Java使用ObjectMapper做数据转换的常用工具类实现
superSubfn 人气:11.介绍
ObjectMapper类是Jackson库的主要类,它提供一些功能将数据集或对象转换的实现
2.依赖包
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind --> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.9.5</version> <https://img.qb5200.com/download-x/dependency> <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core --> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-core</artifactId> <version>2.9.5</version> <https://img.qb5200.com/download-x/dependency> <!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-annotations --> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-annotations</artifactId> <version>2.9.5</version> <https://img.qb5200.com/download-x/dependency>
3.工具类实现
package org.tempuri; import java.io.IOException; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import com.fasterxml.jackson.annotation.JsonInclude.Include; import com.fasterxml.jackson.core.JsonParseException; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.DeserializationFeature; import com.fasterxml.jackson.databind.JsonMappingException; import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.SerializationFeature; public class JsonUtils { private static ObjectMapper mapper = new ObjectMapper(); static { //序列化的时候序列对象的所有属性 mapper.setSerializationInclusion(Include.ALWAYS); //反序列化的时候如果多了其他属性,不抛出异常 mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false); //如果是空对象的时候,不抛异常 mapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false); //取消时间的转化格式,默认是时间戳,可以取消,同时需要设置要表现的时间格式 mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false); mapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")); } /** * 对象转为Json字符串 * @param data * @return */ public static String transferToJson(Object data) { String jsonStr = null; try { jsonStr = mapper.writeValueAsString(data); } catch (JsonProcessingException e) { e.printStackTrace(); } return jsonStr; } /** * 对象转为byte数组 * @param data * @return */ public static byte[] transferToBytes(Object data) { byte[] byteArr = null; try { byteArr = mapper.writeValueAsBytes(data); } catch (JsonProcessingException e) { e.printStackTrace(); } return byteArr; } /** * json字符串转为对象 * @param str * @param valueType * @return */ public static <T> T jsonToTransfer(String str, Class<T> valueType) { T data = null; try { data = mapper.readValue(str, valueType); } catch (JsonParseException e) { e.printStackTrace(); } catch (JsonMappingException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return data; } /** * byte数组转为对象 * @param byteArr * @param valueType * @return */ public static <T> T bytesToTransfer(byte[] byteArr, Class<T> valueType) { T data = null; try { data = mapper.readValue(byteArr, valueType); } catch (JsonParseException e) { e.printStackTrace(); } catch (JsonMappingException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return data; } public static void main(String[] args) { List<Map<String, String>> list = new ArrayList<>(); Map<String, String> map1 = new HashMap<>(); map1.put("id", "1"); map1.put("name", "我是一"); list.add(map1); Map<String, String> map3 = new HashMap<>(); map3.put("id", "3"); map3.put("name", "我是三"); list.add(map3); Map<String, String> map2 = new HashMap<>(); map2.put("id", "2"); map2.put("name", "我是二"); list.add(map2); System.out.println(list); System.out.println(transferToJson(list)); } }
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