day17

src/main/java/com/sf/day17/Test01.java

@@ -2,20 +2,90 @@ package com.sf.day17;
 
 import org.junit.Test;
 
-import java.util.HashMap;
-import java.util.Map;
+import java.util.*;
 
 public class Test01 {
     @Test
     public void t1(){
-        Map<String, String> map = new HashMap<String, String>();
-        map.put("username","zhangsan");
-        map.put("username1","zhangsan");
-        map.put("username2","zhangsan");
-        map.put("username3","zhangsan");
-        for (Map.Entry<String, String> entry : map.entrySet()) {
-            System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());
+       Map<String,Object> map = new HashMap<>();
+       //map的添加方法
+       map.put("username","admin");
+       map.put("password","123456");
+       System.out.println(map);
+
+        map.put("username","admin1");
+        System.out.println(map);
+
+        //从map中获取数据
+        Object o = map.get("username");
+        System.out.println(o);
+
+        //map中删除数据   返回值是删除的key所对应的value值
+        Object username = map.remove("username");
+        System.out.println(username);
+        System.out.println(map);
+
+        map.put("age",19);
+        map.put("sex","男");
+        map.put("id",2323231);
+        map.put("weight",190);
+
+        System.out.println(map);
+        //获取当前map集合中的所有key
+        Set<String> keys = map.keySet();
+        for (String string : keys) {
+            System.out.println("key==="+string+"======value"+map.get(string));
+        }
+
+        System.out.println("通过Map.entrySet使用iterator遍历key和value：");
+        Iterator<Map.Entry<String, Object>> iterator = map.entrySet().iterator();
+        while (iterator.hasNext()){
+//            System.out.println(iterator.next());
+            Map.Entry<String, Object> next = iterator.next();
+            System.out.println(next);
+            System.out.println(next.getKey()  +"+++++++++++++"+next.getValue());
         }
 
+        System.out.println("通过Map.entrySet遍历key和value");
+        for (Map.Entry<String, Object> stringObjectEntry : map.entrySet()) {
+            System.out.println(stringObjectEntry);
+        }
+
+        //只能获取values
+        Collection<Object> values = map.values();
+        System.out.println("===================================");
+        for (Object value : values) {
+            System.out.println(value);
+        }
+    }
+
+    @Test
+    public void t2(){
+        Map<String,Object> map = new HashMap<>();
+        Map<String,Object> map1 = new HashMap<>();
+        map.put("陈泽","国服天使");
+        map.put("name","zhangsan");
+        map.put("age",19);
+        map1.put("sex","男");
+        map.putAll(map1);
+        System.out.println(map);
+        Object val = map.remove("陈泽");
+        System.out.println(val);
+        System.out.println(map);
+//        map.clear();
+//        System.out.println(map);
+        System.out.println("====================");
+        System.out.println(map.get("name"));
+        System.out.println(map.containsKey("name"));
+        System.out.println(map.containsValue("zhangsan"));
+        System.out.println(map.size());
+        System.out.println(map.isEmpty());
+        System.out.println(map.equals(map1));
+
+        Set<String> strings = map.keySet();
+        System.out.println(strings);
+        System.out.println(map.values());
+        System.out.println(map.entrySet());
     }
 }
+