我正在尝试进行一项任务，我必须检查矩形是否重叠以及其他一些方法。我几乎完成了它但我无法从类中创建新对象。它给了我 错误：（121,32）java：unreported exception java.lang.Exception;必须被抓住或宣布被抛出这是我的代码
/**
* Created by Sarang on 18-10-2014.
*/
import java.awt.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.Scanner;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.io.*;
public class Rectangle {
private int upper_x, upper_y, lower_x, lower_y;
public Rectangle(int upper1, int upper2,int lower1,int lower2) throws Exception {
this.upper_x=upper1;
this.upper_y=upper2;
this.lower_x=lower1;
this.lower_y=lower2;
try {
if (upper_x > lower_x || upper_y > lower_y)
{
throw new IllegalArgumentException(); //Checking if the rectangle is valid
}
if(lower_x >500)
{lower_x=500;}
if(lower_y>500)
{lower_y=500;} //Setting the lower bounds to 500
if(upper_x<50)
{upper_x=50;}
if(upper_y<50)
{upper_y=50;}
} catch (IllegalArgumentException IAE) {
System.out.println("Invalid Rectangle");
}
}
Rectangle( Rectangle other)
{
upper_x=other.upper_x;
upper_y=other.upper_y;
lower_x=other.lower_x;
lower_y=other.lower_y;
}
public boolean overlap(Rectangle other)
{
if(upper_x<other.upper_x && upper_y<other.upper_y && lower_x>other.lower_x && lower_y>other.lower_y)
{ return false;}
if (!( lower_y < other.upper_y || upper_y > other.lower_y || lower_x < other.upper_x || upper_x > other.lower_x ))
{ return true;}
return false;
}
public boolean containedIn(Rectangle other)
{
if(upper_x<other.upper_x && upper_y<other.upper_y && lower_x>other.lower_x && lower_y>other.lower_y)
{ return true;}
if(other.upper_x<upper_x && other.upper_y<upper_y && other.lower_x>lower_x && other.lower_y>lower_y)
{
return true;
}
return false;
}
public boolean drag(int x, int y)
{
int temp_1x=upper_x;
int temp_1y=upper_y;
int temp_2x=lower_x;
int temp_2y=lower_y;
int length=lower_x-upper_x;
int height=lower_y-upper_y;
upper_x=x-length/2;
upper_y=y-height/2;
lower_x=x+length/2;
lower_x=y+height/2;
if(upper_x<50||upper_y<50||lower_x>500||lower_y>500)
{
upper_x=temp_1x;
upper_y=temp_1y;
lower_x=temp_2x;
lower_y=temp_2y;
return false;
}
return true;
}
public boolean resize(int x, int y)
{
int temp_x,temp_y;
temp_x=lower_x;
temp_y=lower_y;
lower_x=x;
lower_y=y;
if (upper_x > lower_x || upper_y > lower_y)
{
lower_x=temp_x;
lower_y=temp_y;
return false;
}
if(lower_x >500||lower_y>500)
{
lower_x=temp_x;
lower_y=temp_y;
return false;
}
return true;
}
public int getUpperX(){return upper_x;}
public int getUpperY(){return upper_y;}
public int getLowerX(){return lower_x;}
public int getLowerY(){return lower_y;}
public static void main(String[] args) throws IOException {
Rectangle rectangle1 = new Rectangle(60,70,400,400);
Rectangle rectangle2 = new Rectangle(100,100,450,450);
System.out.println("rectangle1.overlap(rectangle2):" + rectangle1.overlap(rectangle2));
System.out.println("rectangle1.containedIn(rectangle2):" +rectangle1.containedIn(rectangle2));
}
/*
*
* The code below this comment is for visual display of a 2D array of Rectangles.
* You are not supposed to make any changes or add any code below this comment.
*
*/
class showRecs extends JFrame {
public showRecs(Rectangle[] rectArr) {
// super("Display Arrays");
// Rectangle[] r1 = rt.rArr;
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
displayRecs recs = new displayRecs();
getContentPane().add(recs);
for (int i = 0; i < rectArr.length; i++) {
int w = rectArr[i].getLowerX() - rectArr[i].getUpperX();
int h = rectArr[i].getLowerY() - rectArr[i].getUpperY();
recs.addArrays(rectArr[i].getUpperX(), rectArr[i].getUpperY(), w, h);
}
pack();
setLocationRelativeTo(null);
setVisible(true);
}
}
class displayRecs extends JPanel {
private static final int frame_width = 500;
private static final int frame_height = frame_width;
private List<java.awt.Rectangle> rects = new ArrayList<java.awt.Rectangle>();
public void addArrays(int x, int y, int width, int height) {
java.awt.Rectangle rect = new java.awt.Rectangle(x, y, width, height);
rects.add(rect);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(frame_width, frame_height);
}
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
for (java.awt.Rectangle rect : rects) {
Random rand = new Random();
int R = rand.nextInt(255);
int G = rand.nextInt(255);
int B = rand.nextInt(255);
Color color = new Color(R, G, B);
g.setColor(color);
g.drawString("(" + rect.x + "," + rect.y + ")", rect.x - 45, rect.y);
int m = rect.x + rect.width;
int l = rect.y + rect.height;
int idx = rects.indexOf(rect);
g.drawString("(" + m + "," + l + ")", m + 1, l + 1);
int locx = rect.x + rect.width / 2;
int locy = rect.y + rect.height / 2;
g.drawString((String.valueOf(idx)), locx, locy);
g2.draw(rect);
}
}
}
}
我在代码中做错了什么。我还没有应用其他一些方法，但它没有在这个阶段运行
答案 0 :(得分：1)
当您的构造函数抛出异常时，您只能在捕获new的try / catch块中的Rectangle类上调用Exception
答案 1 :(得分：1)
你有：
public Rectangle(int upper1, int upper2,int lower1,int lower2) throws Exception {
^^^^^^^^^^^^^^^^^
这就是说你的Rectangle构造函数可以抛出任何类型的异常。这意味着任何调用构造函数的代码都必须处理任何类型的异常（通过捕获它或将其声明为抛出）。
看起来您的构造函数实际上只是抛出IllegalArgumentException，这是未选中的（不需要在throws子句中声明）。因此，如果您取消throws，它应该有用。
public Rectangle(int upper1, int upper2,int lower1,int lower2) {
...
答案 2 :(得分：1)
我们的基本问题是你已经宣布矩形的构造函数可以抛出一个异常（它没有这样做，所以这个声明很奇怪）。
在你的主程序中你不能实例化对象，因为这会调用构造函数 - 现在编译器知道构造函数可能抛出异常（因为你这样声明）所以它不会让你实例化实例你没有试一试 - 围绕实例化。
总而言之，我并不认为你想要抛出...构造函数声明的一部分 - 如果你为某些（未来）的原因需要这个构造函数抛出然后你必须进行适当的尝试 - 抓住声明来抓住潜在的投掷。
答案 3 :(得分：0)
你的构造函数如下所示：
public Rectangle(int upper1, int upper2,int lower1,int lower2) throws Exception
throws Exception表示它可能会抛出一个异常，这意味着调用者（这里是你的主要方法）需要try-catch它。