कार्य कोड
public class PostgresJSONGsonBinding implements Binding<Object, JsonElement> {
// Binding <T> = Object (unknown JDBC type), and <U> = JsonElement (user type)
private static final Logger LOGGER = LoggerFactory.getLogger(PostgresJSONGsonBinding.class);
// The converter does all the work
@Override
public Converter<Object, JsonElement> converter() {
return new Converter<Object, JsonElement>() {
//Convert a database object to a user object
@Override
public JsonElement from(Object t) {
return t == null ? JsonNull.INSTANCE : new Gson().fromJson(t.toString(), JsonElement.class);
}
// Convert a user object to a database object
@Override
public Object to(JsonElement u) {
return u == null || u == JsonNull.INSTANCE ? null : new Gson().toJson(u);
}
@Override
public Class<Object> fromType() {
return Object.class;
}
@Override
public Class<JsonElement> toType() {
return JsonElement.class;
}
};
}
// Rending a bind variable for the binding context's value and casting it to the json type
@Override
public void sql(BindingSQLContext<JsonElement> ctx) throws SQLException {
// Depending on how you generate your SQL, you may need to explicitly distinguish
// between jOOQ generating bind variables or inlined literals.
if (ctx.render().paramType() == ParamType.INLINED){
ctx.render().visit(DSL.inline(ctx.convert(converter()).value())).sql("::json");
}
else{
ctx.render().sql("?::json");
}
}
// Registering VARCHAR types for JDBC CallableStatement OUT parameters
@Override
public void register(BindingRegisterContext<JsonElement> ctx) throws SQLException {
ctx.statement().registerOutParameter(ctx.index(), Types.VARCHAR);
}
// Converting the JsonElement to a String value and setting that on a JDBC PreparedStatement
@Override
public void set(BindingSetStatementContext<JsonElement> ctx) throws SQLException {
ctx.statement().setString(ctx.index(), Objects.toString(ctx.convert(converter()).value(), null));
}
// Getting a String value from a JDBC ResultSet and converting that to a JsonElement
@Override
public void get(BindingGetResultSetContext<JsonElement> ctx) throws SQLException {
ctx.convert(converter()).value(ctx.resultSet().getString(ctx.index()));
}
// Getting a String value from a JDBC CallableStatement and converting that to a JsonElement
@Override
public void get(BindingGetStatementContext<JsonElement> ctx) throws SQLException {
ctx.convert(converter()).value(ctx.statement().getString(ctx.index()));
}
// Setting a value on a JDBC SQLOutput (useful for Oracle OBJECT types)
@Override
public void set(BindingSetSQLOutputContext<JsonElement> ctx) throws SQLException {
throw new SQLFeatureNotSupportedException();
}
// Getting a value from a JDBC SQLInput (useful for Oracle OBJECT types)
@Override
public void get(BindingGetSQLInputContext<JsonElement> ctx) throws SQLException {
throw new SQLFeatureNotSupportedException();
}
}