about 5 years ago
在結合Spring跟jackson之後，幾乎所有的物件幾乎都可以自動幫你變成json資料格式輸出，
雖然有@JsonIgnore可以註解掉某些不想輸出的欄位，但有的時候需要有的時候不需要的話就要靠自訂過濾器來輔助了
1.先來看我們主要回覆的物件，裡面有關聯請退款紀錄
@Entity
@Table(name = "MORDER", catalog = "payment", uniqueConstraints = @UniqueConstraint(columnNames = {
"MERCHANTNUMBER", "TRANSNUMBER" }))
public class Morder implements java.io.Serializable {
// Fields
private String ordersn;
private String merchantnumber;
private String orgordernumber;
private Long transnumber;
private Integer orderamount;
// 退款紀錄
private Set<Morderrefund> morderrefunds = new HashSet<Morderrefund>(0);
// 請款紀錄
private Set<Morderdeposit> morderdeposits = new HashSet<Morderdeposit>(0);
private Notify notify;
// 其他略過
}
2.建立過濾器
import com.fasterxml.jackson.annotation.JsonFilter;
@JsonFilter("MorderQueryFilter")
public class MorderQueryFilter {
//底下是不想被轉成json的物件名稱
public static String[] ignorableFieldNames = { "morderdeposits", "morderrefunds" };
}
3.自訂輸出
原本你只需要像Spring與Jackson結合這篇將物件放入HashMap中讓他自動轉換，現在你必須透過ObjectMapper自己轉換好輸出
ObjectMapper mapper = new ObjectMapper();
mapper.addMixInAnnotations(Object.class, MorderQueryFilter.class);
FilterProvider filters = new SimpleFilterProvider().addFilter("MorderQueryFilter",SimpleBeanPropertyFilter.serializeAllExcept(MorderQueryFilter.ignorableFieldNames));
ObjectWriter writer = mapper.writer(filters);
try {
response.setContentType("text/html;charset=utf-8");
OutputStream os = response.getOutputStream();
os.write(writer.writeValueAsString(map).getBytes("utf-8"));
os.flush();
os.close();
} catch (Exception e) {
log.error("", e);
}
