方法一：

package com.thinkgem.jeesite.modules.socketTest.demo2;

import java.util.HashMap;
import java.util.Map;

/**
 * @Author: zhouhe
 * @Date: 2019/4/11 11:21
 */
public class Test {
    public static void main(String[] args) {
        String arr = "##0261ST=31;CN=2011;PW=123456;MN=88888880000001";
        System.out.println(arr);

        Map map = new HashMap();

        if (null != arr) {
            String[] param = arr.split(";");
            for (int i = 0; i < param.length; i++) {
                int index = param[i].indexOf('=');
                map.put(param[i].substring(0,index), param[i].substring((index + 1)));
            }
        }
        System.out.println(map);
    }

}

方法二：

package com.thinkgem.jeesite.modules.socketTest.demo2;

import java.util.HashMap;
import java.util.Map;

/**
 * @Author: zhouhe
 * @Date: 2019/4/11 11:21
 */
public class Test {
    public static void main(String[] args) {
        String arr = "##0261ST=31;CN=2011;PW=123456;MN=88888880000001";
        Map result = new HashMap();
        String[] params = arr.split("\\;");
        for (String entry : params) {
            if (entry.contains("=")) {
                String[] sub = entry.split("\\=");
                if (sub.length > 1) {
                    result.put(sub[0], sub[1]);
                } else {
                    result.put(sub[0], "");
                }
            }
        }
        System.out.println(result);
        System.out.println(result.get("PW"));
    }

}