JAVA中整型数组、字符串数组、整型数和字符串 的创建与转换的方法

char a[]={'A','b','c','E'};
String str1=new String(a);
System.out.println(str1);

String str2;
str2="this is a book";
System.out.println(str2);

char a3[]={'a','b','c','D','6','p'};
String str3=new String(a3,2,4);
System.out.println(str3);

String str4=new String("this is a book");
System.out.println(str4);

int[] arr = {1,2,4, …};

int[] arr;
arr = new int[]{1,2,3, …};

int[] arr1= new int[3];

  String str="123456";
  char[] c = str.toCharArray() ;
  System.out.println(c);

  String str="123456";
  int[] a = new int[str.length()];
  for(int i=0;i<str.length();i++) {
      a[i]  = str.charAt(i)-'0';
    }

1、int i = Integer.valueOf(str).intValue();
2、double b = Double.parseDouble(str); 将字符串转换为double型
3、int b = Integer.parseInt(str);   将字符串转换为int型

char[] c = {'a','s','d','4','5',};
String str = new String(c);
System.out.println(str);

char[] c = { '1', '2', '3', '4', '5', };
int[] a = new int[c.length];
   for (int i = 0; i < 5; i++) {
       a[i] = c[i] - '0';
       System.out.println(a[i]);
   }

1、String str = Integer.toString(i);  将整数型转换为字符型
2、String s = String.valueOf(i);  这个可以将double类型转换为字符型
3、String s = "" + i;

import java.util.*;
public class Solution {
    public int FirstNotRepeatingChar(String str) {
        for(int i = 0;i<str.length();i++){
            if(str.indexOf(str.charAt(i))==i && str.indexOf(str.charAt(i),i+1)==-1) return i;
        }
        return -1;
       }
}