java一个小题目，题目在图片里，答案我写出来了一半，感觉错误很多，盲区很多，求大神指正

Question

答案：
import javax.swing.JOptionPane;

public class Student {
private static String name;
private static String id;
private float chinese;
private float math;
private float english;
public Student(String name, String id){
this.name="张三";
this.id=id;
}
public float average(){
float avg=(chinese+math+english)/3;
if(avg>90.0){
System.out.println("属于三好学生");
}
else{
System.out.println("不属于三好学生");
}
return avg;
}
public float score(){
return(chinese+math+english);
}
public boolean goodstudent(){
float avg=average();
return avg>90.0;

}
public String setName(){
    return this.name=name;
}
public String getName(){
    return name;
}
public void steId(String id){
    this.id=id;
}
//public float getChinese(){
//  return chinese;
//}
public void setChinese(float chinese){
    this.chinese=chinese;
}
public float getMath(){
    return math;
}
public void setMath(float math){
    this.math=math;
}
public float getEnglish(){
    return english;
}
public void setEnglish(float english){
    this.english=english;
}
//public String totring(){
//  return"当前学生信息为：[姓名="+name+",学号="+id+",语文成绩="+chinese+",数学成绩="+math+",英语成绩="+english+"]";

// }

public static void main(String[]args){
// StudentDemo a=new StudentDemo();
//StudentDemo b=new StudentDemo();

String chinese = JOptionPane.showInputDialog(null,"考试成绩","语文",1);
String math = JOptionPane.showInputDialog(null,"考试成绩","数学",1);
String english= JOptionPane.showInputDialog(null,"考试成绩","英语",1);
double a=Integer.parseInt(chinese);
double b=Integer.parseInt(math);
double c=Integer.parseInt(english);
double score=a+b+c;
Student s=new Student(name,id);

System.out.println("姓名: wang");
System.out.println("语文成绩 "+chinese);
System.out.println("数学成绩 "+math);
System.out.println("英语成绩 "+english);
//System.out.println("姓名: "+a.getName());
//System.out.println("学号: "+b.getId());

System.out.println("总成绩: "+score);
//System.out.println("平均成绩:"+s.score());

if(a+b+c>=270)
{
    System.out.print("该同学是三好学生");

}
}

}

}

Answer 1

这是我写的，但不是通过对话框输入成绩，你可以参考参考，若觉得可以，请采纳^_^
Student类：

public class Student {
    private String name;
    private String id;
    private float chinese;
    private float math;
    private float english;
    public Student() {
        super();
        this.name="张三";
        this.id="111111";
    }

    public Student(String name, String id) {
        super();
        this.name = name;
        this.id = id;
    }
    //总成绩
    public float score(float chinese,float math,float english){
        return chinese+math+english;
    }
    //平均成绩
    public float average(float chinese,float math,float english){
        float avg=(chinese+math+english)/3;
        return avg;
    }
    //三好学生
    public void goodstudent(float chinese,float math,float english){
        float good=average(chinese, math, english);
        if(good>90.0){
            System.out.println("你是三好学生");
        }else{
            System.out.println("你还不是三好学生哦");
        }
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public float getChinese() {
        return chinese;
    }
    public void setChinese(float chinese) {
        this.chinese = chinese;
    }
    public float getMath() {
        return math;
    }
    public void setMath(float math) {
        this.math = math;
    }
    public float getEnglish() {
        return english;
    }
    public void setEnglish(float english) {
        this.english = english;
    }

}

studentDemo类：

 import java.util.Scanner;

public class studentDemo {

    /**
     * @param args
     */
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);

        Student student = new Student("李四", "222222");
        float yuwen, shuxue, yingyu;

        System.out.println("请输入你的三科成绩，以空格隔开：");
        yuwen = s.nextInt();
        shuxue = s.nextInt();
        yingyu = s.nextInt();
        for (int i = 0; i < 3; i++) {
            if ((yuwen > 0 && yuwen <= 100) && (shuxue > 0 && shuxue <= 100)
                    && (yingyu > 0 && yingyu <= 100)) {
                System.out.println("你的姓名是：" + student.getName() + "\t" + "学号是："
                        + student.getId());
                System.out.println("你的三科成绩是：");
                System.out.println("语文：" + yuwen +"分"+ "\t" + "数学：" + shuxue +"分"+ "\t"
                        + "英语：" + yingyu+"分");
                System.out.println("你的总成绩是："
                        + student.score(yuwen, shuxue, yingyu)+"分");
                System.out.println("你的平均成绩是："
                        + student.average(yuwen, shuxue, yingyu)+"分");
                student.goodstudent(yuwen, shuxue, yingyu);
                break;
            }
        }
    }
}