Testing Form posts through MockMVC

If you have Apache HTTPComponents HttpClient on your classpath, you can do it like this:

    mockMvc.perform(post("/some/super/secret/url")
            .contentType(MediaType.APPLICATION_FORM_URLENCODED)
            .content(EntityUtils.toString(new UrlEncodedFormEntity(Arrays.asList(
                    new BasicNameValuePair("someparam1", "true"),
                    new BasicNameValuePair("someparam2", "test")
            )))));

If you don’t have HttpClient, you can do it with a simple helper method that constructs the urlencoded form entity:

    mockMvc.perform(post("/some/super/secret/url")
            .contentType(MediaType.APPLICATION_FORM_URLENCODED)
            .content(buildUrlEncodedFormEntity(
         "someparam1", "value1", 
         "someparam2", "value2"
    ))));

With this helper function:

private String buildUrlEncodedFormEntity(String... params) {
    if( (params.length % 2) > 0 ) {
       throw new IllegalArgumentException("Need to give an even number of parameters");
    }
    StringBuilder result = new StringBuilder();
    for (int i=0; i<params.length; i+=2) {
        if( i > 0 ) {
            result.append('&');
        }
        try {
            result.
            append(URLEncoder.encode(params[i], StandardCharsets.UTF_8.name())).
            append('=').
            append(URLEncoder.encode(params[i+1], StandardCharsets.UTF_8.name()));
        }
        catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        }
    }
    return result.toString();
 }