1 package test;
 2
 3 import java.io.BufferedReader;
 4 import java.io.BufferedWriter;
 5 import java.io.File;
 6 import java.io.FileInputStream;
 7 import java.io.FileWriter;
 8 import java.io.IOException;
 9 import java.io.InputStreamReader;
10 import java.math.BigInteger;
11 import java.util.Scanner;
12
13 public class shu1 {
14     static String s = "";
15     static Scanner in = new Scanner(System.in);
16
17     public static void main(String[] args) throws IOException {
18
19
20         chansheng();
21         read();
22
23         //System.out.println(s);
24         String[] rang = s.split("[^(-9--10-9)]");  //按照数字的方式对读入的字符串进行划分，并存入到rang数组中
25
26
27
28 //        int value = 0;
29 //        int sum =0;
30         BigInteger value = new BigInteger("0");
31         BigInteger sum = new BigInteger(String.valueOf(rang[0]));    //将数组中的第一个值赋值给sum
32
33         //sum = Integer.parseInt(rang[0]);
34         for(int i = 0;i < rang.length;i++)
35         {
36             int a = value.compareTo(BigInteger.valueOf(0));
37             if ( a == 0 || a == -1) {
38                 //value = Integer.parseInt(rang[i]);          //当用于记录的值小于等于0时就无需对其进行相加了，此时就等于下一个值
39                 value = new BigInteger(String.valueOf(rang[i]));
40             }else {
41                 value.add(new BigInteger(String.valueOf(rang[i])));
42                 //value += Integer.parseInt(rang[i]);  //当value的值仍大于0时就继续相加
43             }
44
45             if (sum.compareTo(value) == -1) {    //用sum等于子数组的最大值，若value的值大于sum的值，则将value赋值给sum
46                 sum = value;
47             }
48         }
49
50         System.out.println("最大值为：" + sum);
51
52
53
54
55     }
56      //读取文件的方法
57      public static String read() throws IOException
58        {
59
60             FileInputStream fis = new FileInputStream("d:\\文件\\数组.txt");
61             BufferedReader br = new BufferedReader(new InputStreamReader(fis));
62             String temp = "";
63             while((temp = br.readLine()) != null)
64               s = s + temp + "\n";   //将文件中的文章都存入字符串s中
65
66             fis.close();//关闭文件
67             br.close();
68                return s;
69          }
70
71      //产生随机数，并将其写入到文件的操作
72     public static void chansheng() throws IOException
73     {
74         int n;
75         System.out.println("请输入计算的数据量");
76         n = in.nextInt();
77         File file1 = new File("d:\\文件\\数组.txt");
78         FileWriter out = new FileWriter(file1);
79         BufferedWriter bw = new BufferedWriter(out);
80         for(int i = 0;i < n ; i++)
81         {
82             //int ran = (int)(Math.random()*10000000) - (int)(Math.random()*100000000);
83             int ran = (int)(Math.random()*10000000) - (int)(Math.random()*100000000);
84             BigInteger a = new BigInteger(String.valueOf(ran));
85             //bw.write(String.valueOf(ran) + " ");
86             bw.write(String.valueOf(a) + " ");
87         }
88         bw.close();
89
90     }
91
92 }