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java?map的key值轉(zhuǎn)駝峰命名的方法

更新時(shí)間：2023年12月04日 08:58:46 作者：寒冷的雨呢

這篇文章主要介紹了java?map的key值轉(zhuǎn)駝峰,通過(guò)實(shí)例代碼介紹了Map把“_”形式的key轉(zhuǎn)化為駝峰形式，本文通過(guò)實(shí)例代碼給大家介紹的非常詳細(xì)，需要的朋友可以參考下

java map的key值轉(zhuǎn)駝峰

MPJLambdaWrapper<Entity> wrapper = new MPJLambdaWrapper<Entity>();
baseMapper.selectJoinMaps(wrapper).stream().map(MapUtil::toCamelCaseMap).collect(Collectors.toList());

List<Map<String, Object>> getList(DateAndAreaDto dateAndAreaDto);
return Result.success(scaleoperateMapper.getList(dateAndAreaDto)
                .stream()
                .map(MapUtil::toCamelCaseMap)

             map.stream()
                .map(MapUtil::toCamelCaseMap)
                .collect(Collectors.toList())

Java 把map的key轉(zhuǎn)換成駝峰命名

需求：將map里的key轉(zhuǎn)換為駝峰命名，并返回

package com.enation.app.javashop.framework.util;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
/**
 * map工具類
 *
 * @author 
 * @date 2021/8/31 12:57
 */
public class MapUtils {
    /**
     * 把map的key轉(zhuǎn)換成駝峰命名
     *
     * @param map
     * @return map
     */
    public static Map<String, Object> toReplaceKeyLow(Map<String, Object> map) {
        Map<String, Object> reMap = new HashMap<>();
        if (reMap != null) {
            Iterator var2 = map.entrySet().iterator();
            while (var2.hasNext()) {
                Entry<String, Object> entry = (Entry) var2.next();
                reMap.put(underlineToCamel((String) entry.getKey()), map.get(entry.getKey()));
            }
            map.clear();
        }
        return reMap;
    }
    public static final char UNDERLINE = '_';
    public static String underlineToCamel(String param) {
        if (param == null || "".equals(param.trim())) {
            return "";
        }
        int len = param.length();
        StringBuilder sb = new StringBuilder(len);
        for (int i = 0; i < len; i++) {
            char c = param.charAt(i);
            if (c == UNDERLINE) {
                if (++i < len) {
                    sb.append(Character.toUpperCase(param.charAt(i)));
                }
            } else {
                sb.append(Character.toLowerCase(param.charAt(i)));
            }
        }
        return sb.toString();
    }
}

Map把“_”形式的key轉(zhuǎn)化為駝峰形式

常見與數(shù)據(jù)庫(kù)獲取數(shù)據(jù)，key為字段名

package com.neusoft.modules.generator.handler;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.text.DecimalFormat;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import org.apache.commons.lang.StringUtils;
/**
 * map工具類
 *
 * @author 
 * @date 2021/8/31 12:57
 */
public class MapUtil {
    /**
     * 把map的key轉(zhuǎn)換成駝峰命名
     *
     * @param map
     * @return map
     */
    public static Map<String, String> toReplaceKeyLow(Map<String, String> map) {
    	if(null == map)
    	return null;
        Map<String, String> reMap = new HashMap<>();
        if (reMap != null) {
            Iterator var2 = map.entrySet().iterator();
            while (var2.hasNext()) {
                Entry<String, String> entry = (Entry) var2.next();
                String value= String.valueOf(map.get(entry.getKey()));
                if(value.indexOf("0E-")!=-1)
                {
                	value = "0";
                }
                if(value.equals("null"))
                {
                	value = "";
                }
                //將小數(shù)后面的“0”去掉，保留2位小數(shù)
                if(validateNumber(value))
                {
//                	System.out.println("value = " +value);
                	DecimalFormat decimalFormat = new DecimalFormat("###.##");
//                	String str = value.substring(0,5);
//                	if (str.equals("0.005")) {
//                	    value = "0.01";
//                    } else {
                        value = decimalFormat.format(Float.valueOf(value).floatValue());
//                    }
                }
                reMap.put(underlineToCamel((String) entry.getKey()),value);
            }
            map.clear();
        }
        return reMap;
    }
    public static final char UNDERLINE = '_';
    public static String underlineToCamel(String param) {
        if (param == null || "".equals(param.trim())) {
            return "";
        }
        int len = param.length();
        StringBuilder sb = new StringBuilder(len);
        for (int i = 0; i < len; i++) {
            char c = param.charAt(i);
            if (c == UNDERLINE) {
                if (++i < len) {
                    sb.append(Character.toUpperCase(param.charAt(i)));
                }
            } else {
                sb.append(Character.toLowerCase(param.charAt(i)));
            }
        }
        return sb.toString();
    }
    public static <T> List<T> deepCopy(List<T> src)
            throws IOException, ClassNotFoundException
        {
            ByteArrayOutputStream byteOut = new ByteArrayOutputStream();
            ObjectOutputStream out = new ObjectOutputStream(byteOut);
            out.writeObject(src);
            ByteArrayInputStream byteIn = new ByteArrayInputStream(byteOut.toByteArray());
            ObjectInputStream in = new ObjectInputStream(byteIn);
            return (List<T>)in.readObject();
        }
    //判斷該數(shù)據(jù)是否為小數(shù)形式
    private static boolean validateNumber(String str) {
        if(StringUtils.isBlank(str)||str.indexOf(".")==-1) {
          return false;
        }
        // 說(shuō)明一下的是該正則只能識(shí)別4位小數(shù)；如果不限制小數(shù)位數(shù)的話，寫成[+-]?[0-9]+(\\.[0-9]+)?就可以了
        return str.matches("[+-]?[0-9]+(\\.[0-9]+)?");  
    }
}

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