相关代码：

public class goods {
    private int id;
    private String name;
    private float price;
    private String desc;


    public goods(int id, String name, float price, String desc) {
        this.id = id;
        this.name = name;
        this.price = price;
        this.desc = desc;
    }

    static {

        System.out.println("这是静态代码块");
    }

    public  goods(){
        System.out.println("这是构造方法");
    }

    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 float getPrice() {
        return price;
    }

    public void setPrice(float price) {
        this.price = price;
    }

    public String getDesc() {
        return desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }

    public goods display(String desc) {
        this.desc = desc;
        System.out.println("修改后的desc为"+this.desc);
        return this;

    }

    @Override
    public String toString() {
        return "goods{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", price=" + price +
                ", desc='" + desc + '\'' +
                '}';
    }
}

相关代码：

​import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Scanner;

public class Testor {

    public static void main(String[] args) {
        Scanner si = new Scanner(System.in);
        try {
            Class a = Class.forName("goods");
           Constructor consturctor =  a.getConstructor(new Class[]{
                    int.class,String.class,float.class,String.class
            });
            goods good = (goods)consturctor.newInstance(new Object[]{
              1,"厉害",3200f,"fasdfasfsdfsd发士大夫士大夫"
           });
            Method method = a.getMethod("display",new Class[]{
               String.class
            });
            goods good1 = (goods)method.invoke(good,"我是靓仔");
            System.out.println(good1);

        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
    }
}