public class TestArrayToList {

public static void main(String[] args) {

// TODO Auto-generated method stub

// 数组转换为集合Array to List 将字符串数组转换为集合

String[] arr = new String[5];

arr[0] = "a";

arr[1] = "b";

arr[2] = "c";

arr[3] = "d";

arr[4] = "e";

List<String> list = new ArrayList<String>();

list = Arrays.asList(arr);

// 将集合转换为数组

List<String> testList = new ArrayList<String>();

testList.add("A");

testList.add("B");

testList.add("C");

testList.add("D");

testList.add("E");

Object[] objects = testList.toArray();

// 循环遍历数组,获取到数组里面的值

String objectString = "";

for (int o = 0; o < objects.length; o++) {

objectString += objects[o].toString();

}

System.out.println("objectString:" + objectString);

// 将list转换为字符串

String listString = "";

for (int i = 0; i < list.size(); i++) {

listString += list.get(i);

}

System.out.println("listString:" + listString);

// 将数组转换为字符串

String arrString = StringUtils.join(arr);

System.out.println("arrString:" + arrString);

// 对象数组转换为对象集合 JSONArray JSOBObject之间的关系 JSONObject相当于是一个对象,JAONArray就是一个对象数组

// 1.通过JSONObject将String 转换为实体类

Size s = JSONObject.parseObject("{page:123,size:456}", Size.class);

System.out.println("s.getPage():" + s.getPage());

System.out.println("s.getSize():" + s.getSize());

// 对象数组

JSONArray array = JSONArray.parseArray("[{page:123,size:456},{page:112233,size:445566},{page:111222333,size:444555666}]");

System.out.println("array:" + array);

for (int i = 0; i < array.size(); i++) {

JSONObject object = (JSONObject) array.get(i);

System.out.println("object:" + object);

StringBuilder sb = new StringBuilder();

sb.append(object.get("size")).append(",").append(object.get("page"));

System.out.println("sb:" + sb);

}

// 一维对象数组转换为list的情况

// Size s1 = JSONObject.parseObject("[{page:123,size:456},{page:123,size:456},{page:123,size:456}]", Size.class);

JSONArray jsonArray1 = JSONArray.parseArray("[{page:123,size:456},{page:123,size:456},{page:123,size:456}]");// 把String转换为json

// 将JSONArray 转换为list

String jsonStr = JSONObject.toJSONString(jsonArray1);

List<String> aList = JSONObject.parseArray(jsonStr, String.class);

// 把list转换为String

String str4 = StringUtils.join(aList, ",");

System.out.println("str4:" + str4);

// 二维数组转换为list的情况

String string1 = "[[110121,110102,210120],[110121,110102,210120]]";

JSONArray jsonArray2 = JSONArray.parseArray(string1);// 把String转换为json

String jsonStr1 = JSONObject.toJSONString(jsonArray2);

List<List> aList1 = JSONObject.parseArray(jsonStr1, List.class);

String str5 = "";

for (int a = 0; a < aList1.size(); a++) {

str5 += StringUtils.join(aList1.get(a), ",") + (a == aList1.size() - 1 ? "" : "-");

}

System.out.println("str5:" + str5);

}

控制台输出:

objectString:ABCDE

listString:abcde

arrString:abcde

s.getPage():123

s.getSize():456

array:[{"size":456,"page":123},{"size":445566,"page":112233},{"size":444555666,"page":111222333}]

object:{"size":456,"page":123}

sb:456,123

object:{"size":445566,"page":112233}

sb:445566,112233

object:{"size":444555666,"page":111222333}

sb:444555666,111222333

str4:{"size":456,"page":123},{"size":456,"page":123},{"size":456,"page":123}

str5:110121,110102,210120-110121,110102,210120

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