Convert list to string object

First write a tool class JsonUtils.java, and then adjust the class conversion

         //Convert list to string
	String cacheString = JsonUtils.objectToJson(list);

JsonUtils.java tool class

public class JsonUtils {

    // define the jackson object
    private static final ObjectMapper MAPPER = new ObjectMapper();

    /**
     * Convert the object to a json string.
     * <p>Title: pojoToJson</p>
     * <p>Description: </p>
     * @param data
     * @return
     */
    public static String objectToJson(Object data) {
    	try {
			String string = MAPPER.writeValueAsString(data);
			return string;
		} catch (JsonProcessingException e) {
			e.printStackTrace ();
		}
    	return null;
    }
    
    /**
     * Convert json result set to object
     *
     * @param jsonData json data
     * @param clazz object type in the object
     * @return
     */
    public static <T> T jsonToPojo(String jsonData, Class<T> beanType) {
        try {
            T t = MAPPER.readValue(jsonData, beanType);
            return t;
        } catch (Exception e) {
        	e.printStackTrace ();
        }
        return null;
    }
    
    /**
     * Convert json data to pojo object list
     * <p>Title: jsonToList</p>
     * <p>Description: </p>
     * @param jsonData
     * @param beanType
     * @return
     */
    public static <T>List<T> jsonToList(String jsonData, Class<T> beanType) {
    	JavaType javaType = MAPPER.getTypeFactory().constructParametricType(List.class, beanType);
    	try {
    		List<T> list = MAPPER.readValue(jsonData, javaType);
    		return list;
		} catch (Exception e) {
			e.printStackTrace ();
		}
    	
    	return null;
    }
    
}