type converter : formatter

typeconverter/src/main/java/hello/typeconverter/fomatter/MyNumberFormatter.java

@@ -0,0 +1,26 @@
+package hello.typeconverter.fomatter;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.format.Formatter;
+
+import java.text.NumberFormat;
+import java.text.ParseException;
+import java.util.Locale;
+
+@Slf4j
+public class MyNumberFormatter implements Formatter<Number> {
+
+    @Override
+    public Number parse(String text, Locale locale) throws ParseException {
+        log.info("text={}, locale={}", text, locale);
+        // "1,000" -> 1000
+        NumberFormat format = NumberFormat.getInstance(locale);
+        return format.parse(text);
+    }
+
+    @Override
+    public String print(Number object, Locale locale) {
+        log.info("object={}, locale={}", object, locale);
+        return NumberFormat.getInstance(locale).format(object);
+    }
+}

typeconverter/src/test/java/hello/typeconverter/fomatter/MyNumberFormatterTest.java

@@ -0,0 +1,27 @@
+package hello.typeconverter.fomatter;
+
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.text.ParseException;
+import java.util.Locale;
+
+import static org.assertj.core.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.*;
+
+class MyNumberFormatterTest {
+
+    MyNumberFormatter formatter = new MyNumberFormatter();
+
+    @Test
+    void parse() throws ParseException {
+        Number result = formatter.parse("1,000", Locale.KOREA);
+        assertThat(result).isEqualTo(1000L);
+    }
+
+    @Test
+    void print() {
+        String result = formatter.print(1000, Locale.KOREA);
+        assertThat(result).isEqualTo("1,000");
+    }
+}