"= =" difference from equals

      equals It is mainly applied to reference type strings （String） Comparison of contents ,"==" Compare memory addresses , Therefore, inaccurate results will be produced during comparison （ As shown in Fig. 1 ）.

notes ： When comparing pure character strings , If case insensitive comparison , You can call equalsIgnoreCase();

               "==" It belongs to the relational operator , Can be used to compare some （ except double） Basic data type , Such as ：int char Whether the data or calculation results of are equal （ Pictured ）

          attach ：double Type cannot be used "==" Compare , The result will produce errors , some double The calculation result of type is not accurate , So compare double type , Usually we will judge whether the absolute value of their difference is less than a specific value ; Refer to the below