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使用POJO字段名将POJO转换为JsonNode

  •  0
  • Tejashwini  · 技术社区  · 7 年前

    要求:

    1. 将json文件中的选定字段收集到POJO中(字段名称不匹配)
    2. 更新POJO的其他未映射字段
    3. 使用POJO字段名转换回jsonNode

    问题: 步骤1和2很好。将POJO转换回JsonNode时,我无法在POJO字段名称中获取它。有谁能建议一种方法来达到这个目的吗?

    下面是我的代码

    @JsonIgnoreProperties(ignoreUnknown = true)
    public class MyPOJO {
    
    @JsonProperty("Firstname")
    private String name;
    
    @JsonProperty("Country")
    private String nationality;
    
    private String state;
    
    //getters and setters
    }
    

    思维方式

         ObjectMapper map = new ObjectMapper();
        JsonNode root =map.readTree(new Main().getResorceFile());
        List<MyPOJO> myList = new ArrayList<MyPOJO>();
    
        for(JsonNode each : root){
            MyPOJO myPOJO = new MyPOJO();
            myPOJO= map.readValue(each.toString(),MyPOJO.class);
            System.out.println(myPOJO.toString());
            myList.add(myPOJO);
        }
        for(MyPOJO p : myList){
            JsonNode node = map.convertValue(p,JsonNode.class);
            System.out.println((node.toString()));
        }
    

    Json文件

        {
            {
                "Firstname":"Tez",
                "Lastname":"Morris",
                "Country":"US"
            },
            {
                "Firstname":"Kip",
                "Lastname":"Lee",
                "Country":"US"
            },
            {
                "Firstname":"Pam",
                "Lastname":"Carr",
                "Country":"US"
            },
            {
                "Firstname":"lin",
                "Lastname":"Dale",
                "Country":"US"
            }
        }
    

    输出:

        Main{name='Tez', nationality='US', state='null'}
        Main{name='Kip', nationality='US', state='null'}
        Main{name='Pam', nationality='US', state='null'}
        Main{name='lin', nationality='US', state='null'}
        {"state":null,"Firstname":"Tez","Country":"US"}
        {"state":null,"Firstname":"Kip","Country":"US"}
        {"state":null,"Firstname":"Pam","Country":"US"}
        {"state":null,"Firstname":"lin","Country":"US"}
    

    预期产量

        Main{name='Tez', nationality='US', state='null'}
        Main{name='Kip', nationality='US', state='null'}
        Main{name='Pam', nationality='US', state='null'}
        Main{name='lin', nationality='US', state='null'}
        {"state":null,"name":"Tez","nationality":"US"}
        {"state":null,"name":"Kip","nationality":"US"}
        {"state":null,"name":"Pam","nationality":"US"}
        {"state":null,"name":"lin","nationality":"US"}
    
    1 回复  |  直到 7 年前
        1
  •  1
  •   mle    7 年前

    解决方案是将 @JsonProperty 在具有不同值的getter和setter上,例如:

    […]
    private String nationality;
    
    @JsonProperty("nationality")
    public String getNationality() {
        return nationality;
    }
    
    @JsonProperty("Country")
    public void setNationality(String nationality) {
        this.nationality = nationality;
    }
    […]
    

    getter执行序列化,setter执行反序列化。