wpcap 找不到指定的模块

Question

XelaNimed

Asked:2022-10-01 17:37:23 +0800 CST2022-10-01 17:37:23 +0800 CST 2022-10-01 17:37:23 +0800 CST

如何测试泛型方法？

772

在 Eclipse 2021-09 上使用 JUnit 4.12 测试getPatches(Object, Object)的公共类中有一个静态方法：JsonUtil

import javax.annotation.Nonnull;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;

public static List<PatchOperation> getPatches(
    @Nonnull Object oldData,
    @Nonnull Object newData)
    throws IOException
{
    List<PatchOperation> _patchOperations = new ArrayList<>();
    ObjectMapper objectMapper = new ObjectMapper();

    String _oldDataJson = objectMapper.writeValueAsString(oldData);
    String _newDataJson = objectMapper.writeValueAsString(newData);

    JsonNode _oldJsonNode = objectMapper.readTree(_oldDataJson);
    JsonNode _newJsonNode = objectMapper.readTree(_newDataJson);

    JsonNode _patchData = com.github.fge.jsonpatch.diff.JsonDiff.asJson(_oldJsonNode, _newJsonNode);
    if (_patchData != null)
    {
        _patchOperations = objectMapper.convertValue(_patchData, new TypeReference<List<PatchOperation>>(){});
    }

    return _patchOperations;
}

这里，PatchOperation只是一个 POJO 类，用于反序列化JSON-Patch（参见RFC6902），用于对服务器的PATCH 请求：

import java.io.Serializable;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

@JsonIgnoreProperties(ignoreUnknown = true)
@JsonInclude(JsonInclude.Include.NON_NULL)
public class PatchOperation implements Serializable
{
    private static final long serialVersionUID = 9999999999999999999L;
    
    @JsonProperty("op")
    public String Operation;
    
    @JsonProperty("path")
    public String Path;
    
    @JsonProperty("value")
    public Object Value;
    
    @JsonProperty("from")
    public String From;
    
    @Override
    public String toString() 
    {
        try
        {
            return new ObjectMapper().writeValueAsString(this);
        }
        catch ( JsonProcessingException e )
        {
            return super.toString();
        }
    }
}

方法的 JUnit 测试getPatches：

@Test public final void getPatchesTest()
            throws JsonProcessingException, IOException
{
    PatchTestItem _itemOne = new PatchTestItem();
    _itemOne.id = "ABC123";
    _itemOne.active = true;
    _itemOne.value = "First value";

    PatchTestItem _itemTwo = new PatchTestItem();
    _itemTwo.id = "ABC123";
    _itemTwo.active = true;
    _itemTwo.value = "Updated value";

    java.util.List<PatchOperation> _patches = JsonUtil.getPatches(_itemOne, _itemTwo);

    Assert.assertNotNull(_patches);
    Assert.assertEquals(1, _patches.size());
    // в следующей строке выбрасывает ошибку при тестировании обобщённого метода
    Assert.assertEquals("replace", _patches.get(0).Operation);
    Assert.assertEquals("/value", _patches.get(0).Path);
    Assert.assertEquals(_itemTwo.value, _patches.get(0).Value.toString());
    
    _itemTwo.value = _itemOne.value;
    _patches = JsonUtil.getPatches(_itemOne, _itemTwo);
    
    Assert.assertNotNull(_patches);
    Assert.assertEquals(0, _patches.size());
    
    _itemTwo.active = false;
    _itemTwo.value = "Updated value again";
    _patches = JsonUtil.getPatches(_itemOne, _itemTwo);
    
    Assert.assertNotNull(_patches);
}

测试正在运行，以这种形式一切都很好。
现在决定使用通用方法如下：

public static <T> List<T> getPatches(
    @Nonnull Object oldData,
    @Nonnull Object newData)
    throws IOException
{
    List<T> _patchOperations = new ArrayList<>();
    ObjectMapper objectMapper = new ObjectMapper();

    String _oldDataJson = objectMapper.writeValueAsString(oldData);
    String _newDataJson = objectMapper.writeValueAsString(newData);

    JsonNode _oldJsonNode = objectMapper.readTree(_oldDataJson);
    JsonNode _newJsonNode = objectMapper.readTree(_newDataJson);

    JsonNode _patchData = com.github.fge.jsonpatch.diff.JsonDiff.asJson(_oldJsonNode, _newJsonNode);
    if (_patchData != null)
    {
        _patchOperations = objectMapper.convertValue(_patchData, new TypeReference<List<T>>(){});
    }

    return _patchOperations;
}

上面的选项没有通过测试 - 它给出错误“找不到源”并掉入日志：

java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to xxx.xxx.xxx.xxx.xxx.PatchOperation
    at xxx.xxx.xxx.xxx.xxx.JsonUtilTest.getPatchesTest(JsonUtilTest.java:36)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:93)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:40)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:529)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:756)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:452)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:210)

当然，我知道问题是 JUnit 找不到类型，但是我应该如何以及如何更改以使测试运行？

1 个回答

Voted

XelaNimed · Answer 1 · 2022-10-04T14:38:37+08:00

Best Answer

XelaNimed

2022-10-04T14:38:37+08:002022-10-04T14:38:37+08:00

感谢罗马的澄清和帮助。在@RomanKonoval 的建议下，在方法中添加了一个参数，用于传递所需的类型信息：

public static <T> T getPatches(
    @Nonnull Object oldData,
    @Nonnull Object newData,
    final TypeReference<T> typeRef)
    throws IOException
{
    String _oldDataJson = objectMapper.writeValueAsString(oldData);
    String _newDataJson = objectMapper.writeValueAsString(newData);

    JsonNode _oldJsonNode = objectMapper.readTree(_oldDataJson);
    JsonNode _newJsonNode = objectMapper.readTree(_newDataJson);

    JsonNode _patchData = com.github.fge.jsonpatch.diff.JsonDiff.asJson(_oldJsonNode, _newJsonNode);
    return new ObjectMapper().convertValue(_patchData, typeRef);
}
// Пример использования:
// final TypeReference<List<PatchOperation>> _typeRef =
//       new TypeReference<List<PatchOperation>>() {};
// List<PatchOperation> _patches =
//       JsonUtil.getConvertedPatch(_itemOne, _itemTwo, _typeRef);

我很乐意接受建设性的批评和评论。

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