方式一：
public class Tool {
private static Pattern linePattern = Pattern.compile("_(\\w)");
/** 下划线转驼峰 */
public static String lineToHump(String str) {
str = str.toLowerCase();
Matcher matcher = linePattern.matcher(str);
StringBuffer sb = new StringBuffer();
while (matcher.find()) {
matcher.appendReplacement(sb, matcher.group(1).toUpperCase());
}
matcher.appendTail(sb);
return sb.toString();
}
/** 驼峰转下划线(简单写法，效率低于{@link #humpToLine2(String)}) */
public static String humpToLine(String str) {
return str.replaceAll("[A-Z]", "_$0").toLowerCase();
}
private static Pattern humpPattern = Pattern.compile("[A-Z]");
/** 驼峰转下划线,效率比上面高 */
public static String humpToLine2(String str) {
Matcher matcher = humpPattern.matcher(str);
StringBuffer sb = new StringBuffer();
while (matcher.find()) {
matcher.appendReplacement(sb, "_" + matcher.group(0).toLowerCase());
}
matcher.appendTail(sb);
return sb.toString();
}
public static void main(String[] args) {
String lineToHump = lineToHump("f_parent_no_leader");
System.out.println(lineToHump);// fParentNoLeader
System.out.println(humpToLine(lineToHump));// f_parent_no_leader
System.out.println(humpToLine2(lineToHump));// f_parent_no_leader
}
}
不纠结""_"+matcher.group(0).toLowerCase()"的话，humpToLine2效率会比humpToLine高一些，看String#replaceAll方法源码即可。
方式二：
实体类：
1 import java.io.Serializable;
2 import lombok.AllArgsConstructor;
3 import lombok.Data;
4 import lombok.NoArgsConstructor;
5
6 @Data
7 @AllArgsConstructor
8 @NoArgsConstructor
9 public class User implements Serializable {
10 /**
11 *
12 */
13 private static final long serialVersionUID = -329066647199569031L;
14
15 private String userName;
16
17 private String orderNo;
18 }
帮助类：
1 import java.io.IOException;
2
3 import com.fasterxml.jackson.annotation.JsonInclude.Include;
4 import com.fasterxml.jackson.core.JsonProcessingException;
5 import com.fasterxml.jackson.databind.ObjectMapper;
6 import com.fasterxml.jackson.databind.PropertyNamingStrategy;
7
8 /**
9 * JSON的驼峰和下划线互转帮助类
10 *
11 * @author yangzhilong
12 *
13 */
14 public class JsonUtils {
15
16 /**
17 * 将对象的大写转换为下划线加小写，例如：userName-->user_name
18 *
19 * @param object
20 * @return
21 * @throws JsonProcessingException
22 */
23 public static String toUnderlineJSONString(Object object) throws JsonProcessingException{
24 ObjectMapper mapper = new ObjectMapper();
25 mapper.setPropertyNamingStrategy(PropertyNamingStrategy.SNAKE_CASE);
26 mapper.setSerializationInclusion(Include.NON_NULL);
27 String reqJson = mapper.writeValueAsString(object);
28 return reqJson;
29 }
30
31 /**
32 * 将下划线转换为驼峰的形式，例如：user_name-->userName
33 *
34 * @param json
35 * @param clazz
36 * @return
37 * @throws IOException
38 */
39 public static <T> T toSnakeObject(String json, Class<T> clazz) throws IOException{
40 ObjectMapper mapper = new ObjectMapper();
// mapper的configure方法可以设置多种配置（例如：多字段 少字段的处理）
//mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
41 mapper.setPropertyNamingStrategy(PropertyNamingStrategy.SNAKE_CASE);
42 T reqJson = mapper.readValue(json, clazz);
43 return reqJson;
44 }
45 }
单元测试类：
1 import java.io.IOException;
2
3 import org.junit.Test;
4
5 import com.alibaba.fastjson.JSONObject;
6 import com.fasterxml.jackson.core.JsonProcessingException;
7
8 public class JsonTest {
9
10 @Test
11 public void testToUnderlineJSONString(){
12 User user = new User("张三", "1111111");
13 try {
14 String json = JsonUtils.toUnderlineJSONString(user);
15 System.out.println(json);
16 } catch (JsonProcessingException e) {
17 e.printStackTrace();
18 }
19 }
20
21 @Test
22 public void testToSnakeObject(){
23 String json = "{\"user_name\":\"张三\",\"order_no\":\"1111111\"}";
24 try {
25 User user = JsonUtils.toSnakeObject(json, User.class);
26 System.out.println(JSONObject.toJSONString(user));
27 } catch (IOException e) {
28 e.printStackTrace();
29 }
30 }
31 }
测试结果：
1 {"user_name":"张三","order_no":"1111111"}
2
3 {"orderNo":"1111111","userName":"张三"}
分类: JAVA-杂项,json&jsonp
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