How to replace named parameter in a string

Question

I am working on a project built on Java. I have a use case where I have multiple templates of strings that need to be formatted by replacing keywords with their values.

Since the position of parameter and name of the parameter is not always known and will change over time I want to write a function that takes a string and replace keywords (named parameter) with their values using the map.

For e.g.

Hi my name is %name

And if I have map = {"name":"user1"}

Then my function should replace the name with user1.

I tried to find if there is already an existing method or library in java but I couldn't find any.

Does this answer your question? [Java generating Strings with placeholders](https://stackoverflow.com/questions/17364632/java-generating-strings-with-placeholders) — mahbuhs_redoc, Feb 20 '21 at 12:30

score 0 · Answer 1 · answered Feb 20 '21 at 12:28

0

I think you need that:

String name = "Chack";//you will get its field from your map = {"name":"user1"}
String.format("Hi my name is %s", name);

answered Feb 20 '21 at 12:28

Dmitrii B

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Sergey Afinogenov · Answer 2 · 2021-02-20T13:44:24.740

Maybe you need something like that (using a map and replacing all occurrences of keys starting with %):

Map<String, String> map= new HashMap();
map.put("name1", "user1");
map.put("name2", "user2");

String str = "Hi my name is %name1. Hi my name is %name2 and %name1";

String result = map.keySet()
                   .stream()
                   .reduce(str, (s, e) -> s.replaceAll("%"+e+"\\b", map.get(e)));
    
System.out.println(result);

score 0 · Answer 3 · answered Feb 20 '21 at 13:05

U can use simply String.format:

String name = "Example"
String.format("Hi my name is %s", name);

Or message format:

String exampleTemplate = "Hi my name is {0}";
String name = "Example Name"
String message = MessageFormat.format(exampleTemplate, name);

How to replace named parameter in a string

3 Answers3