Résumé de Jackson des méthodes de sérialisation et de désérialisation génériques

Réimprimé à partir de: https://www.cnblogs.com/EasonJim/p/7919422.html

Remarque: Jackson peut fonctionner normalement pour les génériques simples, mais échoue parfois pour les classes génériques trop complexes. Actuellement à la recherche d'une bibliothèque Json plus appropriée. Cependant, ce point peut parfaitement résoudre ces problèmes dans la solution native dotnet JavaScriptSerializer, quelle que soit la complexité des génériques.

Les exemples sont les suivants:

package com.jsoft.springboottest.springboottest1.controller;

import java.io.IOException;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.jsoft.springboottest.springboottest1.Pager;
import com.jsoft.springboottest.springboottest1.PagerAppoint;
import com.jsoft.springboottest.springboottest1.User;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import sun.reflect.generics.reflectiveObjects.ParameterizedTypeImpl;

@RestController
public class TestController {

    private static final Logger logger = LoggerFactory.getLogger(TestController.class);

    @RequestMapping("/show")
    public String show() throws IOException {
        ObjectMapper mapper = new ObjectMapper();
        User user = new User();
        user.setId(1);
        Pager<User> pager = new Pager<User>();
        List<User> users = new ArrayList<User>();
        users.add(user);
        pager.setDatas(users);
        String json = mapper.writeValueAsString(pager);
        // 方式1
        Pager<User> userPager1 = mapper.readValue(json, new TypeReference<Pager<User>>() {
        });
        // 方式2
        Type[] types = new Type[1];
        types[0] = User.class;
        final ParameterizedTypeImpl type = ParameterizedTypeImpl.make(Pager.class, types, Pager.class.getDeclaringClass());
        TypeReference typeReference = new TypeReference<Pager>() {
            @Override
            public Type getType() {
                return type;
            }
        };
        Pager<User> userPager2 = mapper.readValue(json, typeReference);
        // 方式3
        JavaType javaType = mapper.getTypeFactory().constructParametrizedType(Pager.class, Pager.class, User.class);
        Pager<User> userPager3 = mapper.readValue(json, javaType);
        // 方式4
        JavaType javaType1 = mapper.getTypeFactory().constructParametricType(Pager.class, User.class);
        Pager<User> userPager4 = mapper.readValue(json, javaType1);
        // 方式5，新建另一个指定具体泛型T的参数的类
        PagerAppoint userPager5 = mapper.readValue(json, PagerAppoint.class);
        // 数组泛型的序列化和反序列化
        String json1 = mapper.writeValueAsString(users);
        JavaType javaType2 = mapper.getTypeFactory().constructParametricType(List.class, User.class);
        List<User> users1 = mapper.readValue(json1, javaType2);
        // HashMap
        Map<String, User> map = new HashMap<String, User>(16);
        map.put("test", user);
        String json2 = mapper.writeValueAsString(map);
        // 1
        Map<String, User> users2 = mapper.readValue(json2, new TypeReference<Map<String, User>>() {
        });
        // 2
        JavaType javaType3 = mapper.getTypeFactory().constructParametricType(HashMap.class, String.class, User.class);
        Map<String, User> users3 = mapper.readValue(json2, javaType3);

        return "hello world";
    }
}

Exemple de projet: https://github.com/easonjim/5_java_example/tree/master/springboottest/springboottest10

référence:

http://www.yiibai.com/jackson/jackson_data_binding_generics.html

http://blog.csdn.net/z69183787/article/details/46235905

http://bbs.csdn.net/topics/391823803

https://www.cnblogs.com/quanyongan/archive/2013/04/16/3024993.html

http://www.hankcs.com/program/json-to-map-java-demo-code.html

http://huangyunbin.iteye.com/blog/2352243

http://www.jianshu.com/p/ca03c2fe36e3

http://www.yiibai.com/jackson/jackson_data_binding_generics.html

http://bbs.csdn.net/topics/391823803

https://www.cnblogs.com/quanyongan/archive/2013/04/16/3024993.html