Jacksonよくある使い方メモ ref: https://qiita.com/ques0942/items/c4a20a21c9e1f0963591

file0.java

public class SampleDTO {
    private String field1;
    private List<String> field2;
    private SomeClass field3;

    public String getField1(){return field1};
    public List<String> getField2(){return field2};
    public SomeClass getField3(){return field3};
    public String getField3Text(){return field3.getText()};
}

file1.java

SampleDTO dto = new SampleDTO();
ObjectMapper mapper = new ObjectMapper();
String json = mapper.writeValueAsString(dto);

file2.java

SampleDTO dto = new SampleDTO();
ObjectMapper mapper = new ObjectMapper();
ObjectNode jsonNode = mapper.valueToTree(dto);

file3.java

SampleDTO dto = new SampleDTO();
ObjectMapper mapper = new ObjectMapper();
ObjectReader reader = mapper.readerForUpdating(dto);
reader.readValue(json);

file4.java

@JsonIgnore
private String field1;

file5.java

@JsonProperty("fieldA")
private String field1;

file6.java

@JsonProperty("fieldA")
public String getField1(){
...
}

// JsonPropertyで設定した値とコンフリクトするメソッドが存在する場合は
// 不要な方にJsonIgnoreを付与する。
@JsonIgnore
public String getFieldA(){
...
}

// この場合setterも合わせて定義しないとうまく相互変換できない
@JsonSetter("fieldA")
public void setField1(String field1){
...
}

file7.java

private String sampleField;

file8.java

ObjectMapper mapper = new ObjectMapper();
// 命名変更規則の設定  
mapper.setPropertyNamingStrategy(PropertyNamingStrategy.CAMEL_CASE_TO_LOWER_CASE_WITH_UNDERSCORES);

file9.java

// 出力するJSON
mapper.enable(SerializationConfig.Feature.INDENT_OUTPUT);