本篇内容主要讲解“怎么用ObjectMapper将Map转换为实体类”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“怎么用ObjectMapper将Map转换为实体类”吧!

目录

  • ObjectMapper将复杂Map转为实体类

    • 背景

    • 1.使用ObjectMapper要添加的依赖是

    • 2.将复杂Map开始转换

  • objectMapper 解析复杂json toMap

    ObjectMapper将复杂Map转为实体类

    背景

    用fastjson转换复杂Map是浅层的可以转 深层的转换为null.，这时候可以用jackson来转。

    1.使用ObjectMapper要添加的依赖是

       <!--添加jackson包-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.8.3</version>
        </dependency>

    2.将复杂Map开始转换

    ObjectMapper mapper = new ObjectMapper();
Resource resource = mapper.convertValue(Map, Resource.class);

    注意的点：实体类中的字段是驼峰的 首字母不能大写。

    objectMapper 解析复杂json toMap

    public void parseSettings(){
        
        String settings = "{\"基本设置\":{\"name\":\"基本设置\",\"entries\":[{\"name\":\"站号\",\"type\":\"number\",\"description\":\"\",\"value\":\"1\"},{\"name\":\"AppEUI\",\"type\":\"string\",\"description\":\"\",\"value\":\"2C26C503A0010006\"},{\"name\":\"DevEUI\",\"type\":\"string\",\"description\":\"\",\"value\":\"4A7703A000FC09\"},{\"name\":\"命令次数\",\"type\":\"number\",\"description\":\"\",\"value\":\"2\"},{\"name\":\"父井号\",\"type\":\"string\",\"description\":\"\",\"value\":\"test11\"}]},\"油阀间\":{\"name\":\"油阀间\",\"entries\":[{\"name\":\"上传间隔时间\",\"type\":\"number\",\"description\":\"\",\"value\":\"2\"},{\"name\":\"设定值\",\"type\":\"number\",\"description\":\"\",\"value\":\"10\"},{\"name\":\"波动值\",\"type\":\"number\",\"description\":\"\",\"value\":\"1\"},{\"name\":\"控制模式\",\"type\":\"number\",\"description\":\"\",\"value\":\"0\"},{\"name\":\"调节上限\",\"type\":\"number\",\"description\":\"\",\"value\":\"15\"},{\"name\":\"调节下限\",\"type\":\"number\",\"description\":\"\",\"value\":\"5\"},{\"name\":\"调节时间\",\"type\":\"number\",\"description\":\"\",\"value\":\"10\"}]},\"采集调度\":{\"name\":\"采集调度\",\"entries\":[{\"name\":\"interval\",\"type\":\"number\",\"description\":\"\",\"value\":\"2\"}]}}";
        ObjectMapper objectMapper = new ObjectMapper();
        JavaType javaType = objectMapper.getTypeFactory().constructMapType(HashMap.class, String.class, SettingGroup.class);
        try {
            Map<String,SettingGroup>    mapSettings =    objectMapper.readValue(settings, javaType);
             SettingGroup group = mapSettings.get("基本设置");
             for (SettingEntry entry : group.getEntries()) {
                 System.out.println(entry.getName());                    
             }
            
             group = mapSettings.get("油阀间");
             for (SettingEntry entry : group.getEntries()) {
                 System.out.println("entry.Name:"+entry.getName()+" entry.getValue:"+entry.getValue());
             }
        } catch (JsonParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (JsonMappingException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }        
    }