArrayList<Student>();
Student stu1 = new Student(201101,"王同學","2班");
Student stu2 = new Student(201105,"張同學","2班");
Student stu3 = new Student(201112,"張張同學","3班");
stuList.add(stu1);
stuList.add(stu2);
stuList.add(stu2);
System.out.println(new StudentUtil().getStuById(stuList,201112).toString());
}
}
3. 用java創建一個學生類 急急急
public class TestStu {
/**
* @param args
*/
public static void main(String[] args) {
Student s1 = new Student("001","Jack",56,70,80);
Student s2 = new Student("007","Lucy",90,80,70);
float result1 = s1.getChinese()+s1.getEnglish()+s1.getMath();
float result2 = s2.getChinese()+s2.getEnglish()+s2.getMath();
if(result1>result2){
System.out.println(s1.toString());
}else{
System.out.println(s2.toString());
}
}
}
class Student{
private String id;
private String name;
private float chinese;
private float english;
private float math;
public Student(){}
public Student(String id,String name,float chinese,float english,float math){
this.id=id;
this.name=name;
this.chinese=chinese;
this.english=english;
this.math=math;
}
public float getChinese() {
return chinese;
}
public void setChinese(float chinese) {
this.chinese = chinese;
}
public float getEnglish() {
return english;
}
public void setEnglish(float english) {
this.english = english;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public float getMath() {
return math;
}
public void setMath(float math) {
this.math = math;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String toString(){
return "id:"+id+"\n name:"+"\n chinese:"+chinese+"\n english:"+english+"\n math:"+math;
}
}
4. Java創建一個學生類
publicclassTest{
publicstaticvoidmain(String[]args){
ArrayList<Student>studentList=newArrayList<>();
studentList.add(newStudent("張三","class1","Java",85));
studentList.add(newStudent("周樂兒","class1","C#",79));
studentList.add(newStudent("王濤","class2","C#",52));
studentList.add(newStudent("李明","class2","Java",48));
//===========================================================================
System.out.println("姓名 班級名 課程名 考試成績");
for(Studentstudent:studentList){
System.out.println(student);
}
//===========================================================================
floatclass1SumScore=0;
intclass1StudentCount=0;
for(Studentstudent:studentList){
if(student.isClass1()){
class1SumScore+=student.getScore();
class1StudentCount++;
}
}
System.out.println(" class1班的總分:"+class1SumScore+" 平均分:"+class1SumScore/class1StudentCount);
//===========================================================================
floatjavaScore=0;
floatjavaStudentCount=0;
floatcSharpScore=0;
floatcSharpStudentCount=0;
for(Studentstudent:studentList){
if(student.isJava()){
javaScore+=student.getScore();
javaStudentCount++;
}elseif(student.isCSharp()){
cSharpScore+=student.getScore();
cSharpStudentCount++;
}
}
System.out.println(" Java課程的平均分:"+javaScore/javaStudentCount+" C#課程的平均分:"+cSharpScore/cSharpStudentCount);
}
}
classStudent{
privateStringname;
privateStringclassName;
privateStringcourseName;
privateintscore;
publicStudent(Stringname,StringclassName,StringcourseName,intscore){
this.name=name;
this.className=className;
this.courseName=courseName;
this.score=score;
}
publicbooleanisClass1(){
return"class1".equals(className);
}
publicbooleanisJava(){
return"Java".equals(courseName);
}
publicbooleanisCSharp(){
return"C#".equals(courseName);
}
publicStringgetName(){
returnname;
}
publicStringgetClassName(){
returnclassName;
}
publicStringgetCourseName(){
returncourseName;
}
publicintgetScore(){
returnscore;
}
@Override
publicStringtoString(){
returnname+" "+className+" "+courseName+" "+score;
}
}
5. 用JAVA創建兩個類,一個學生類,一個班級類,怎樣實現班級類中含有學生類的對象數組
通常實體類中,我們會創建子類的List對象在父類中,而非用數組,即在班級類中添加如下:
privateList<學生類>學生類s=newArrayList<學生類>();
publicget學生類s(){return班級ID;}
publicset學生類s(List<學生類>學生類s){this.學生類s=學生類s;}
//orreplacetoyourget/setmethod
不過最好的處理方式不是在班級中創建學生類的對象集,而是和資料庫一樣,在學生類中添加班級的ID,
privateString班級ID;
publicget班級ID(){return班級ID;}
publicset班級ID(String班級ID){this.班級=班級ID;}
或者:
private班級cls;
publicgetCls(){returncls;}
publicsetCls(班級c){this.cls=c;}
6. java創建兩個學生對象的問題
代碼1:s_Name = name;
代碼2:System.out.println("學號:" + s_No);
代碼3:s_Age = newAge;
代碼4:s1.showNo();
代碼5:s1.showSex();
代碼6:s2.showName();
代碼7:s1.showAge();
第1個學生的信息為:
學號:101
姓名:張三
性別:男
年齡:18
第2個學生的信息為:
學號:102
姓名:李四
性別:女
年齡:16
修改第1個學生的年齡:
第1個學生的年齡修改為:
年齡:24
郁悶,這個答案還有第2種答法?
7. JAVA定義了一個學生類,如何創建十個學生對象,並為每一個學生輸入各自的信息。
定義一個學生類的數組,長度為10。
定義學生姓名數組,長度為10,並初始化每個學生姓名
定義學生其他信息數組,長度為10,初始化
循環中創建一個學生對象,為對象設置對應信息
8. 求具體編程步驟:使用JAVA設計Student類,並建立2個學生對象
這個100%正確的
public class Student {
private int id;
private String name;
private char sex;
private int age;
public Student(){
}
public Student(int id){
this.id = id;
}
public Student(int id, String name){
this.id = id;
this.name =name;
}
public static void main(String[] args) {
Student zhangsan = new Student(11);//學生對象,學號11
Student lisi = new Student(22, "Li Si");//學生對象2,學號22,姓名li si
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public char getSex() {
return sex;
}
public void setSex(char sex) {
this.sex = sex;
}
}
9. JAVA創建一個學生類
//創建一個學生類,該類中擁有name,age等成員變數,
public class Student {
private String name;
private int age;
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
// 要求 1)創建學生類,實現構造方法重載
public Student() {
}
public Student(String name) {
this.setName(name);
}
public Student(int age) {
this.setAge(age);
}
// 2)在某個構造方法中要求使用this()的方式調用其它構造方法
public Student(String name, int age) {
this(name);
this.setAge(age);
}
// 3)創建一個成員方法,該方法能返回姓名的長度
public int getNameLength() {
if (this.name != null) {
return this.name.length();
} else {
return 0;
}
}
// 4)創建一個成員方法,該方法能返回年齡
public int getAge() {
return this.age;
}
public void setAge(int age) {
this.age = age;
}
// 5)創建一個成員方法,該方法能返回姓名的首字元
public char getFirstCharacter() {
if ((this.name != null) && (this.name.length() > 0)) {
return this.name.toCharArray()[0];
} else {
return 0;
}
}
}
10. java 面像對象中, 定義一個學生類,可以創建五個學生對象,自動產生
import java.util.Random;
public class StudentTest {
private int number;//學生學號
private String name;//學生名稱
private int age;//學生年齡
public int getNumber() {
return number;
}
public void setNumber(int number) {
this.number = number;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public static void main(String[] args){
//第一種自動產生學號方法:用for循環,從一開始,一一放進去對象學生學號那裡
StudentTest[] student=new StudentTest[5];//五個對象數組
for(int i=0;i<student.length;i++){
student[i]=new StudentTest();//new對象
student[i].setNumber(i+1);//循環放入學號,
System.out.println(student[i].getNumber());
}
System.out.println("第二種方法");
//第二種方法,隨機生成學號(前提是整數)
StudentTest[] student2=new StudentTest[5];//五個對象數組
for(int i=0;i<student.length;i++){
student2[i]=new StudentTest();//new對象
student2[i].setNumber((int)(Math.random()*100));//循環放入學號,
System.out.println(student2[i].getNumber());
}
//第三種方法,如果存在資料庫中。在資料庫表設置為自增屬性
/*
CREATE TABLE students (
id int(5) NOT NULL auto_increment,#自增id,唯一的
name varchar(20)NOT NULL,
PRIMARY KEY (`id`)
)
*/
}
}
執行結果如下: