json jackson 是一个 java 库，它具有非常强大的数据绑定功能，并提供了一个将自定义 java 对象序列化为 json 以及将 json 反序列化回 java 对象的框架。我们可以转换json到/从map使用com.fasterxml.jackson.databind.objectmapper类的readvalue()和writevalueasstring()方法。
json 到映射语法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{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{"raja":"java technology", "vamsi":"web technology", "ravi":"python technology", "adithya":"spark technology"}
以上就是在java中使用jackson库将json转换为map或将map转换为json？的详细内容。