java 驼峰转换

﹏ヽ暗。殇╰゛Y 2022-07-11 07:42 239阅读 0赞

将"\_"转换成驼峰，将驼峰转换成"\_"。

import java.util.regex.Matcher;
    import java.util.regex.Pattern;
    
    /**
     * 驼峰转换
     * @author 胡汉三
     * 2017年1月19日 下午4:42:58
     */
    public class BeanHump {
    	
    	//转变的依赖字符
    	public static final char UNDERLINE='_';
    	
    	/**
    	 * 将驼峰转换成"_"(userId:user_id)
    	 * @param param
    	 * @return
    	 */
    	public static String camelToUnderline(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 (Character.isUpperCase(c)){  
    				sb.append(UNDERLINE);  
    				sb.append(Character.toLowerCase(c));  
    			}else{  
    				sb.append(c);  
    			}  
    		}  
    		return sb.toString();  
    	}
    	/**
    	 * 将"_"转成驼峰(user_id:userId)
    	 * @param param
    	 * @return
    	 */
    	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(c);  
    			}  
    		}  
    		return sb.toString();  
    	}
    	/**
    	 * 将"_"转成驼峰(user_id:userId)
    	 * @param param
    	 * @return
    	 */
    	public static String underlineToCamel2(String param){  
    		if (param==null||"".equals(param.trim())){  
    			return "";  
    		}  
    		StringBuilder sb=new StringBuilder(param);  
    		Matcher mc= Pattern.compile(UNDERLINE+"").matcher(param);  
    		int i=0;  
    		while (mc.find()){  
    			int position=mc.end()-(i++);  
    			String.valueOf(Character.toUpperCase(sb.charAt(position)));  
    			sb.replace(position-1,position+1,sb.substring(position,position+1).toUpperCase());  
    		}  
    		return sb.toString();  
    	} 
    	
    	/*
    	 * 测试
    	 */
    	public static void main(String[] args) {
    		System.out.println(camelToUnderline("userNameAll"));
    		System.out.println(underlineToCamel("user_name_all"));
    		System.out.println(underlineToCamel2("user_name_all"));
    	}
    }

运行结果：

![Center][]

[Center]: /images/20220711/de264c66e0a344079cd73d438dc0ab1e.png