CODEWITHSUNDEEP
javaspringjunit
dev
dev

Reputation: 451

How to convert object to query string in Java?

I am trying to convert the following object to query string, so that can be used with GET request.

Class A {
  String prop1;
  String prop2;
  Date date1;
  Date date2;
  ClassB objB;
}

Class B {
 String prop3;
 String prop4;
}

We can do that first object to Map then convert map to MultiValueMap and use URIComponentsBuilder.fromHttpUrl("httpL//example.com").queryParams(multiValueMap).build();

Is there shorter and better way of converting object to query string so that be used with GET request in Spring Project for Junit Test?

Upvotes: 8

Views: 16322

Answers (4)

silentsudo
silentsudo

Reputation: 6963

This is how i would do it,

Create Map, populate and then iterate over map items and append to builder this seems to be working for me. It does not cover support for nested objects. Should be simple with recursion.

public String getRequestString(Class clazz, Object o) {
        StringBuilder queryStringBuilder = new StringBuilder();
        final Map<String, String> queryParams = new LinkedHashMap<>();

        try {
            for (Field f : clazz.getDeclaredFields()) {
                f.setAccessible(true);
                queryParams.put(f.getName(), String.valueOf(f.get(o)));
            }
            for (Map.Entry<String, String> entry : queryParams.entrySet()) {
                queryStringBuilder.append(testStringUtils.toSnakeCase(entry.getKey()));
                queryStringBuilder.append("=");
                queryStringBuilder.append(entry.getValue());
                queryStringBuilder.append("&");
            }
            logger.info("Map: " + queryParams);
        } catch (Exception e) {
            e.printStackTrace();
        }
        final String queryString = queryStringBuilder.toString();
        logger.info("Query string : " + queryString.substring(0, queryString.length() - 1));
        return "?" + queryString.substring(0, queryString.length() - 1);

Upvotes: 0

shark1608
shark1608

Reputation: 719

You could write your own method that uses java.lang.reflect. Here's an example

public static String getRequestString(String urlString, Class clazz, Object o){
    String queryString = "?";

    try {
        for (Field f : clazz.getDeclaredFields()) {
            f.setAccessible(true);
            queryString += queryString.concat(f.getName() + "=" + String.valueOf(f.get(o)) + "&");
        }
    }catch (Exception e){
        e.printStackTrace();
    }

    return urlString + queryString.substring(0,queryString.length()-1);
}

Upvotes: 3

fabiojb
fabiojb

Reputation: 331

OpenFeign has the annotation @QueryMap to generate query params dinamicaly based on a object attributes:

public interface Api {
  @RequestLine("GET /find")
  V find(@QueryMap CustomPojo customPojo);
}

See more at: https://github.com/OpenFeign/feign#dynamic-query-parameters

Upvotes: 1

Andreas
Andreas

Reputation: 159086

Why convert to Map then MultiValueMap, instead of just building it directly?

DateFormat dateFmt = new SimpleDateFormat("whatever date format you want");
URIComponentsBuilder.fromHttpUrl("httpL//example.com")
                    .queryParam("prop1", a.prop1)
                    .queryParam("prop2", a.prop2)
                    .queryParam("date1", dateFmt.format(a.date1))
                    .queryParam("date2", dateFmt.format(a.date2))
                    .queryParam("prop3", a.objB.prop3)
                    .queryParam("prop4", a.objB.prop4)
                    .build();

Upvotes: 3

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