1、GsonUtils

• Json字符串转对象
• 对象转Json字符串

@UtilityClass
@Slf4j
public class GsonUtils {private static final Gson GSON = new Gson();public static String toJsonStr(Object object) {return GSON.toJson(object);}public static String toJsonStr(Object obj, Type type) {return GSON.toJson(obj, type);}public static <T> T fromJson(String json, Class<T> classOfT) {return GSON.fromJson(json, classOfT);}public static <T> T fromJson(String json, Type typeOfT) {return GSON.fromJson(json, typeOfT);}public static String toJson(Object object) {try {return GSON.toJson(object);} catch (Exception e) {log.error("序列化失败", e);}return StringUtils.EMPTY;}
}

• 工具类使用

String str = "{\"status\":{\"code\":0,\"__isset_bit_vector\":[1]},\"poiId\":1}";TResponse tResponseA = GsonUtils.fromJson(str, TResponse.class);

2、String本身,可以加入日志信息

String.format("Duplicate asyncCreateTask request with requestId=%s, billNo=%s, finish it fast.", request.getRequestId(), request.getNo());

3、 Json和Map转换

map.put("0915", "1");
map.put("0916", "2");
String jsonStr = GsonUtils.toJsonStr(map);
Map<String,String> json2Map = GsonUtils.fromJson(jsonStr,new TypeToken<HashMap<String,String>>(){}.getType());

4、Date转为Json字符串

如果类中有Date类型的属性字段，则需要在创建gson的时候设置一下日期格式Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd").create();System.out.println(gson.toJson(new Date()));

5、Json和List转换

List<SkuDTO> list = GsonUtils.fromJson(jsonStr,new TypeToken<List<SkuDTO>>(){}.getType());List<Long> list2 = GsonUtils.fromJson(Lists.newArrayList(1L,2L), new TypeToken<List<Long>>() {}.getType());

6、 比较两个JSON字符串的不同

public void t() throws JSONException {String s1 = "{\"skuId\":1,\"skuName\":\"test\",\"temp\":2,\"address\":\"bj\"}";String s2 = "{\"skuId\":1,\"skuName\":\"test\",\"temp\":3,\"author\":\"mjp\"}";// 方式一：JSONCompareResult result  = JSONCompare.compareJSON(s1, s2, JSONCompareMode.STRICT);<dependency><groupId>org.skyscreamer</groupId><artifactId>jsonassert</artifactId><version>1.5.1</version><scope>test</scope></dependency>// 1中有2中没有System.out.println(result.isMissingOnField());List<FieldComparisonFailure> fieldMissing = result.getFieldMissing();for (FieldComparisonFailure fieldComparisonFailure : fieldMissing) {System.out.println(fieldComparisonFailure.getExpected());//address}// 2中有1中没有System.out.println(result.isUnexpectedOnField());List<FieldComparisonFailure> fieldUnexpected = result.getFieldUnexpected();for (FieldComparisonFailure fieldComparisonFailure : fieldUnexpected) {System.out.println(fieldComparisonFailure.getActual());//author}// 1中2中都有，但是val值不一样System.out.println(result.isFailureOnField());List<FieldComparisonFailure> list = result.getFieldFailures();for (FieldComparisonFailure fieldComparisonFailure : list) {System.out.println(fieldComparisonFailure.getField());//tempSystem.out.println(fieldComparisonFailure.getActual());//3System.out.println(fieldComparisonFailure.getExpected());//2}// 方式二：HashMap<String, Object> diffMap = Maps.newHashMap();Gson gson = new Gson();Map<String,Object> json1Map = gson.fromJson(s1,new TypeToken<HashMap<String,Object>>(){}.getType());Map<String,Object> json2Map = gson.fromJson(s2,new TypeToken<HashMap<String,Object>>(){}.getType());for (Map.Entry<String, Object> entry : json1Map.entrySet()) {String k1 = entry.getKey();Object v1 = entry.getValue();Object v2 = json2Map.get(k1);// 1中有2中没有if (v2 == null) {diffMap.put(k1, v1);continue;}// 1中2中都有，但是不一样if (!Objects.equals(v1, v2)){diffMap.put(k1, "expect:" + v1 + ", actual:" + v2);}}json2Map.forEach((k2, v2) -> {Object v1 = json1Map.get(k2);// 2中有1中没有if (v1 == null) {diffMap.put(k2, v2);}});System.out.println(diffMap);//{temp=expect:2.0, actual:3.0, address=bj, author=mjp}}

7、 字符串填充：生成单据号时填充

Long billType = 1L;
System.out.println("a" + StringUtils.leftPad(billType + "", 5, "0"));// a00001
即在billType的左侧补0，直到00001形成5位为止
右侧填充和两侧填充api如下：
public static String leftPad(final String str, final int size, String padStr)public static String center(String str, final int size, String padStr)

8、 String.format()的使用

参考：https://blog.csdn.net/lonely_fireworks/article/details/7962171

• 简单使用

int time = 3;
String nameParis = String.format("达到了最大次数%s次", time);

• 复杂使用

String contentFormat = "您今天售卖的【%s】支商品有较高可能发生售罄，预估销售损失pcs【%s】件，预估销售损失额【%s" +"】元，需联系补货，请点击“[及时处理|%s]”查看详情。";String url = "sell.out.warning.link:https://xxx.xxx.xxx" + ".com?warnType=%s&categoryId=%s"String result = String.format(contentFormat, skuCount, salePcs.stripTrailingZeros().toPlainString(),saleGmv.stripTrailingZeros().toPlainString(),String.format(url, warnType, categoryId));

1、将warnTpe和categoryId，填充到url中，成为一个完整的连接url

2、sku数，pcs，GMV，及时处理链接url 四个字端值，填充到contentFormat的%s中

9、截断字符串

String s = "大家好才是真的好";
String truncate = StringUtils.truncate(s, 2, 4);
System.out.println(truncate);//好才是真

10、split

https://www.runoob.com/java/java-string-split.html

isNotBlank 和 isNotEmpty的区别

public static boolean isNotEmpty(String str)：判断某字符串是否非空，这里不能排除空格字符，即StringUtils.isNotEmpty("  ") = true下面是示例：
StringUtils.isNotEmpty(null) = false
StringUtils.isNotEmpty("") = false
StringUtils.isNotEmpty(" ") = truepublic static boolean isNotBlank(String str)
判断某字符串是否不为空且长度不为0且不由空白符(whitespace)构成，即StringUtils.isNotBlank("  ") = false下面是示例：
StringUtils.isNotBlank(null) = false
StringUtils.isNotBlank("") = false
StringUtils.isNotBlank(" ") = false所以，在某些业务场景，用isNotBlank 比 isNotEmpty要好

11、判断字符串是否为Json字符串格式

try {JsonElement parse = new JsonParser().parse(extra);if (parse.isJsonObject() || parse.isJsonArray()) {//YES}
} catch (JsonSyntaxException e) {//ignore
}
// NO

12、deep copy

        // 对象deep copyMyUser myUser = new MyUser();myUser.setSkuId(1L);Gson gson = new Gson();MyUser newUser = gson.fromJson(gson.toJson(myUser), MyUser.class);System.out.println(newUser);myUser.setSkuId(77777777777L);System.out.println(newUser);// 集合deep copyList<MyUser> newList = JSON.parseArray(JSON.toJSONString(list), MyUser.class);//fastjsonSystem.out.println(newList);u1.setSkuId(777777777777777L);System.out.println(newList);

补充：关于msyql的Json格式

将json格式的内容存储mysql，mysql中字段为json而非Varchar

• 推荐5.7之后直接使用 字段名称 json
• 一般都用varchar(n) 注：n不要太大。太大的话考虑 JSON