How to check If a multiline String contains another multiline String in Java?

Question

1.I tried to use the contains function BUT it did not work, it only works when b = "30-10-1960\n" or b = "Posephine Esmerelda Bloggs\n". How to check if a contains b? 2.Here is the code I wrote.

String a = "name Posephine Esmerelda Bloggs\n" + 
        "birthday 30-10-1960\n" + 
        "address 102 Smith St, Summer hill, NSW 2130\n" + 
        "";
String b = "Posephine Esmerelda Bloggs\n" + 
        "30-10-1960\n";
System.out.println("a.contains(b)");

Answer 1

it works try this -

String a = "name Posephine Esmerelda Bloggs\n" + 
            "birthday 30-10-1960\n" + 
            "address 102 Smith St, Summer hill, NSW 2130\n" + 
            "";
    String b = "Posephine Esmerelda Bloggs\n" + 
            "birthday 30-10-1960\n";
    System.out.println(a.contains(b));

in your code there is some issue - 1. you used as a string literals in println method, it must be a reference. 2. what you are comparing is not same. In 'a' there is extra word 'birthday' that is missing in 'b'.

The correct string sequence i pasted in sample code.

Answer 2

I think the logic you want here is to assert that every line of the b string appears somewhere in the a string:

String a = "name Posephine Esmerelda Bloggs\n" + 
    "birthday 30-10-1960\n" + 
    "address 102 Smith St, Summer hill, NSW 2130\n" + 
    "";
String b = "Posephine Esmerelda Bloggs\n" + 
    "30-10-1960\n";
String[] lines = b.split("\n");

// now check each line
boolean all = true;
for (String line : lines) {
    if (!a.contains(line)) {
        all = false;
        break;
    }
}

if (all) {
    System.out.println("MATCH");
}
else {
    System.out.println("NO MATCH");
}

This prints:

MATCH

Answer 3

for the answer of the question how to find the two parts in b

String[] arr = b.split( "\n" );
int pos = a.indexOf( arr[0] + '\n' );
if( pos > -1 && a.indexOf( arr[1] + '\n', pos ) > -1 )
  System.err.println( "found" );

+ '\n' : finds the parts only if they end with a \n
if the check for the ending '\n' is unnecessary remove both + '\n'
if the parts may be unordered the pos argument can be omitted

without checking for the \n at the end or the order as in the chosen solution

String[] arr = b.split( "\n" );
if( a.indexOf( arr[0] ) > -1 && a.indexOf( arr[1] ) > -1 )
  System.err.println( "found" ); 

the solution without checking is identical to the following

 if( a.contains( arr[0] ) && a.contains( arr[1] ) )
   System.err.println( "found" );

…because contains(s) returns indexOf(s.toString()) > -1