//The first method is the simplest.

str = I+" "；

system . out . println(" str = "+str ")；

//The second method

Integer it = new integer (i);

str = it . tostring()；

system . out . println(" str = "+str ")；

//The third method

str = integer . tostring(I)；

system . out . println(" str = "+str ")；

//The fourth method

str = string . value of(I)；

system . out . println(" str = "+str ")；

Integer usage

Data type conversion

1) Integer type to character type: (Int type cannot be directly converted into character type, and must be modified into intrger type before conversion).

For example: int a =123;

The first method:? string b = integer . tostring(a)；

It means to change a into an integer first, and then convert it into a character type.

The second method: string b = string.valueof (a);

Directly use the method in String to directly convert. String.valueOf () can be applied to any data type without exception.

2 From character type to integer type: string c = "123";

Method1:int d = integer.valueof (c);

Method 2: int d = integer.parseint (c);

To convert a string into a basic data type (int), it is required that the string must be in a number format.

Function: splicing of strings;

" 123"+"456"= 123456;

But an integer is the addition of two numbers;

At first, I didn't understand the difference between his 1234 and the types of numbers and characters, and then I gradually understood it when I applied it.