Format output using printf and String.Format

Formatted output

In which cases the formatted output is used:

• The use of formatted output in the abnormal print to log is helpful to troubleshoot the cause of the error;

printf format

Example:

  public class PrintfTest {    public static void main(String[] args) {        printfTest1("小明",123456);    }    private static void printfTest1(String name, Integer fansCount) {        System.out.printf("你好,%s,粉丝%d人",name,fansCount);    }  }     

PrintfTest1 () Description:

• %: Characters starting with% will be replaced with corresponding parameters;
• S: Represents a string;
• D: Represents a decimal integer.

Other translator descriptions:

Conversion character	type
D	Decimal integer
X	hexadecimal integer
O	Eight-binary integers
F	Single-precision floating-point number
E	Exponential floating-point number
G	Universal floating point number
A	Hexadecimal floating-point number
S	String
C	Character
B	Boolean
H	Hash code

String.Format formatting

Difference: String.Format does not print output, the other uses the same as printf.
Example:

    // 作为一个变量，可以传入日志info或error中，方便排查bug    String temp = String.format("%1$s ,测试, %2$s","小明","测试");

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