1. java中怎么创建对象数组比如我创建了一个学生类Student,怎么用这个类创建一个对象数组,麻烦给个例子
Student[] student = new Student[5];就像String是一个字符串,String[] 就是一个字符串数组,一样的意思
2. java 作业:创建一个学生类,创建一个学生列表,将五个学生对象加入到列表当中,提供一个工具类,提
//Student.java
public class Student {
private int id;
private String name;
private String grade;//班级
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 "学号 [id=" + id + ", 姓名=" + name + ", 班级=" + 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("没有学生!");
}
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,"王同学","2班");
Student stu2 = new Student(201105,"张同学","2班");
Student stu3 = new Student(201112,"张张同学","3班");
stuList.add(stu1);
stuList.add(stu2);
stuList.add(stu2);
System.out.println(new StudentUtil().getStuById(stuList,201112).toString());
}
}
3. 用java创建一个学生类 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创建一个学生类
publicclassTest{
publicstaticvoidmain(String[]args){
ArrayList<Student>studentList=newArrayList<>();
studentList.add(newStudent("张三","class1","Java",85));
studentList.add(newStudent("周乐儿","class1","C#",79));
studentList.add(newStudent("王涛","class2","C#",52));
studentList.add(newStudent("李明","class2","Java",48));
//===========================================================================
System.out.println("姓名 班级名 课程名 考试成绩");
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班的总分:"+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课程的平均分:"+javaScore/javaStudentCount+" C#课程的平均分:"+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创建两个类,一个学生类,一个班级类,怎样实现班级类中含有学生类的对象数组
通常实体类中,我们会创建子类的List对象在父类中,而非用数组,即在班级类中添加如下:
privateList<学生类>学生类s=newArrayList<学生类>();
publicget学生类s(){return班级ID;}
publicset学生类s(List<学生类>学生类s){this.学生类s=学生类s;}
//orreplacetoyourget/setmethod
不过最好的处理方式不是在班级中创建学生类的对象集,而是和数据库一样,在学生类中添加班级的ID,
privateString班级ID;
publicget班级ID(){return班级ID;}
publicset班级ID(String班级ID){this.班级=班级ID;}
或者:
private班级cls;
publicgetCls(){returncls;}
publicsetCls(班级c){this.cls=c;}
6. java创建两个学生对象的问题
代码1:s_Name = name;
代码2:System.out.println("学号:" + s_No);
代码3:s_Age = newAge;
代码4:s1.showNo();
代码5:s1.showSex();
代码6:s2.showName();
代码7:s1.showAge();
第1个学生的信息为:
学号:101
姓名:张三
性别:男
年龄:18
第2个学生的信息为:
学号:102
姓名:李四
性别:女
年龄:16
修改第1个学生的年龄:
第1个学生的年龄修改为:
年龄:24
郁闷,这个答案还有第2种答法?
7. JAVA定义了一个学生类,如何创建十个学生对象,并为每一个学生输入各自的信息。
定义一个学生类的数组,长度为10。
定义学生姓名数组,长度为10,并初始化每个学生姓名
定义学生其他信息数组,长度为10,初始化
循环中创建一个学生对象,为对象设置对应信息
8. 求具体编程步骤:使用JAVA设计Student类,并建立2个学生对象
这个100%正确的
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);//学生对象,学号11
Student lisi = new Student(22, "Li Si");//学生对象2,学号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创建一个学生类
//创建一个学生类,该类中拥有name,age等成员变量,
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)创建学生类,实现构造方法重载
public Student() {
}
public Student(String name) {
this.setName(name);
}
public Student(int age) {
this.setAge(age);
}
// 2)在某个构造方法中要求使用this()的方式调用其它构造方法
public Student(String name, int age) {
this(name);
this.setAge(age);
}
// 3)创建一个成员方法,该方法能返回姓名的长度
public int getNameLength() {
if (this.name != null) {
return this.name.length();
} else {
return 0;
}
}
// 4)创建一个成员方法,该方法能返回年龄
public int getAge() {
return this.age;
}
public void setAge(int age) {
this.age = age;
}
// 5)创建一个成员方法,该方法能返回姓名的首字符
public char getFirstCharacter() {
if ((this.name != null) && (this.name.length() > 0)) {
return this.name.toCharArray()[0];
} else {
return 0;
}
}
}
10. java 面像对象中, 定义一个学生类,可以创建五个学生对象,自动产生
import java.util.Random;
public class StudentTest {
private int number;//学生学号
private String name;//学生名称
private int age;//学生年龄
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){
//第一种自动产生学号方法:用for循环,从一开始,一一放进去对象学生学号那里
StudentTest[] student=new StudentTest[5];//五个对象数组
for(int i=0;i<student.length;i++){
student[i]=new StudentTest();//new对象
student[i].setNumber(i+1);//循环放入学号,
System.out.println(student[i].getNumber());
}
System.out.println("第二种方法");
//第二种方法,随机生成学号(前提是整数)
StudentTest[] student2=new StudentTest[5];//五个对象数组
for(int i=0;i<student.length;i++){
student2[i]=new StudentTest();//new对象
student2[i].setNumber((int)(Math.random()*100));//循环放入学号,
System.out.println(student2[i].getNumber());
}
//第三种方法,如果存在数据库中。在数据库表设置为自增属性
/*
CREATE TABLE students (
id int(5) NOT NULL auto_increment,#自增id,唯一的
name varchar(20)NOT NULL,
PRIMARY KEY (`id`)
)
*/
}
}
执行结果如下: