使用Java中的Jackson库将JSON与Map进行相互转换？
JSONJackson是Java库，它具有非常强大的数据绑定功能，并提供了一个框架，可将自定义Java对象序列化为JSON并将JSON反序列化为Java对象。我们可以使用com.fasterxml.jackson.databind.ObjectMapper类的readValue() 和writeValueAsString()方法将JSON 与Map 进行相互转换 。
JSON映射
语法
public <T> T readValue(String content, TypeReference valueTypeRef) throws IOException, JsonParseException, JsonMappingException
示例
import java.io.*;
import java.util.*;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.core.type.TypeReference;
public class ConvertJSONToMapTest {
public static void main(String args[]) {
try {
ObjectMapper mapper = new ObjectMapper();
String jsonString = "{\"Name\":\"Raja\", \"Technology\":\"Java\"}";
Map<String, Object> jsonMap = new HashMap<String, Object>();
jsonMap = mapper.readValue(jsonString, new TypeReference<Map<String, String>>(){}); // converts JSON to Map
System.out.println(jsonMap);
} catch(IOException ie) {
ie.printStackTrace();
}
}
}输出结果
{Name=Raja, Technology=Java}映射到JSON
语法
public String writeValueAsString(Object value) throws JsonProcessingException
示例
import java.io.*;
import java.util.*;
import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.databind.ObjectMapper;
public class ConvertMapToJSONTest {
public static void main(String args[]) throws IOException {
ObjectMapper mapper = new ObjectMapper();
String jsonString = "";
Map<String, Object> map = new HashMap<String, Object>();
map.put("Raja", "Java Technology");
map.put("Ravi", "Python Technology");
map.put("Adithya", "Spark Technology");
map.put("Vamsi", "Web Technology");
jsonString = mapper.writeValueAsString(map); // converts Map to JSON System.out.println(map);
}
}输出结果
{"Raja":"Java Technology", "Vamsi":"Web Technology", "Ravi":"Python Technology", "Adithya":"Spark Technology"}