工作中,接口與接口交互時,常常會將json和bean/list相互轉化,來處理。本文基於jackson來封裝工具
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1.說明
如果沒使用springboot的話,那麼需要添加依賴,並初始化對象
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.10.4</version>
</dependency>
如何在springboot中使用的,不用添加依賴,也可以不用自己實例化,使用spring容器已實例化的
objectMapper
,只要將對象交給容器管理,並注入對應的實列即可。
(當然了不用ioc容器的,自己創建一個實列也無可厚非)
2.工具類
主要以下幾個方法
- json轉對象
- 對象轉json(json格式化)
- json轉化爲泛型類型對象(集合等泛型方式)
package com.iworkh.test.restassured.utils;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
/**
* json轉化工具類
*
* @author: iworkh-沐雨雲樓
* @date: 2020-06-18
*/
public class JacksonTool {
private static final Logger LOGGER = LoggerFactory.getLogger(JacksonTool.class);
private final static ObjectMapper mapper;
static {
mapper = new ObjectMapper();
// 忽略json中在對象不存在對應屬性
mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
// 忽略空bean轉json錯誤
mapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
}
/**
* json轉對象
*
* @param jsonStr json串
* @param classType 對象類型
* @return 對象
*/
public static <T> T toEntity(String jsonStr, Class<T> classType) {
if (StringUtils.isEmpty(jsonStr)) {
LOGGER.warn("Json string {} is empty!", classType);
return null;
}
try {
return mapper.readValue(jsonStr, classType);
} catch (IOException e) {
LOGGER.error("json to entity error.", e);
}
return null;
}
/**
* json轉化爲帶泛型的對象
*
* @param jsonStr json字符串
* @param typeReference 轉化類型
* @return 對象
*/
public static <T> T toEntity(String jsonStr, TypeReference<T> typeReference) {
if (StringUtils.isBlank(jsonStr) || typeReference == null) {
return null;
}
try {
return (T) mapper.readValue(jsonStr, typeReference);
} catch (JsonProcessingException e) {
LOGGER.error("json to entity error.", e);
}
return null;
}
/**
* 對象轉json
*
* @param obj 對象
* @return json串
*/
public static String toJson(Object obj) {
if (obj instanceof String) {
return (String) obj;
}
try {
return mapper.writeValueAsString(obj);
} catch (IOException e) {
LOGGER.error("obj to json error.", e);
}
return null;
}
/**
* 對象轉json(格式化的json)
*
* @param obj 對象
* @return 格式化的json串
*/
public static String toJsonWithFormat(Object obj) {
if (obj == null) {
return null;
}
if (obj instanceof String) {
return (String) obj;
}
try {
return mapper.writerWithDefaultPrettyPrinter().writeValueAsString(obj);
} catch (IOException e) {
LOGGER.error("obj to json error.", e);
}
return null;
}
}
3.調用
使用很簡單,主要注意下泛型對象的轉化使用 new TypeReference<List<UserVo>>() {})
public class JacksonToolTest {
@Test
public void testEntityToJson() {
String[] hobbies = {"football", "sing"};
UserVo user = new UserVo(1, "iworkh", System.currentTimeMillis(), false, Arrays.asList(hobbies));
String json = JacksonTool.toJson(user);
System.out.println(json);
}
@Test
public void testJsonToEntity() {
String json = "{\"id\":1,\"name\":\"iworkh\",\"birthday\":1592575139578,\"vip\":false,\"hobbies\":[\"football\",\"sing\"]}";
UserVo userVo = JacksonTool.toEntity(json, UserVo.class);
if (userVo != null) {
System.out.println(userVo.getName());
}
}
@Test
public void testListEntityToJson() {
String[] hobbies = {"football", "sing"};
UserVo user1 = new UserVo(1, "iworkh1", System.currentTimeMillis(), false, Arrays.asList(hobbies));
UserVo user2 = new UserVo(2, "iworkh2", System.currentTimeMillis(), false, Arrays.asList(hobbies));
ArrayList<UserVo> list = new ArrayList<>();
list.add(user1);
list.add(user2);
String json = JacksonTool.toJson(list);
System.out.println(json);
}
@Test
public void testJsonToListEntity() {
String json = "[{\"id\":1,\"name\":\"iworkh1\",\"birthday\":1592575376189,\"vip\":false,\"hobbies\":[\"football\",\"sing\"]}," + "{\"id\":2,\"name\":\"iworkh2\",\"birthday\":1592575376189,\"vip\":false,\"hobbies\":[\"football\",\"sing\"]}]";
List<UserVo> userList = JacksonTool.toEntity(json, new TypeReference<List<UserVo>>() {
});
userList.forEach(item -> {
System.out.println(item.getName());
});
}
}
更多內容可以關注:iworkh博客