简化Java中复杂的if语句

Question

Is there a way to simplyfy the below code, I can combine condition1 and condition2 but I want the else statements print different messages for each step.

if(condition1){
    if(condition2){
        if(condition3){
            //do something
        }
    }
    else{
       //sout condition2 failed
    }
}
else{
    //sout condition1 failed
}

Answer 1

the simplest i could come up with is

if(condition1 && condition2 && condition3){
    //do something
}
else if(!condition1){
    //sout condition1 failed
}
else if(!condition2){
    //sout condition2 failed
}

Answer 2

The simplest is to flip conditions 1 and 2, so it becomes an if-elseif construct, which doesn't require deeply nested blocks:

if (! condition1) {
    //sout condition1 failed
} else if (! condition2) {
    //sout condition2 failed
} else if (condition3) {
    //do something
}

If you also wanted else block for condition3 (missing in question code), flip condition 3 too.

if (! condition1) {
    //sout condition1 failed
} else if (! condition2) {
    //sout condition2 failed
} else if (! condition3) {
    //sout condition3 failed
} else {
    //do something
}

Answer 3

merge condition 2 and 3

if(condition1){
    if(condition2 && condition3){
       //do something
    }
    else if (!condition2){
       //sout condition2 failed
    }
}
else {
    //sout condition1 failed
}

You can also check the false condition first like

if(!condition1){

    //sout condition1 failed

} else if(!condition2){

    //sout condition2 failed

} else if(condition3){
  //do something
}

Answer 4

if(condition1 && condition2 && condition3){
    //do something
 }

 String failed = !condition1? "condition1 failed":
                 !condition2? "condition2 failed" : "";

 System.out.println(failed);