JAVA中list与数组相互转换及数组去重

List转数组：

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

list.add("1");

list.add("2");

String[] strings = new String[list.size()];

list.toArray(strings);

数组转list：

（1） list不可加减

String[] studentIds = new String[] {"1","2"};

List<String> list = Arrays.asList(studentIds);

（2）list可加减

String[] studentIds = new String[] {"1","2"};

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

Collections.addAll(list, studentIds);

list.add("3");

list.remove("2");

数组去重：

String[] studentIds = new String[] {"1","1","2"};

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

for(String studentId : studentIds) {

//过滤掉重复的

if(!newStudentIds.contains(studentId)) {

newStudentIds.add(studentId);

}

}

String[] array =new String[newStudentIds.size()];

newStudentIds.toArray(array);