如何使用Stream流操作将list中所有map的某个值拼接成字符串？

Question

将list中所有所有map的某个值用逗号隔开拼接成字符串，但是写的语句却报错了。

相关代码

List<Map> list =new ArrayList<>();

    Map<String,String> m =new HashMap();
    m.put("name","樟树街");

    Map<String,String> m1 =new HashMap();
    m.put("name","樟树街1");

    Map<String,String> m2 =new HashMap();
    m.put("name","樟树街1");
    
    list.add(m);
    list.add(m2);
    list.add(m1);
    
    //想把map中每一个名字用逗号隔开拼接个字符串，如果list中不是map而是个具体的实体则没问题
    String  s=  list.stream().map(p->p.get("name")).collect(Collectors.joining(","));

list.stream().map(p->p.get("name")).collect(Collectors.joining(",")); 会报错，请问要实现功能应该怎么写呢？

Answer 1

    Map<String,String> m =new HashMap();
    m.put("name","樟树街");

    Map<String,String> m1 =new HashMap();
    m.put("name","樟树街1");

    Map<String,String> m2 =new HashMap();
    m.put("name","樟树街1");

这一段内容插入的都在m里面....

修改后

package com.huifer.concurrence.issues;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class C {
    public static void main(String[] args) {
        List<Map<String, String>> list = new ArrayList<>();
        Map<String, String> m = new HashMap();
        m.put("name", "樟树街");

        Map<String, String> m1 = new HashMap();
        m1.put("name", "樟树街1");

        Map<String, String> m2 = new HashMap();
        m2.put("name", "樟树街1");

        list.add(m);
        list.add(m2);
        list.add(m1);

        String  s=  list.stream().map(p->p.get("name")).collect(Collectors.joining(","));
        System.out.println(s);
    }
}

Answer 2

没毛病啊这代码。

public static void main(String[] args) {

        List<Map<String, String>> list = new ArrayList<>(3);

        Map<String, String> m = new HashMap<>(1);
        m.put("name", "樟树街");

        Map<String, String> m1 = new HashMap<>(1);
        m1.put("name", "樟树街1");

        Map<String, String> m2 = new HashMap<>(1);
        m2.put("name", "樟树街2");

        list.add(m);
        list.add(m1);
        list.add(m2);

        String s = list.stream()
                .map(p -> p.get("name"))
                .collect(Collectors.joining(","));

        System.out.println(s);
    }

Output:

樟树街,樟树街1,樟树街2