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json jackson不带setter反序列化对象

jackson java

ip696 · 技术社区 · 6 年前

我有课(例如。在实际项目中,我使用jaxb生成的类代替用户):

public class User {
  private List<String> users;

  public List<String> getUsers() {
    return users;
  }
}

当我得到用户user(带数据)时,我可以用jacksonjson将它序列化为string或byte[]。但是当我试图将它反序列化为 User 我得到错误:

Cannot construct instance of `javax.xml.bind.JAXBElement` (no Creators, like default construct, exist): cannot deserialize from Object value (no delegate- or property-based Creator)

因为用户没有setter。如何反序列化?

2 回复 | 直到 6 年前

GolamMazid Sajib 6 年前

您可以通过实现自定义反序列化程序类来实现。

试试这个:

String json = null;//your request json
ObjectMapper objectMapper = new ObjectMapper();
SimpleModule module = new SimpleModule();
module.addDeserializer(User.class,new UserDeserialzer());
User user = objectMapper.registerModule(module).readValue(json,User.class);

反序列化程序类:

public class UserDeserialzer extends JsonDeserializer<User>{
    @Override
    public User deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException {
        JsonNode value = new ObjectMapper().readTree(p.getText());
        User user = new User();
        try {
            Field field = user.getClass().getDeclaredField("users");
            field.setAccessible(true);
            field.set(user,value.get("users"));
        }catch (Exception ex){
        }
        return user;
    }
}

用于Spring Boot应用程序 :

添加此bean以全局反序列化。

@Bean
    public Jackson2ObjectMapperBuilder configureObjectMapper() {
        Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
        ObjectMapper objectMapper = new ObjectMapper();
        SimpleModule module = new SimpleModule();
        module.addDeserializer(User.class,new UserDeserialzer());
        objectMapper.registerModule(module);
        builder.configure(objectMapper);
        return builder;
    }

user8372096user8372096 6 年前

如果您希望在创建jaxb对象时使用apache cxf,那么可以在生成对象期间使用xjc插件自动创建setter getter方法。这样对你来说可能很实用。

我遇到了同样的问题,通过这种方式,我解决了问题,而没有进行代码更改。

您可以将以下部分添加到POM文件中:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.cxf</groupId>
            <artifactId>cxf-codegen-plugin</artifactId>
            <version>${version.apache.cxf}</version>
            <executions>
                <execution>
                    <id>generate-sources</id>
                    <phase>generate-sources</phase>
                    <configuration>
                        <sourceRoot>${basedir}/src/main/java</sourceRoot>
                        <wsdlOptions>
                            <wsdlOption>
                                <wsdl>${basedir}/src/main/resources/wsdl/sample.wsdl</wsdl>
                                <wsdlLocation>classpath:wsdl/sample.wsdl</wsdlLocation>
                                <extraargs>
                                    <extraarg>-xjc-Xbg</extraarg>
                                    <extraarg>-xjc-Xcollection-setter-injector</extraarg>
                                </extraargs>
                            </wsdlOption>
                        </wsdlOptions>
                    </configuration>
                    <goals>
                        <goal>wsdl2java</goal>
                    </goals>
                </execution>
            </executions>
            <dependencies>
                <dependency>
                    <groupId>org.apache.cxf.xjcplugins</groupId>
                    <artifactId>cxf-xjc-boolean</artifactId>
                    <version>3.0.3</version>
                </dependency>
                <dependency>
                    <groupId>org.andromda.thirdparty.jaxb2_commons</groupId>
                    <artifactId>collection-setter-injector</artifactId>
                    <version>1.0</version>
                </dependency>
            </dependencies>
        </plugin>
    </plugins>
</build>