TypeReference使用笔记

JSON字符串反序列化对象（单个对象）

@Slf4j
public class TypeReferenceTest{
    @Test
    public void parseObject(){
        String jsonContent = "{\"code\":\"200\",\"message\":\"error message\",\"data\":\"hello world\"}" ;
        TypeReference<RestResponse<String>> typeReference = new TypeReference<String>(){} ;
        RestResponse<String> response = JSON.parseObject(jsonContent, typeReference);
        log.info("====> response : {}", response);
    }
}
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ObjectMapper字符串反序列化（集合）

@SpringBootTest(classes = DynamicNacosApplication.class)
public class ObjectMapperTest {
    @Autowired
    private ObjectMapper objectMapper ;

    @Test
    public void collectionType() throws JsonProcessingException {
        String content = "...." ;
        CollectionType collectionType = objectMapper.getTypeFactory()
                .constructCollectionType(ArrayList.class, RouteDefinition.class);
        List<RouteDefinition> routeDefinitions = objectMapper.readValue(content, collectionType);
        routeDefinitions.forEach(item -> log.info("item : {}", item));
    }
}
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ObjectMapper字符串反序列化（集合）

@SpringBootTest(classes = DynamicNacosApplication.class)
public class ObjectMapperTest {
    @Autowired
    private ObjectMapper objectMapper ;

    @Test
    public void collectionType() throws JsonProcessingException {
        String content = "...." ;
 	   // other method
        List<RouteDefinition> infoCmds = 
 			objectMapper.readValue(jsonData, new TypeReference<List<RouteDefinition>>(){});
    }
}
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RestTemplate返回值泛型转换

@Slf4j
public class ParameterizedTypeReferenceTest {
    private RestTemplate restTemplate = new RestTemplate();

    @Test
    public void exchange(){
        String url = "http://localhost:8080/user-service/hello/index" ;
        ParameterizedTypeReference<RestResponse<String>> typeReference =
                new ParameterizedTypeReference<>() {} ;
        ResponseEntity<RestResponse<String>> exchange = 
             restTemplate.exchange(url, HttpMethod.GET, new HttpEntity<>(null), typeReference);
        RestResponse<String> retValue = exchange.getBody();
        log.info("ret value : {}", retValue);
    }
}
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