如何在 Java 中包含和比较字符串和数组

Question

I'm using array and for loop in condition if to compare 'searchedValue' and arrayParameter.

this is my code:

String[] arrayParameter = new String[] {
            "math",
            "physical",
            "literary"
};

boolean found = false;

String searchedValue = "math";
String searchedValue1 = "physical";
String searchedValue2 = "literary";

for(int i=0 ; i< arrayParameter.length; i++) {

    if(arrayParameter[i].equals(searchedValue)) {
        found = true;
        break;
    }
    else if(arrayParameter[i].equals(searchedValue1)) {

        found = true;
        break;
    }
    else if(arrayParameter[i].equals(searchedValue2)) {
        found = true;
        break;
    }
}

HttpEntity<String> entity = new HttpEntity<String>(arrayParameter[i],headers);
String result = restTemplate.postForObject(url, entity, String.class);

logger.debug(result);

When i run my code it cannot compare and return correct result. How to compare/contains 'searchedValue' with 'arrayParameter[i]' and when string found program will stop and continue to outside of method?

Answer 1

• You are using 'i' outside for loop, which is out of its scope.
• Your write too many if-else statements

boolean found = false;
String foundValue = null;

String searchedValue = "math";
String searchedValue1 = "physical";
String searchedValue2 = "literary";

for(int i=0 ; i< arrayParameter.length; i++) {

if(arrayParameter[i].contains(searchedValue) ||  arrayParameter[i].contains(searchedValue1) || arrayParameter[i].contains(searchedValue2)) {
    found = true;
    foundValue = arrayParameter[i];
    break;
}

}
HttpEntity<String> entity = new HttpEntity<String>(foundValue,headers);
String result = restTemplate.postForObject(url, entity, String.class);

logger.debug(result);

Suggestion:

You can use HashSet instead of String[] array. It will reduce your searching time.

O(1) search:

HashSet<String> setParameter = new HashSet<String>(); 

setParameter.add("math");
setParameter.add("physical");
setParameter.add("literary"); 

if(setParameter.contains(searchedValue) ||  setParameter.contains(searchedValue1) || setParameter.contains(searchedValue2)) {
    found = true;
    foundValue = arrayParameter[i];
    break;
}

Answer 2

I think you can easily use Arrays.asList(arrayParameter).contains(searchedValue) to create your intented approach. With this you can eliminate the loop. Note that if you used exact below approach, your API won't called if there is no match. But above you example API call goes even there is no matches, with null for foundValue.

if (Arrays.asList(arrayParameter).contains(searchedValue)){
    callApi(searchedValue)
}
if (Arrays.asList(arrayParameter).contains(searchedValue1)){
    callApi(searchedValue1)
}
if (Arrays.asList(arrayParameter).contains(searchedValue2)){
    callApi(searchedValue2)
}

private void callApi(String foundValue){
   
    HttpEntity<String> entity = new HttpEntity<String>(foundValue,headers);
    String result = restTemplate.postForObject(url, entity, String.class);
    logger.debug(result);
}