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java - 从 JSP 文本框输入矩阵？

问题描述

我正在尝试获取矩阵的输入，这是来自 JSP 页面的多维数组并打印它。我尽力了，

索引.JSP

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>TSP</title>
</head>

<body>
<h1> Matrix</h1>
<form action="tsp.jsp">
   <label>No of cities</label>
    <input type="text" name="cities">
    <label>Enter matrix</label>
    <input type="text" name="matrix">
   <button type="submit">Submit</button>

</form>
</body>
</html>

TSP.JSP

<%--
  Created by IntelliJ IDEA.
  User: Abhishek
  Date: 11/21/2018
  Time: 12:01 PM
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Display</title>
</head>
<body>
<% int city= Integer.parseInt(request.getParameter("cities"));
int matrix[][]=new int[100][100];

for ( int i=0; i<city;i++) {
    for (int j = 0; j < city; j++) {
        matrix[i][j]= Integer.parseInt(request.getParameter("matrix"));
    }
}

%>

<% out.print(city);

    for ( int i=0; i<city;i++) {
        for (int j = 0; j < city; j++) {
            out.print(matrix);
        }
    }
%>
</body>
</html>

当我输入值 city 为 4 时，matrix = 1 2 3 4 5 6 7 8 8 8 8 8 1 2 3 4 并单击提交它显示异常：

java.lang.NumberFormatException：对于输入字符串：“1 2 3 4 5 6 7 8 8 8 8 8 1 2 3 4”

这样做的目的基本上是，如果成功了，我想将这些传递给 java 类来解决旅行商问题。该程序运行良好。我想为它创建一个网络界面，但我被困在这一点上。

标签： javaarraysjspservletsjakarta-ee

解决方案

你可以试试这段代码：

public class StringToInt2dArray {

    public static void main(String [] args) {

        String s = "1 2 3 4 5 6 7 8 8 8 8 8 1 2 3 4";
        System.out.println("Input string: " + s);
        String [] ss = s.split(" ");
        System.out.println("Array of strings: " + Arrays.toString(ss));
        int [] int1d = new int [ss.length];
        for (int i = 0; i < ss.length; i++) {
            int1d [i] = Integer.parseInt(ss[i]);
        }
        System.out.println("Array of ints: " + Arrays.toString(int1d));

        int rows = 4;
        int cols = 4;
        int ints2d [][] = new int [rows][cols]; // need to know the 2d array size

        int n = 0;
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                ints2d [i][j] = int1d [n++];
            }
        }

        System.out.println("Array of ints in 2D: ");
        for (int i = 0; i < ints2d.length; i++) {
            System.out.println(Arrays.toString(ints2d [i]));
        }
    }
}


输出：

Input string: 1 2 3 4 5 6 7 8 8 8 8 8 1 2 3 4
Array of strings: [1, 2, 3, 4, 5, 6, 7, 8, 8, 8, 8, 8, 1, 2, 3, 4]
Array of ints: [1, 2, 3, 4, 5, 6, 7, 8, 8, 8, 8, 8, 1, 2, 3, 4]
Array of ints in 2D:
[1, 2, 3, 4]
[5, 6, 7, 8]
[8, 8, 8, 8]
[1, 2, 3, 4]

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