java遍历hashMap、hashSet、Hashtable

import java.io.File;import java.io.FileOutputStream;import java.util.Enumeration;import java.util.HashMap;import java.util.HashSet;import java.util.Hashtable;import java.util.Iterator;import java.util.Map;import java.util.Properties;import java.util.Set;import java.util.Map.Entry;//Java遍历集合public class Test {public static void main(String[] args) throws Exception {/** * String osArch = System.getProperty("os.arch"); String model = * System.getProperty("sun.arch.data.model"); String cpu = * System.getProperty("sun.cpu.isalist"); String vm_name = * System.getProperty("java.vm.name"); //java.vm.name=Java HotSpot(TM) * Client VM System.out.println(osArch); System.out.println(model); * System.out.println(cpu); */// traverseHashtable_property();// traverseHashMap();// traverseHashSet();traverseHashtable();}private static void traverseHashtable() {Hashtable<Object,Object> table = new Hashtable<Object, Object>();table.put(1, "11");table.put(2, "12");table.put(3, "13");// 遍历keyEnumeration e = table.keys();while (e.hasMoreElements()) {System.out.println(e.nextElement());}// 遍历valuee = table.elements();while (e.hasMoreElements()) {System.out.println(e.nextElement());}Set<Map.Entry<Object, Object>> entrys = table.entrySet();for (Entry<Object, Object> entry : entrys) {System.out.println(entry.getKey() + "=" + entry.getValue());}}// 遍历HashSetprivate static void traverseHashSet() {Set set = new HashSet();for (int i = 0; i < 100; i++) {set.add("123" + i);}for (Iterator it = set.iterator(); it.hasNext();) {System.out.println(it.next());}}// 遍历propertiesprivate static void traverseHashtable_property() throws Exception {Properties properties = System.getProperties();// 遍历hashtableStringBuilder sb = new StringBuilder();Set<Map.Entry<Object, Object>> entrys = properties.entrySet();for (Entry<Object, Object> entry : entrys) {sb.append(entry.getKey() + "=" + entry.getValue() + "\n");}System.out.print(sb.toString());File file = new File("log.txt");if (file.exists()) {file.delete();}writeTXT("log.txt", sb.toString());}/** 遍历HashMap */private static void traverseHashMap() {Map<Integer, String> map = new HashMap<Integer, String>();for (int i = 0; i < 100; i++) {map.put(i, "123" + i);}for (Entry<Integer, String> entry : map.entrySet()) {System.out.println(entry.getKey() + "=" + entry.getValue());}for (Object obj : map.keySet()) {Object key = obj;Object value = map.get(obj);System.out.print(key + "=" + value);}}private static void writeTXT(String filePath, String data) throws Exception {FileOutputStream outStream = new FileOutputStream(filePath);outStream.write(data.getBytes("UTF-8"));outStream.flush();outStream.close();}}