编辑：是的，我知道ScanObj不是一个正确的名称。这是我的所有代码。它不完整所以有一些错误和一些故障，但你要求它：
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.Scanner;
import javax.swing.JFrame;
public class MainClass {
static String[][] medium = new String[5][4];
static String names[] = { "Gatz ", "Cat ", "Women", "Mice ", "Robin",
"Romeo ", "Summer ", "Tempest", "Hamlet ", "Lear ",
"Titanic ", "StarWars", "DieHard ", "Elf ", "RED " };
static String lexile[] = { "L:1070", "L:123 ", "L:9254", "L:1234",
"L:534 ", "L:349", "L:632 ", "L:1097", "L:6453", "L:812 ",
"L:NA ", "L:NA ", "L:NA ", "L:NA ", "L:NA ", "L:NA " };
static String grade[] = { "G:9", "G:10", "G:12", "G:11", "G:9", "G:12",
"G:11", "G:9", "G:9", "G:12", "G:12", "G:11", "G:11", "G9", "G:9" };
static int max = 4;
char sorttype = (Character) null;
public static void main(String args[]) throws InterruptedException {
System.
out.println("Would you like to browse:\nB)Book C)CD or D)DVD");
Scanner ScanObj =
new Scanner(System.in);
String[] input =
new String[10];
input[1] = ScanObj.nextLine();
int store[] = { 6, 6, 6, 6, 6, 6 };
if (input[1].equals("B") || input[1].equals("Book")
|| input[1].equals(
"book") || input[1].equals("b")) {
String temp[][] =
new String[5][4];
int random[] = new int[5];
boolean repeat = true;
int nums[] = new int[5];
for (int i = 0; i < 5; i++) {
temp[i][0] =
"book";
temp[i][1] =
names[i];
temp[i][2] =
lexile[i];
temp[i][3] =
grade[i];
for (int qwop = 0; qwop < 4; qwop++) {
medium[i][qwop] = temp[i][qwop];
if (qwop == 0)
System.
out.printf(i + 1 + " | ");
else if (qwop < 3)
System.
out.printf(medium[i][qwop] + " | ");
else
System.
out.println(medium[i][qwop] + "\n");
Thread.sleep(150);
}
// System.out.println(temp[i][i]);
// random = store[i];
if (i == 4)
System.
out.printf("\n\n\n");
}
}
if (input[1].equals("C") || input[1].equals("c")
|| input[1].equalsIgnoreCase(
"CD") || input[1].equals("cd")) {
String temp[][] =
new String[5][4];
for (int i = 0; i < 5; i++) {
int random1 = (int) (Math.random() * max) + 6;
for (int p = 0; p < 4; p++) {
for (random1 = (int) (Math.random() * max) + 6; random1 == store[p];) {
random1 = (
int) (Math.random() * max) + 6;
}
}
temp[i][0] =
"CD";
temp[i][1] =
names[i + 5];
temp[i][2] =
lexile[i + 5];
temp[i][3] =
grade[i + 5];
for (int qwop = 0; qwop < 4; qwop++) {
medium[i][qwop] = temp[i][qwop];
if (qwop < 3)
System.
out.printf(medium[i][qwop] + " | ");
else
System.
out.println(medium[i][qwop] + "\n");
Thread.sleep(150);
}
// System.out.println(temp[i][i]);
random1 = store[i];
if (i == 4)
System.
out.printf("\n\n\n");
}
}
if (input[1].equalsIgnoreCase("D") || input[1].equalsIgnoreCase("DVD")) {
String temp[][] =
new String[5][4];
for (int i = 0; i < 5; i++) {
int random1 = (int) (Math.random() * max) + 6;
for (int p = 0; p < 4; p++) {
for (random1 = (int) (Math.random() * max) + 6; random1 == store[p];) {
random1 = (
int) (Math.random() * max) + 6;
}
}
temp[i][0] =
"DVD";
temp[i][1] =
names[i + 10];
temp[i][2] =
lexile[i + 10];
temp[i][3] =
grade[i + 10];
for (int qwop = 0; qwop < 4; qwop++) {
medium[i][qwop] = temp[i][qwop];
if (qwop < 3)
System.
out.printf(medium[i][qwop] + " | ");
else
System.
out.println(medium[i][qwop] + "\n");
Thread.sleep(150);
}
// System.out.println(temp[i][i]);
random1 = store[i];
if (i == 4)
System.
out.printf("\n\n\n");
}
}
// for loop goes through each of the parameters and compltes the
// instructions
System.
out
.println(
"How would you like to sort?\nA)Name B) Lexile C) Grade Level");
input[2] = ScanObj.nextLine();
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 2; j++) {
// if statement checks if the condition is true, then does the
// instructions if it is
// compareTo checks the ascii values of two strings. If the
// second
// is smaller (would come first in alphabetic order) it returns
// -1
boolean mismatch = true;
while (mismatch) {
if (input[2].equalsIgnoreCase("a")) {
mismatch =
false;
// makes a new temporary String
String temp1 =
null;
// Switches the String at position i with the one above
// it
for (int z = 0; z < medium.length - 1; z++) {
for (int x = z + 1; x < medium.length; x++) {
if (medium[z][1].compareTo(medium[x][1]) > 0) {
for (int qwop = 0; qwop < 4; qwop++) {
temp1 =
medium[z][qwop];
medium[z][qwop] = medium[x][qwop];
medium[x][qwop] = temp1;
}
mismatch =
true;
}
}
}
}
if (input[2].equalsIgnoreCase("b")) {
mismatch =
false;
// makes a new temporary String
String temp3 =
null;
// Switches the String at position i with the one above
// it
for (int z = 0; z < medium.length - 1; z++) {
for (int x = z + 1; x < medium.length; x++) {
if (medium[z][2].compareTo(medium[x][2]) > 0) {
for (int qwop = 0; qwop < 4; qwop++) {
temp3 =
medium[z][qwop];
medium[z][qwop] = medium[x][qwop];
medium[x][qwop] = temp3;
}
mismatch =
true;
}
}
}
}
if (input[2].equalsIgnoreCase("c")) {
mismatch =
false;
// makes a new temporary String
String temp3 =
null;
// Switches the String at position i with the one above
// it
for (int z = 0; z < medium.length - 1; z++) {
for (int x = z + 1; x < medium.length; x++) {
// Here I encounter an error because compareTo()
// sorts Lexicographically, meaning anything
// starting with a 1 comes before anything
// starting with a 2, 3, etc. This means that
// Grade 11 comes before grade 9, and simply
// comparing greater than does not work due to
// the fact that they are Strings.
if (medium[z][3].compareTo(medium[x][3]) > 0) {
for (int qwop = 0; qwop < 4; qwop++) {
temp3 =
medium[z][qwop];
medium[z][qwop] = medium[x][qwop];
medium[x][qwop] = temp3;
}
mismatch =
true;
}
}
}
}
}
}
}
Thread.sleep(1000);
for (int prt = 0; prt < medium.length; prt++) {
for (int qwop = 0; qwop < 4; qwop++) {
if (qwop < 3)
System.
out.printf(medium[prt][qwop] + " | ");
else
System.
out.println(medium[prt][qwop]);
}
}
Thread.sleep(1800);
for (int t = 0; t < 1000; t++) {
System.
out.println("\n\n\nTo edit a selection, type edit\n"
+
"To sort by a different category, type sort\n"
+
"To browse another medium, type browse\n"
+
"To search the " + medium[1][0] + "s, type search");
input[3] = ScanObj.nextLine();
if (input[3].equalsIgnoreCase("browse")) {
Thread.sleep(500);
System.out.println("What would you like to browse?:");
if (medium[1][0].equals("book")) {
System.out.println("CDs, or DVDs");
input[4] = ScanObj.nextLine();
}
if (medium[1][0].equals("CD")) {
System.out.println("Books, or DVDs");
input[4] = ScanObj.nextLine();
}
if (medium[1][0].equals("DVD")) {
System.out.println("Books, or CDs");
input[4] = ScanObj.nextLine();
}
if (input[4].equalsIgnoreCase("CD")
|| input[4].equalsIgnoreCase("DVD")
|| input[4].equalsIgnoreCase("Book")) {
for (int i = 0; i < 5; i++) {
String temp[][] = new String[5][4];
temp[i][0] =
"CD";
int addon = 0;
if (input[4].equals("CD"))
addon = 5;
if (input[4].equals("DVD"))
addon = 10;
temp[i][1] =
names[i + addon];
temp[i][2] =
lexile[i + addon];
temp[i][3] =
grade[i + addon];
for (int qwop = 0; qwop < 4; qwop++) {
medium[i][qwop] = temp[i][qwop];
if (qwop < 3)
System.
out.printf(medium[i][qwop] + " | ");
else
System.
out.println(medium[i][qwop] + "\n");
Thread.sleep(150);
}
}
}
}
if (input[3].equalsIgnoreCase("edit")) {
Thread.sleep(500);
System.
out.println("First type the number of the " + medium[1][0]
+
"\nyou want to edit");
int input4 = ScanObj.nextInt();
System.
out
.println(
"Now, type the number of the column you want to edit");
int input5 = ScanObj.nextInt();
System.
out.println("Now, make your edit:\n");
input[6] = ScanObj.nextLine();
medium[input4][input5] = input[6];
System.
out.println(medium[input4][input5]);
}
for (int y = 0; y < 10; y++) {
if (input[3].equalsIgnoreCase("search")) {
Thread.sleep(2000);
System.
out.println("Would you like to search by 1) Title or 2) Lexile #");
int input4 = 1;
input4 = ScanObj.nextInt();
Thread.sleep(2500);
System.
out.println("Now Type your search");
input[5] = ScanObj.nextLine();
Thread.sleep(2500);
for (int i = 0; i < 5; i++) {
System.
out.println(input4 + ", " + input[5]);
System.
out.println(medium[i][input4]);
if (input[5].compareToIgnoreCase(medium[i][input4]) == 0) {
y = 10;
System.
out.println("why do you lie");
for (int r = 0; r < 4; r++) {
if (r < 3)
System.
out.printf(medium[i][r] + " | ");
else
System.
out.println(medium[i][r]);
Thread.sleep(150);
}
}
else
System.
out.println(medium[i][input4]);
System.
out.println("Couldn't find item, please search again:");
}
}
}
}
}
}
ScanObj是我的扫描仪。我只是想获得Integer输入，但它总是返回null。怎么了？
答案 0 :(得分：0)
以下是使用扫描仪的示例 -
int choice;
do {
System.out.print("Would you like to search by (1) Title or (2) Lexile # : ");
choice = scan.nextInt();
} while(choice < 1 || choice > 2); // Keep asking the user for a valid integer
如果输入不是整数，则上面的代码会中断。
您可以使用 nextLine -
Scanner scan = new Scanner(System.in);
String response;
do {
System.out.print("Would you like to search by (1) Title or (2) Lexile # : ");
response = scan.nextLine();
} while(!response.equals("1") && !response.equals("2"));
int choice = Integer.parseInt(response);
try {
System.out.print("Say cheeseeeee...");
Thread.sleep(3000);
} catch(InterruptedException e){
// handle exception
e.printStackTrace();
}
System.out.println("\nChoice : " + choice);