Jackson说明

Jackson说明

package com.stono.sboot2_chp4_jackson.controller;

import com.fasterxml.jackson.annotation.JsonAnyGetter;
import com.fasterxml.jackson.annotation.JsonView;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.stono.sboot2_chp4_jackson.entity.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Controller
public class DataBindController {
    @Qualifier("getObjectMapper")
    @Autowired
    ObjectMapper objectMapper;

    @RequestMapping("/updateUsers.json")
    @ResponseBody
    public String updateUsers(@RequestBody List<User> list) {
        StringBuilder builder = new StringBuilder();
        for (User user : list) {
            builder.append(user.getName()).append(" ");
        }
        return builder.toString();
    }

    @RequestMapping("/customize.json")
    @ResponseBody
    public String costomize() throws IOException {
        String jsonInput = "[{\"name\":\"stono\",\"id\":1},{\"name\":\"tom\",\"id\":2}]";
        JavaType type = getCollectionType(List.class, User.class);
        List<User> users = objectMapper.readValue(jsonInput, type);
        return String.valueOf(users.size());
    }

    public JavaType getCollectionType(Class<?> collectionClass, Class<?>... elementClasses) {
        return objectMapper.getTypeFactory().constructParametricType(collectionClass, elementClasses);
    }

    @JsonView(User.IdView.class)
    @RequestMapping("/id.json")
    @ResponseBody
    public User queryIds() {
        User user = new User();
        user.setId(1);
        user.setName("stono");
        return user;
    }

    @RequestMapping("/user.json")
    @ResponseBody
    public User user() {
        User user = new User();
        user.setId(1);
        user.setName("stono");
        return user;
    }

    @RequestMapping("/dept.json")
    @ResponseBody
    public Department getDepartment() {
        return new Department(1);
    }

    class Department{
        Map map = new HashMap();
        private int id;

        public Department(int id) {
            this.id = id;
            map.put("newAttr", 1);
        }

        @JsonAnyGetter
        public Map<String, Object> getOtherProperties() {
            return map;
        }

        public int getId() {
            return id;
        }

        public void setId(int id) {
            this.id = id;
        }
    }

}

package com.stono.sboot2_chp4_jackson.controller;

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import java.io.IOException;
import java.io.StringWriter;

@Controller
@RequestMapping("/stream")
public class JacksonStreamController {

    @Qualifier("getObjectMapper")
    @Autowired
    ObjectMapper objectMapper;

    @RequestMapping("/parser.json")
    @ResponseBody
    public String parser() throws IOException {
        String json = "{\"name\":\"stono\",\"id\":1}";
        JsonFactory f = objectMapper.getFactory();
        String key = null, value = null;
        JsonParser parser = f.createParser(json);
        JsonToken token = parser.nextToken();
        System.out.println("token1:"+token);
        token = parser.nextToken();
        System.out.println("token2:"+token);
        if (token == JsonToken.FIELD_NAME) {
            key = parser.currentName();
        }
        token = parser.nextToken();
        System.out.println("token3:"+token);
        value = parser.getValueAsString();
        parser.close();
        return  key+","+value;
    }

    @RequestMapping("/generator.html")
    @ResponseBody
    public String generate() throws IOException {
        JsonFactory f = objectMapper.getFactory();
        StringWriter sw = new StringWriter();
        JsonGenerator g = f.createGenerator(sw);
        g.writeStartObject();
        g.writeStringField("name","stono");
//        g.writeString("string");
        g.writeEndObject();
        g.close();
        return sw.toString();

    }
}