java 从给定的字符串URL中提取参数值

java 从给定的字符串URL中提取参数值

从给定的url中提取某个参数的值，如：
String url = “https://editor.csdn.net/md/hs/market/category?native_fullscreen=1xxc&hasBack=1&pageIndex=1”;
提取 pageIndex的值为1，native_fullscreen的值为 “1xxc”

---

实现思路：

1.可以通过字符串截取，url.indexOf(“pageIndex”),url.substring(index, index + 1) 等方式；
缺点是：不够灵活，硬编码多，通用性差。

2.通过正则表达式提取。

参考代码

public static String getParamByUrl(String url, String name) {
    
    
        url += "&";
        String pattern = "(\\?|&){1}#{0,1}" + name + "=[a-zA-Z0-9]*(&{1})";
        Pattern r = Pattern.compile(pattern);
        Matcher matcher = r.matcher(url);
        if (matcher.find()) {
    
    
            return matcher.group(0).split("=")[1].replace("&", "");
        } else {
    
    
            return "";
        }
    }

demo实例：

    public static void main(String []args) {
    
    
  
		String url = "/hs/market/category?native_fullscreen=1xxc&hasBack=1&pageIndex=1";
		int index = url.indexOf("pageIndex=");
		//int num = Integer.valueOf(url.charAt(index + "pageIndex=".length()));
		int start = index + "pageIndex=".length();
		String sum = url.substring(start, start +1);
		System.out.println("---sum:" + sum);
		int n = Integer.valueOf(sum);
		System.out.println("---index:" + index);
		System.out.println("---start:" + start);
		System.out.println("---n:" + n);
		
		String page = getParamByUrl(url, "pageIndex");
		System.out.println("---page:" + page);
		String native_fullscreen= getParamByUrl(url, "native_fullscreen");
		System.out.println("---native_fullscreen:" + native_fullscreen);
    }

输出：

—sum:1
—index:53
—start:63
—n:1
—page:1
—native_fullscreen:1xxc