public class Box { int x1,y1,x2,y2=0; Box buildBox(int x1,int y2,int x2,int y2){ this.x1=x1; this.y1=y1; this.x2=x2; this.y2=y2; return this; } Box buildBox(Point topLeft,Point bottomRight){ x1=topLeft.x; y1=topLeft.y; x2=bottomRight.x; y22=bottomRight.y; return this; } Box buildBox(Point topLeft,int w,int h){ x1=topLeft.x; y2= topLeft.y; x2=(x1+w); y2=(y1+h); return this; } void printBox(){ System.out.println("Box:<"+x1+","+y1); System.out.println(","+x2+","+y2+" > "); } public static void main(String[] args) { rect.buildBox(25,25,50,50); rect.printBox(); rect.buildBox(new Point(10,10),new Point(20,20)); rect.printBox(); rect.buildBox(new Point(10,10),50,50); rect.printBox(); } }

这段代码有一些问题，主要是方法中的参数名和后面的变量名不一致，导致编译错误。以下是修改后的代码：

import java.awt.Point;

public class Box {
    int x1, y1, x2, y2 = 0;

    public Box buildBox(int x1, int y1, int x2, int y2) {
        this.x1 = x1;
        this.y1 = y1;
        this.x2 = x2;
        this.y2 = y2;
        return this;
    }

    public Box buildBox(Point topLeft, Point bottomRight) {
        x1 = topLeft.x;
        y1 = topLeft.y;
        x2 = bottomRight.x;
        y2 = bottomRight.y;
        return this;
    }

    public Box buildBox(Point topLeft, int w, int h) {
        x1 = topLeft.x;
        y1 = topLeft.y;
        x2 = (x1 + w);
        y2 = (y1 + h);
        return this;
    }

    public void printBox() {
        System.out.println("Box:<" + x1 + "," + y1);
        System.out.println("," + x2 + "," + y2 + " > ");
    }

    public static void main(String[] args) {
        Box rect = new Box();
        rect.buildBox(25, 25, 50, 50);
        rect.printBox();
        rect.buildBox(new Point(10, 10), new Point(20, 20));
        rect.printBox();
        rect.buildBox(new Point(10, 10), 50, 50);
        rect.printBox();
    }
}

在 main 方法中，我们需要先创建一个 Box 的实例对象才可以调用其它方法。另外，建议将类名的首字母大写以符合 Java 命名规范。