java下劃線與駝峰命名互轉
阿新 • • 發佈：2018-12-09
方式一：
下劃線與駝峰命名轉換：
-
public
class Tool {
-
private
static Pattern linePattern = Pattern.compile(
"_(\\w)");
-
-
/** 下劃線轉駝峰 */
-
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
-
}
-
matcher.appendTail(sb);
-
return sb.toString();
-
}
-
-
/** 駝峰轉下劃線(簡單寫法，效率低於{@link #humpToLine2(String)}) */
-
public static String humpToLine(String str) {
-
return str.replaceAll(
"[A-Z]",
"_$0").toLowerCase();
-
}
-
-
private
static Pattern humpPattern = Pattern.compile(
"[A-Z]");
-
-
/** 駝峰轉下劃線,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
-
}
-
}
不糾結""_"+matcher.group(0).toLowerCase()"的話，humpToLine2效率會比humpToLine高一些，看String#replaceAll方法原始碼即可。
方式二：
實體類：
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 }
幫助類：
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的駝峰和下劃線互轉幫助類 10 * 11 * @author yangzhilong 12 * 13 */ 14 public class JsonUtils { 15 16 /** 17 * 將物件的大寫轉換為下劃線加小寫，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 * 將下劃線轉換為駝峰的形式，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方法可以設定多種配置（例如：多欄位 少欄位的處理）
//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 }
單元測試類：
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("張三", "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\":\"張三\",\"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 }
測試結果：
1 {"user_name":"張三","order_no":"1111111"} 2 3 {"orderNo":"1111111","userName":"張三"}
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實體類：
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 }
幫助類：
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的駝峰和下劃線互轉幫助類 10 * 11 * @author yangzhilong 12 * 13 */ 14 public class JsonUtils { 15 16 /** 17 * 將物件的大寫轉換為下劃線加小寫，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 * 將下劃線轉換為駝峰的形式，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方法可以設定多種配置（例如：多欄位 少欄位的處理）
//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 }
單元測試類：
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("張三", "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\":\"張三\",\"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 }
測試結果：
1 {"user_name":"張三","order_no":"1111111"} 2 3 {"orderNo":"1111111","userName":"張三"}