Java中的字符串格式，单词的最大宽度和右括号

Question

I want to get the below format

abc 12 [hello-wo]       this is message1
abc 12 [hello-world]    this is message2
abc 10 [hello-wor]      this is message2  

I tried using

String format1 = "%s %d [%s-%s] %s\n";
String format2 = "%s %d [%s-%-20s] %s\n";
    String a = String.format(format1,"abc","12",hello,"wo","this is message1");
    System.out.print(a);

I resulted like below by using two formats (format1 and format2)

format1

abc 12 [hello-wda] this is message1
abc 12 [hello-world] this is message2
abc 10 [hello-wor] this is message2

format2

abc 12 [hello-wo                  ] this is message1
abc 12 [hello-world               ] this is message2
abc 12 [hello-wor                 ] this is message1

What I want is to align the last part of the parameter in same vertical position and closing square brackets should be at the end of the 4th parameter without any spaces.

Answer 1

What you describe is transforming the argument. This is not what formatters generally do (unless with numbers and dates, ie pretty specific stuff).

There is no way you can do what you want, I think, but you can work around it by using pattern and converting your args manually, like this:

The pattern:

String PATTERN = "%s %d [%s-%-21s %s\n"; // notice that I've removed the closing bracket.
                                         // See below

Applying the arguments:

String arg = "world";
arg = arg.trim();
arg = arg.substring(0, Math.min(arg.length(), 20));
String.format(PATTERN, "abc", "12", "hello",
    /*Attention here: changing next argument by appending close bracket */
    arg + "]",
    "this is the message");

Answer 2

Here a trick how you can solve your problem :

public void formatString(String hello) {
    String format1 = "%s %s %s\n";
    String firstPart = String.format("%s %d [%s-%s]", "abc", 12, hello, "wo");
    String a = String.format(
            format1, firstPart, 
            String.format("%0" + Math.abs(30 - firstPart.length()) + "d", 0).replace("0", " "), 
            "this is message1");
    System.out.print(a);
}

Test case :

formatString("hello-wda");
formatString("hello-world");
formatString("hello-wor");

Outputs

abc 12 [hello-wda-wo]           this is message1
abc 12 [hello-world-wo]         this is message1
abc 12 [hello-wor-wo]           this is message1

---

The trick is to use two format, the first one to create the first part, we need this part to calculate the number of space needs to be equilibrium, the second format to combine the first part + the spaces between the first and second part + second part.

I used 30 as default value you can change it with your needs.