如何自定义Jackson以反序列化包含${token}
的值?
这里是我想要从Apache Commons Configuration变量插值中添加的功能示例:
{
"file" = "${sys:user.home}/path/to/my_file"
}
如何自定义Jackson以反序列化包含${token}
的值?
这里是我想要从Apache Commons Configuration变量插值中添加的功能示例:
{
"file" = "${sys:user.home}/path/to/my_file"
}
JsonFactory
来覆盖JsonParser
的getText()
和getValueAsString()
方法。public class JacksonInterpolateString {
static final String JSON = "{ \"file\":\"${sys:user.home}/path/to/my_file\" }";
public static class Bean {
public File file;
@Override
public String toString() {
return file.toString();
}
}
private static class MyJsonParser extends JsonParserDelegate {
public MyJsonParser(final JsonParser d) {
super(d);
}
@Override
public String getText() throws IOException {
final String value = super.getText();
if (value != null) {
return interpolateString(value);
}
return value;
}
@Override
public String getValueAsString() throws IOException {
return getValueAsString(null);
}
@Override
public String getValueAsString(final String defaultValue) throws IOException {
final String value = super.getValueAsString(defaultValue);
if (value != null) {
return interpolateString(value);
}
return null;
}
}
private static class MyMappingJsonFactory extends MappingJsonFactory {
@Override
protected JsonParser _createParser(
final char[] data,
final int offset,
final int len,
final IOContext ctxt,
final boolean recyclable)
throws IOException {
return new MyJsonParser(super._createParser(data, offset, len, ctxt, recyclable));
}
@Override
protected JsonParser _createParser(final Reader r, final IOContext ctxt)
throws IOException {
return new MyJsonParser(super._createParser(r, ctxt));
}
}
private static String interpolateString(final String value) {
return value.replace("${sys:user.home}", "/home/user");
}
public static void main(String[] args) throws IOException {
final JsonFactory factory = new MyMappingJsonFactory();
final ObjectMapper mapper = new ObjectMapper(factory);
System.out.println(mapper.readValue(JSON, Map.class));
System.out.println(mapper.readValue(JSON, Bean.class));
}
}
{file=/home/user/path/to/my_file}
/home/user/path/to/my_file
String
,但如何在每个反序列化器类型(即Path)上应用转换?我认为我必须创建一个JsonParser
来覆盖getText
或getValusAsString
? - Guillaume LecrocJsonParser
卡住了,不知道有JsonParserDelegate
!对不起,声望不够,无法投票...所以+1。 - Guillaume Lecroc