use junit test to replace main() for testing

xxl-job-admin/src/main/java/com/xxl/job/admin/core/util/JacksonUtil.java

 import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
-import java.util.HashMap;
-import java.util.Map;
 
 /**
  * Jackson util
 		}
 		return null;
 	}
-
-    /*public static <T> T readValueRefer(String jsonStr, Class<T> clazz) {
-    	try {
-			return getInstance().readValue(jsonStr, new TypeReference<T>() { });
-		} catch (JsonParseException e) {
-			logger.error(e.getMessage(), e);
-		} catch (JsonMappingException e) {
-			logger.error(e.getMessage(), e);
-		} catch (IOException e) {
-			logger.error(e.getMessage(), e);
-		}
-    	return null;
-    }*/
-
-    public static void main(String[] args) {
-		try {
-			Map<String, String> map = new HashMap<String, String>();
-			map.put("aaa", "111");
-			map.put("bbb", "222");
-			String json = writeValueAsString(map);
-			System.out.println(json);
-			System.out.println(readValue(json, Map.class));
-		} catch (Exception e) {
-			logger.error(e.getMessage(), e);
-		}
-	}
 }

xxl-job-admin/src/test/java/com/xxl/job/admin/core/util/JacksonUtilTest.java

+package com.xxl.job.admin.core.util;
+
+import org.hamcrest.core.Is;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static com.xxl.job.admin.core.util.JacksonUtil.writeValueAsString;
+import static org.hamcrest.core.Is.is;
+import static org.junit.Assert.assertThat;
+
+public class JacksonUtilTest {
+
+    @Test
+    public void shouldWriteValueAsString() {
+        //given
+        Map<String, String> map = new HashMap<>();
+        map.put("aaa", "111");
+        map.put("bbb", "222");
+
+        //when
+        String json = writeValueAsString(map);
+
+        //then
+        assertThat(json, is("{\"aaa\":\"111\",\"bbb\":\"222\"}"));
+    }
+
+    @Test
+    public void shouldReadValueAsObject() {
+        //given
+        String jsonString = "{\"aaa\":\"111\",\"bbb\":\"222\"}";
+
+        //when
+        Map result = JacksonUtil.readValue(jsonString, Map.class);
+
+        //then
+        assertThat(result.get("aaa"), Is.<Object>is("111"));
+        assertThat(result.get("bbb"), Is.<Object>is("222"));
+
+    }
+}