1、陣列

/*
 * @author willon
 * 陣列遍歷demo
 * 陣列的初始化必須有固定長度
 */


public class ArraytraversalDemo {
public static void main(String[] args) {
//未賦值的初始化
String[] array1 = new String[3];
//賦初值的初始化
String[] array2 = {"1","2,","c"};
//陣列賦值
array1[0] = "c";
array1[1] = "b";
array1[2] = "a";
//陣列重新賦值
array2[0] = "x";

//陣列取值
String index_value = array1[1];

//普通for迴圈遍歷
for(int i = 0 ; i< array1.length;i++){
System.out.println("array1的第"+(i+1)+"個值"+array1[i]);
}
//增強for迴圈遍歷
for(String value : array2){
System.out.println(value);
}
}
}

2. Json

import java.util.Iterator;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;

/*
 * @author Wilon.C
 * 
 */
public class JsonTraversalDemo {

public static void main(String[] args) {

//定義兩個String，分別為json格式，個jsonArray格式
String json = "{\"Name\":\"Wilon\",\"Age\":\"18\",\"Sex\":\"male\"}";
String jsonA = "[{\"Name\":\"Wilon\",\"Age\":\"18\",\"Sex\":\"male\"},{\"Name\":\"Wilon1\",\"Age\":\"16\",\"Sex\":\"male\"},{\"Name\":\"Wilon2\",\"Age\":\"120\",\"Sex\":\"female\"}]";

//
JSONObject jo = JSONObject.fromString(json);

JSONObject jsonDemo = null;
jsonDemo.put("key", "value");

Iterator<?> it = jo.keys();
while (it.hasNext()) {
String key = it.next().toString();
System.out.println(key + ":" +jo.get(key));
}


JSONArray ja = JSONArray.fromString(jsonA);
for (int i = 0 ; i < ja.length() ; i ++){
JSONObject jsonObject = ja.getJSONObject(i);
Iterator<?> it1 = jsonObject.keys();
while (it1.hasNext()) {
String key = it1.next().toString();
System.out.println("第" + i + "個JSONObject-" + key + ":" +jsonObject.get(key));
}
}
}
}

3. List

import java.util.ArrayList;
import java.util.List;


/*
 * @author Willon.C
 * list的初始化不需要指定長度
 * 
 */


public class ListTraversalDemo {

public static void main(String[] args) {
//list的初始化
List<String> listDemo = new ArrayList<String>();
//list加值
listDemo.add("fistElement");
listDemo.add("secondElement");
listDemo.add("thirdElement");
//list取值
String index_value = listDemo.get(0);
//list遍歷
for(int i = 0 ; i < listDemo.size() ; i ++){
System.out.println(listDemo.get(i));
}

//list賦值
listDemo.set(0, "new_firstElement");
//list增強for迴圈遍歷
for(String value : listDemo){
System.out.println(value);
}
}
}

4. Map

import java.util.HashMap;
import java.util.Map;

/*
 * @author Willon.C
 * Map的取值是無序的，有序的可以用LinkedMap
 */
public class MapTraversalDemo {
public static void main(String[] args) {
//Map初始化
Map<String, String> mapDemo = new HashMap<String,String>();
//Map加值
mapDemo.put("key1", "value1");
mapDemo.put("key2", "value2");
mapDemo.put("key3", "value3");
//Map取值
String value1 = mapDemo.get("key1");
//Map遍歷
for(String key : mapDemo.keySet()){
System.out.println(mapDemo.get(key));
}

}
}