44 lines
1.3 KiB
Java
44 lines
1.3 KiB
Java
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package jTest;
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import java.util.HashMap;
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public class HasMapTest {
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public static void main(String[] args) {
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// 如果使用的是 Map 没用直接的 forEach
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HashMap<String, Object> hashMap = new HashMap<>();
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hashMap.put("a", 1);
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hashMap.put("b", 2);
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hashMap.put("c", 3);
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hashMap.put("d", 4);
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hashMap.put("e", 5);
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// 如果在这个Map中没用找到这个键返回默认的值 666
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System.out.println(hashMap.getOrDefault("n", 666));
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// 拿到a的键
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System.out.println(hashMap.get("a"));
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// 是否包含键 a
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System.out.println(hashMap.containsKey("a"));
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// 是否包含值
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System.out.println(hashMap.containsValue(1));
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// 遍历 hashMap
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hashMap.forEach((s, o) -> {
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System.out.println("key：" + s);
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System.out.println("value：" + o);
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});
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hashMap.entrySet().forEach(System.out::println);
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// 将所以的键都添加到 hashMap 中
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HashMap<String, Object> addAllMap = new HashMap<>();
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addAllMap.put("f", 6);
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addAllMap.put("g", 7);
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addAllMap.put("h", 8);
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addAllMap.put("i", 9);
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hashMap.putAll(addAllMap);
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System.out.println(hashMap);
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}
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}
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