使用流过滤POJO列表-获取ClassCastException java.util.LinkedHashMap不能强制转换

Question

尽管问题很熟悉，但我的问题有点奇怪。

这是我的POJO：

public class POJO implements Serializable {
    @JsonProperty("ID")
    private UUID id;

    @JsonProperty("Name")
    private String name;

    // getters and setters
}

List<POJO> pojoList = getListOfPojosFromSomeMethod();
List<POJO> filteredPOJO = pojoList.stream()
                          .filter(p -> p.getName().equals("POJOName"))
                          .collect(Collectors.toList())

java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to com.models.POJO
at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:174)
at java.util.ArrayList$ArrayListSpliterator.forEachRemaining (ArrayList.java:1374)
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
at 
java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
at 
java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499)

List<POJO> pojoList = getListOfPojosFromSomeMethod();
List<POJO> filteredPOJO = pojoList.stream()
                          .filter(p -> p.getName().equals("POJOName")
                          .map(p -> new POJO(p))
                          .collect(Collectors.toList());

Answer 1

您可以尝试：

Predicate<POJO> filterPredicate = item -> "POJOName".equals(item.getName());

List<POJO> filteredPOJOs = pojoList.stream()
                      .filter(filterPredicate)
                      .collect(Collectors.toList())