我需要调用一个需要Pageable
字段的端点:
@GetMapping
public Page<ProductDTO> listProducts(Pageable pageable) {
return productService.findProducts(pageable);
}
在我的测试中,我有这段代码:
MultiValueMap<String, String> parameters = new LinkedMultiValueMap<>();
parameters.add("page", String.valueOf(0));
URI url = defaultURI(port, "/products", parameters);
ParameterizedTypeReference<RestResponsePage<ProductDTO>> type = new ParameterizedTypeReference<RestResponsePage<ProductDTO>>() {};
ResponseEntity<RestResponsePage<ProductDTO>> response = restTemplate.exchange(url.toString(), HttpMethod.GET, httpEntity, type);
PageImpl
不包含默认构造函数,所以为了避免这个问题,我创建了一个类,如下所示,传递给ParameterizedTypeReference
:
@JsonIgnoreProperties(ignoreUnknown = true) @Getter @Setter
public class RestResponsePage<T> extends PageImpl<T> implements Serializable {
private static final long serialVersionUID = 3844794233375694591L;
@JsonCreator(mode = JsonCreator.Mode.PROPERTIES)
public RestResponsePage(@JsonProperty("content") List<T> content,
@JsonProperty("number") int page,
@JsonProperty("size") int size,
@JsonProperty("totalElements") long totalElements) {
super(content, new PageRequest(page, size), totalElements);
}
public RestResponsePage(List<T> content, Pageable pageable, long totalElements) {
super(content, pageable, totalElements);
}
public RestResponsePage(List<T> content) {
super(content);
}
public RestResponsePage() {
super(new ArrayList<T>());
}
}
问题是我仍然收到以下错误:
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of org.springframework.data.domain.Pageable: abstract types either need to be mapped to concrete types, have custom deserializer, or contain additional type information
at [Source: java.io.PushbackInputStream@75564689; line: 38, column: 16] (through reference chain: com.shaunyl.util.ResponsePageImpl["pageable"])
为什么一直说我要传递一个抽象类? ResponsePageImpl
是一个类而不是抽象类。
谢谢
答案 0 :(得分:4)
package com.td.support;
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.databind.JsonNode;
import org.springframework.data.domain.PageImpl;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import java.util.ArrayList;
import java.util.List;
public class RestResponsePage<T> extends PageImpl<T> {
@JsonCreator(mode = JsonCreator.Mode.PROPERTIES)
public RestResponsePage(@JsonProperty("content") List<T> content,
@JsonProperty("number") int number,
@JsonProperty("size") int size,
@JsonProperty("totalElements") Long totalElements,
@JsonProperty("pageable") JsonNode pageable,
@JsonProperty("last") boolean last,
@JsonProperty("totalPages") int totalPages,
@JsonProperty("sort") JsonNode sort,
@JsonProperty("first") boolean first,
@JsonProperty("numberOfElements") int numberOfElements) {
super(content, PageRequest.of(number, size), totalElements);
}
public RestResponsePage(List<T> content, Pageable pageable, long total) {
super(content, pageable, total);
}
public RestResponsePage(List<T> content) {
super(content);
}
public RestResponsePage() {
super(new ArrayList<>());
}
}
上面的spring boot 2.0可能没问题。
答案 1 :(得分:0)
我找到了一种更优雅的方法来解决这个问题。其实是jackson序列化的问题。
首先定义一个jackson模块:
public class PageJacksonModule extends Module {
@Override
public String getModuleName() {
return "PageJacksonModule";
}
@Override
public Version version() {
return new Version(0,1,0, "", null,null);
}
@Override
public void setupModule(SetupContext context) {
context.setMixInAnnotations(Page.class, PageMixIn.class);
}
@JsonDeserialize(as = SimplePageImpl.class)
private interface PageMixIn{ }
static class SimplePageImpl<T> implements Page<T> {
private final Page<T> delegate;
public SimplePageImpl(
@JsonProperty("content") List<T> content,
@JsonProperty("page")int number,
@JsonProperty("size") int size,
@JsonProperty("totalElements") long totalElements){
delegate = new PageImpl<>(content, PageRequest.of(number, size), totalElements);
}
@JsonProperty
@Override
public int getTotalPages() {
return delegate.getTotalPages();
}
@JsonProperty
@Override
public long getTotalElements() {
return delegate.getTotalElements();
}
@JsonProperty("page")
@Override
public int getNumber() {
return delegate.getNumber();
}
@JsonProperty
@Override
public int getSize() {
return delegate.getSize();
}
@JsonProperty
@Override
public int getNumberOfElements() {
return delegate.getNumberOfElements();
}
@JsonProperty
@Override
public List<T> getContent() {
return delegate.getContent();
}
@JsonProperty
@Override
public boolean hasContent() {
return delegate.hasContent();
}
@JsonIgnore
@Override
public Sort getSort() {
return delegate.getSort();
}
@JsonProperty
@Override
public boolean isFirst() {
return delegate.isFirst();
}
@JsonProperty
@Override
public boolean isLast() {
return delegate.isLast();
}
@JsonIgnore
@Override
public boolean hasNext() {
return delegate.hasNext();
}
@JsonIgnore
@Override
public boolean hasPrevious() {
return delegate.hasPrevious();
}
@JsonIgnore
@Override
public Pageable nextPageable() {
return delegate.nextPageable();
}
@JsonIgnore
@Override
public Pageable previousPageable() {
return delegate.previousPageable();
}
@JsonIgnore
@Override
public <U> Page<U> map(Function<? super T, ? extends U> converter) {
return delegate.map(converter);
}
@JsonIgnore
@Override
public Iterator<T> iterator() {
return delegate.iterator();
}
}
}
然后注入它:
@Configuration
public class JacksonConfig {
@Bean
public Module pageJacksonModule() {
return new PageJacksonModule();
}
}
最后,您可以使用 Page
对象。
当然是测试:
@RunWith(SpringJUnit4ClassRunner.class)
@JsonTest
public class PageImplTest {
@Autowired
ObjectMapper mapper;
@Test
public void page() throws IOException {
String inputPageStr = "{\"content\":[{\"name\":\"n1\",\"gender\":\"boy\",\"age\":23},{\"name\":\"n2\",\"gender\":\"girl\",\"age\":20}],\"pageable\":\"INSTANCE\",\"totalPages\":1,\"last\":true,\"totalElements\":2,\"sort\":{\"sorted\":false,\"unsorted\":true,\"empty\":true},\"first\":true,\"numberOfElements\":2,\"size\":2,\"number\":0,\"empty\":false}";
Page<PageItem> pageItems = mapper
.readValue(inputPageStr, new TypeReference<Page<PageItem>>() {});
Assert.assertNotNull(pageItems);
}
static class PageItem {
private String name;
private String gender;
private int age;
public PageItem() {
}
public PageItem(String name, String gender, int age) {
this.name = name;
this.gender = gender;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
@Configuration
static class TestConfig{
@Bean
public Module pageJacksonModule() {
return new PageJacksonModule();
}
}
}