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• JsonUtils.java

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com.penglecode.codeforce.common.util.JsonUtils Maven / Gradle / Ivy

package com.penglecode.codeforce.common.util;

import com.fasterxml.jackson.core.JsonParser.Feature;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.datatype.jdk8.Jdk8Module;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import org.apache.commons.lang3.StringUtils;
import org.springframework.core.NestedRuntimeException;
import org.springframework.core.convert.ConversionService;
import org.springframework.core.convert.support.DefaultConversionService;

import java.io.IOException;
import java.text.SimpleDateFormat;

/**
 * 基于Jackson2的JSON工具类
 *
 * @author pengpeng
 * @version 1.0
 */
public class JsonUtils {

	private static final ConversionService DEFAULT_CONVERSION_SERVICE = new DefaultConversionService();

	public static final String DEFAULT_EMPTY_JSON_OBJECT = "{}";
	
	public static final String DEFAULT_EMPTY_JSON_ARRAY = "[]";
	
	public static final String DEFAULT_DATE_FORMAT = "yyyy-MM-dd HH:mm:ss";
	
	private static final ObjectMapper DEFAULT_OBJECT_MAPPER = createDefaultObjectMapper();

	private JsonUtils() {}

	/**
	 * 对象转json字符串
	 * @param object
	 * @return
	 */
	public static String object2Json(Object object) {
		return object2Json(DEFAULT_OBJECT_MAPPER, object);
	}
	
	/**
	 * 对象转json字符串
	 * @param objectMapper
	 * @param object
	 * @return
	 */
	public static String object2Json(ObjectMapper objectMapper, Object object) {
		try {
			if(object != null) {
				return objectMapper.writeValueAsString(object);
			}
			return null;
		} catch (JsonProcessingException e) {
			throw new JsonAccessException(e.getMessage(), e);
		}
	}
	
	/**
	 * json字符串转普通javabean
	 * @param 
	 * @param json
	 * @param clazz		- 注：clazz所指对象存在泛型,例如 Result 则转换后User的实际类型是个Map,此类情况应该使用TypeReference进行转换
	 * @return
	 */
	public static  T json2Object(String json, Class clazz) {
		return json2Object(DEFAULT_OBJECT_MAPPER, json, clazz);
	}
	
	/**
	 * json字符串转普通javabean
	 * @param 
	 * @param objectMapper
	 * @param json
	 * @param clazz		- 注：clazz所指对象存在泛型,例如 Result 则转换后User的实际类型是个Map,此类情况应该使用TypeReference进行转换
	 * @return
	 */
	public static  T json2Object(ObjectMapper objectMapper, String json, Class clazz) {
		try {
			if(!StringUtils.isEmpty(json)) {
				return objectMapper.readValue(json, clazz);
			}
			return null;
		} catch (Exception e) {
			throw new JsonAccessException(e.getMessage(), e);
		}
	}
	
	/**
	 * json字符串转泛型类对象
	 * 示例： List userList = json2Object("[{"username":"jack","accounts":[{"accountId":"","amount":1200.00},...]},...]", new TypeReference>(){});
	 * 		  Result result = json2Object("{"success": true, "message": "OK", data: {"userId": 12345, "userName": "jack"}}", new TypeReference>(){});
	 * @param 
	 * @param json
	 * @param typeReference
	 * @return
	 */
	public static  T json2Object(String json, TypeReference typeReference) {
		return json2Object(DEFAULT_OBJECT_MAPPER, json, typeReference);
	}

	/**
	 * json字符串转泛型类对象
	 * @param json
	 * @param converter
	 * @param 
	 * @return
	 */
	public static  T json2Object(String json, Json2ObjectConverter converter) {
		try {
			if(!StringUtils.isEmpty(json)) {
				return converter.convert(DEFAULT_OBJECT_MAPPER, DEFAULT_OBJECT_MAPPER.readTree(json));
			}
		} catch (Exception e) {
			throw new JsonAccessException(e.getMessage(), e);
		}
		return null;
	}
	
	/**
	 * json字符串转泛型类对象
	 * 示例： List userList = json2Object("[{"username":"jack","accounts":[{"accountId":"","amount":1200.00},...]},...]", new TypeReference>(){});
	 * 		  Result result = json2Object("{"success": true, "message": "OK", data: {"userId": 12345, "userName": "jack"}}", new TypeReference>(){});
	 * @param 
	 * @param objectMapper
	 * @param json
	 * @param typeReference
	 * @return
	 */
	public static  T json2Object(ObjectMapper objectMapper, String json, TypeReference typeReference) {
		try {
			if(!StringUtils.isEmpty(json)) {
				return objectMapper.readValue(json, typeReference);
			}
			return null;
		} catch (Exception e) {
			throw new JsonAccessException(e.getMessage(), e);
		}
	}
	
	/**
	 * 创建根JsonNode
	 * @param json
	 * @return
	 */
	public static JsonNode createRootJsonNode(String json) {
		return createRootJsonNode(DEFAULT_OBJECT_MAPPER, json);
	}
	
	/**
	 * 创建根JsonNode
	 * @param objectMapper
	 * @param json
	 * @return
	 */
	public static JsonNode createRootJsonNode(ObjectMapper objectMapper, String json) {
		try {
			return objectMapper.readTree(json);
		} catch (IOException e) {
			throw new JsonAccessException(e.getMessage(), e);
		}
	}
	
	/**
	 * 判断json字符串是否是JSON对象
	 * @param json
	 * @return
	 */
	public static boolean isJsonObject(String json) {
		if(json != null) {
			return json.startsWith("{") && json.endsWith("}");
		}
		return false;
	}
	
	/**
	 * 判断json字符串是否是JSON数组
	 * @param json
	 * @return
	 */
	public static boolean isJsonArray(String json) {
		if(json != null) {
			return json.startsWith("[") && json.endsWith("]");
		}
		return false;
	}
	
	/**
	 * 判断json字符串是否是JSON Object数组
	 * @param json
	 * @return
	 */
	public static boolean isJsonObjectArray(String json) {
		boolean b = isJsonArray(json);
		if(b) {
			json = StringUtils.trim(StringUtils.strip(json, "[]"));
			return json.startsWith("{") && json.endsWith("}");
		}
		return false;
	}

	public static String toString(JsonNode parentNode, String fieldName) {
		JsonNode jsonNode = parentNode.get(fieldName);
		if(jsonNode != null) {
			return jsonNode.toString();
		}
		return null;
	}

	public static String getString(JsonNode parentNode, String fieldName) {
		return getString(parentNode, fieldName, null);
	}

	public static String getString(JsonNode parentNode, String fieldName, String defaultValue) {
		JsonNode jsonNode = parentNode.get(fieldName);
		if(jsonNode != null) {
			return StringUtils.defaultIfEmpty(jsonNode.asText(), defaultValue);
		}
		return null;
	}

	public static Boolean getBoolean(JsonNode parentNode, String fieldName) {
		return getBoolean(parentNode, fieldName, null);
	}

	public static Boolean getBoolean(JsonNode parentNode, String fieldName, Boolean defaultValue) {
		String fieldValue = getString(parentNode, fieldName, null);
		if(fieldValue != null) {
			return DEFAULT_CONVERSION_SERVICE.convert(fieldValue, Boolean.class);
		}
		return defaultValue;
	}

	public static Byte getByte(JsonNode parentNode, String fieldName) {
		return getByte(parentNode, fieldName, null);
	}

	public static Byte getByte(JsonNode parentNode, String fieldName, Byte defaultValue) {
		String fieldValue = getString(parentNode, fieldName, defaultValue != null ? defaultValue.toString() : null);
		if(fieldValue != null) {
			return DEFAULT_CONVERSION_SERVICE.convert(fieldValue, Byte.class);
		}
		return null;
	}

	public static Short getShort(JsonNode parentNode, String fieldName) {
		return getShort(parentNode, fieldName, null);
	}

	public static Short getShort(JsonNode parentNode, String fieldName, Short defaultValue) {
		String fieldValue = getString(parentNode, fieldName, defaultValue != null ? defaultValue.toString() : null);
		if(fieldValue != null) {
			return DEFAULT_CONVERSION_SERVICE.convert(fieldValue, Short.class);
		}
		return null;
	}

	public static Integer getInteger(JsonNode parentNode, String fieldName) {
		return getInteger(parentNode, fieldName, null);
	}

	public static Integer getInteger(JsonNode parentNode, String fieldName, Integer defaultValue) {
		String fieldValue = getString(parentNode, fieldName, defaultValue != null ? defaultValue.toString() : null);
		if(fieldValue != null) {
			return DEFAULT_CONVERSION_SERVICE.convert(fieldValue, Integer.class);
		}
		return null;
	}

	public static Float getFloat(JsonNode parentNode, String fieldName) {
		return getFloat(parentNode, fieldName, null);
	}

	public static Float getFloat(JsonNode parentNode, String fieldName, Float defaultValue) {
		String fieldValue = getString(parentNode, fieldName, defaultValue != null ? defaultValue.toString() : null);
		if(fieldValue != null) {
			return DEFAULT_CONVERSION_SERVICE.convert(fieldValue, Float.class);
		}
		return null;
	}

	public static Double getDouble(JsonNode parentNode, String fieldName) {
		return getDouble(parentNode, fieldName, null);
	}

	public static Double getDouble(JsonNode parentNode, String fieldName, Double defaultValue) {
		String fieldValue = getString(parentNode, fieldName, defaultValue != null ? defaultValue.toString() : null);
		if(fieldValue != null) {
			return DEFAULT_CONVERSION_SERVICE.convert(fieldValue, Double.class);
		}
		return null;
	}

	public static Long getLong(JsonNode parentNode, String fieldName) {
		return getLong(parentNode, fieldName, null);
	}

	public static Long getLong(JsonNode parentNode, String fieldName, Long defaultValue) {
		String fieldValue = getString(parentNode, fieldName, defaultValue != null ? defaultValue.toString() : null);
		if(fieldValue != null) {
			return DEFAULT_CONVERSION_SERVICE.convert(fieldValue, Long.class);
		}
		return null;
	}
	
	/**
	 * 创建默认配置的ObjectMapper
	 * @return
	 */
	public static ObjectMapper createDefaultObjectMapper() {
		ObjectMapper objectMapper = new ObjectMapper();
		//去掉默认的时间戳格式
		objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
		//设置输入时忽略在JSON字符串中存在但Java对象实际没有的属性
		objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
		objectMapper.setDateFormat(new SimpleDateFormat(DEFAULT_DATE_FORMAT));
		objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
		//单引号处理,允许单引号
		objectMapper.configure(Feature.ALLOW_SINGLE_QUOTES, true);
		objectMapper.configure(Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);

		objectMapper.registerModule(new Jdk8Module());
		objectMapper.registerModule(new JavaTimeModule());
		return objectMapper;
	}
	
	public static ObjectMapper getDefaultObjectMapper() {
		return DEFAULT_OBJECT_MAPPER;
	}

	@FunctionalInterface
	public interface Json2ObjectConverter {

		T convert(ObjectMapper objectMapper, JsonNode rootNode) throws Exception;

	}

	public static class JsonAccessException extends NestedRuntimeException {

		private static final long serialVersionUID = 1L;

		public JsonAccessException(String message, Throwable cause) {
			super(message, cause);
		}

	}
	
}