从列表中删除所有原因java.lang.UnsupportedOperationException

Question

我想将successList设置为[10,14]我试过的是，

String oneStr = "10,11,12,14";
String twoStr = "11,14";

Returns r = new Returns();

r.setFailureList(Arrays.asList(twoStr.split(",")));
r.setSuccessList(Arrays.asList(oneStr.split(",")));

r.getSuccessList().removeAll(r.getFailureList());
System.out.println(r.getSuccessList());

返回类是，

List<String> successList;
List<String> failureList;


public List<String> getSuccessList() {
    return successList;
}
public void setSuccessList(List<String> successList) {
    this.successList = successList;
}
public List<String> getFailureList() {
    return failureList;
}
public void setFailureList(List<String> failureList) {
    this.failureList = failureList;
}
public void setFailureList(ArrayList<String> failureList) {
    this.failureList = failureList;
}

并且导致java.lang.UnsupportedOperationException stackTrace，

Exception in thread "main" java.lang.UnsupportedOperationException
    at java.util.AbstractList.remove(Unknown Source)
    at java.util.AbstractList$Itr.remove(Unknown Source)
    at java.util.AbstractCollection.removeAll(Unknown Source)

Answer 1

来自asList()

的文档

  

返回由指定数组支持的固定大小的列表。

因此，当您直接修改（添加，删除..etc）时，最终会得到exception。

所以，但是在案例中

   new ArrayList<String>(Arrays.asList(twoStr.split(",")))

此处您不是直接引用list。您正在创建新的ArrayList并使用Arrays.as.asList(twoStr.split(","))返回的列表数据，该数据不是Unmodifiable（就大小而言）。

Answer 2

更改

r.setFailureList(Arrays.asList(twoStr.split(",")));
r.setSuccessList(Arrays.asList(oneStr.split(",")));

作为

r.setFailureList(new ArrayList<String>(Arrays.asList(twoStr.split(","))));
r.setSuccessList(new ArrayList<String>(Arrays.asList(oneStr.split(","))));