package nc.util.TestClientTools;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* map集合遍历的五种方法
* @FileName: CircleMap.java
* @ClassName: nc.util.TestClientTools.CircleMap
* @Description: TODO(这里用一句话描述这个类的作用)
* @author chenfang
* @email ichenfang163@
* @date 2017-12-11 下午3:54:24
* @version V1.0
*
*/
//循环遍历map的五种方法
publicclass CircleMap {
publicstaticvoid main(String[] args) {
Map<String, Integer> tempMap = new HashMap<String, Integer>();
tempMap.put("a", 1);
tempMap.put("b", 2);
tempMap.put("c", 3);
// JDK1.4中
// 遍历方法一hashmap entrySet() 遍历
System.out.println("方法一");
Iterator it = tempMap.entrySet().iterator();
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
Object key = entry.getKey();
Object value = entry.getValue();
System.out.println("key=" + key + " value=" + value);
}
System.out.println("");
// JDK1.5中,应用新特性For-Each循环
// 遍历方法二
System.out.println("方法二");
for (Map.Entry<String, Integer> entry : tempMap.entrySet()) { String key = entry.getKey().toString();
String value = entry.getValue().toString();
System.out.println("key=" + key + " value=" + value);
}
System.out.println("");
// 遍历方法三hashmap keySet() 遍历
System.out.println("方法三");
for (Iterator i = tempMap.keySet().iterator(); i.hasNext();) { Object obj = i.next();
System.out.println(obj);// 循环输出key
System.out.println("key=" + obj + " value=" +
tempMap.get(obj));
}
for (Iterator i = tempMap.values().iterator(); i.hasNext();) { Object obj = i.next();
System.out.println(obj);// 循环输出value
}
System.out.println("");
// 遍历方法四treemap keySet()遍历
System.out.println("方法四");
for (Object o : tempMap.keySet()) {
System.out.println("key="+ o + " value="+ tempMap.get(o));
}
System.out.println("11111");
// java如何遍历Map <String, ArrayList> map = new HashMap <String,
// ArrayList>();
System.out.println("java 遍历Map <String, ArrayList> map = new HashMap<String, ArrayList>();");
Map<String, ArrayList> map = new HashMap<String, ArrayList>();
Set<String> keys = map.keySet();
Iterator<String> iterator = keys.iterator();
while (iterator.hasNext()) {
String key = iterator.next();
ArrayList arrayList = map.get(key);
for (Object o : arrayList) {
System.out.println(o + "遍历过程");
}
}
System.out.println("2222");
// 遍历方法五
Map<String, List> mapList = new HashMap<String, List>();
for (Map.Entry entry : mapList.entrySet()) {
String key = entry.getKey().toString();
List<String> values = (List) entry.getValue();
for (String value : values) {
System.out.println(key + " --> " + value);
}
}
}
}。