newinstancedemo2.java

金旭亮的java教案

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;

class Student {
    private String name;
    private int score; 

    public Student() {
        name = "N/A"; 
    } 

    public Student(String name, int score) { 
        this.name = name; 
        this.score = score; 
    } 

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

    public String getName() { 
        return name; 
    } 

    public int getScore() { 
        return score; 
    } 

    public String toString() {
        return name + ":" + score;
    }
}

public class NewInstanceDemo2 {
    public static void main(String[] args) {
        try {
            Class c = Class.forName("Student");
            
            // 指定参数类型
            Class[] params = new Class[2];
            // 第一个参数是String
            params[0] = String.class;
            // 第二个参数是int
            params[1]=int.class;
            // 取得对应参数列的构造函数            
            Constructor constructor = 
                             c.getConstructor(params);
            
            // 指定实参
            Object[] argObjs = new Object[2];
            argObjs[0] = "jxl";
            argObjs[1]=90;
            //创建对象
            Object obj = constructor.newInstance(argObjs);
            // 检查结果
            System.out.println(obj);
            
        } catch (ClassNotFoundException e) {
            System.out.println("找不到类");
        } catch (SecurityException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            System.out.println("没有所指定的方法");
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
    }
}