Jackson Full Data Binding: Difference between revisions
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Line 47: | Line 47: | ||
ByteArrayOutputStream baos = new ByteArrayOutputStream(); | ByteArrayOutputStream baos = new ByteArrayOutputStream(); | ||
ObjectMapper | |||
ObjectMapper mapper = new ObjectMapper(); | |||
Root root = ... // some hierarchical object | |||
mapper.writeValue(baos, root); | |||
System.out.println(new String(baos.toByteArray())); | System.out.println(new String(baos.toByteArray())); | ||
</pre> | </pre> |
Revision as of 21:48, 26 February 2017
Internal
Overview
JSON to Java
import com.fasterxml.jackson.databind.ObjectMapper; InputStream is = ...; ObjectMapper mapper = new ObjectMapper(); Root root = mapper.readValue(is, Root.class);
This is a generic conversion method, assuming that the JSON content matches the internal structure of the type <T>:
public static <T> T fromJson(String json, Class<? extends T> c) throws JsonConversionException { try { ObjectMapper objectMapper = new ObjectMapper(); return objectMapper.readValue(new ByteArrayInputStream(json.getBytes()), c); } catch (Exception e) { throw new JsonConversionException(e); } }
To enable generic type information (like "Map<String,Object>"), you have to use TypeReference container as explained above.
Java to JSON
ObjectMapper will introspect a Java object coded according to the Java Beans conventions and output it as JSON content.
The method names (without the "get") will be used as field names.
Example:
import com.fasterxml.jackson.databind.ObjectMapper; ByteArrayOutputStream baos = new ByteArrayOutputStream(); ObjectMapper mapper = new ObjectMapper(); Root root = ... // some hierarchical object mapper.writeValue(baos, root); System.out.println(new String(baos.toByteArray()));