java遍历Map

发表于 分类于
No.1 使用 Map.Entry
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import java.util.HashMap;
import java.util.Map;

public class TestMap01 {
    public static void main(String[] args) {

        Map<String, Object> map = new HashMap<String, Object>();
        map.put("zhangsan", 20);
        map.put("lisi", 50);

        for (Map.Entry<String, Object> entry : map.entrySet()) {
            System.out.println(entry.getKey() + "\t" + entry.getKey());
        }

    }
}
No.2 使用 forEach
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import java.util.HashMap;
import java.util.Map;

public class TestMap02 {
    public static void main(String[] args) {
        Map<String, Object> map = new HashMap<String, Object>();
        map.put("zhangsan", 20);
        map.put("lisi", 50);
        map.forEach((k, v) -> {
            System.out.println(k + "\t" + v);
        });
    }
}

No.3 使用迭代器(Iterator)遍历
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import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

public class TestMap03 {
    public static void main(String[] args) {
        Map<String, Object> map = new HashMap<String, Object>();
        map.put("zhangsan", 20);
        map.put("lisi", 50);
        Iterator<Map.Entry<String, Object>> entries = map.entrySet().iterator();
        while (entries.hasNext()) {
            Map.Entry<String, Object> entry = entries.next();
            System.out.println(entry.getKey() + "\t" + entry.getValue());
        }
    }
}