int2String

int i = 9;
String j = i+””;
String j = String.valueOf(i);
String str_j  =  Double.toString(i);

String2int

int dot = Integer.valueOf(str);

String2double

double dot = Double.parseDouble(str);
double dot = Double.valueOf(str);

String 转 String数组

String Str = "您好/你们好/早上好/下午好";
String[]  ss = wordString.split("/");

数组 Array转String

double[] arr = {1,2,3,4};// float[]  int[]  如是。
String str = Arrays.toString(arr);

动态数组与静态数组

静态数组：Double[] douArray = new Double[20];
动态数组：
Double[] douArray;
douArray = new Double[**.length];