1. 변경 전 (한글 깨질 때)

URL url = new URL(address);
HttpURLConnection uc = (HttpURLConnection) url.openConnection();
uc.setConnectTimeout(timeout);
InputStreamReader in = new InputStreamReader((InputStream)uc.getContent());

2. 변경 후 (한글, 한자 안깨짐)

URL url = new URL(address);
HttpURLConnection uc = (HttpURLConnection) url.openConnection();
uc.setConnectTimeout(timeout);
InputStreamReader in = new InputStreamReader((InputStream)uc.getContent(), "UTF-8");

3. Springboot에서 한글 깨짐 해결 방법

하지만 본인은 해결되지 않음.

application.properties 에 다음 추가

# Charset of HTTP requests and responses. Added to the "Content-Type" header if not set explicitly.
spring.http.encoding.charset=UTF-8
# Enable http encoding support.
spring.http.encoding.enabled=true
# Force the encoding to the configured charset on HTTP requests and responses.
spring.http.encoding.force=true