question: public static StringBuilder buildCommonParams ( MultiValueMap < String , Object > paramMap , String encodeCharset ) { StringBuilder paramBuilder = new StringBuilder ( ) ; Set < String > keySet = paramMap . keySet ( ) ; for ( String key : keySet ) { List < Object > values = paramMap . getValues ( key ) ; for ( Object value : values ) { if ( value != null && value instanceof CharSequence ) { paramBuilder . append ( "&" ) ; try { paramBuilder . append ( URLEncoder . encode ( key , encodeCharset ) ) ; paramBuilder . append ( "=" ) ; paramBuilder . append ( URLEncoder . encode ( value . toString ( ) , encodeCharset ) ) ; } catch ( UnsupportedEncodingException e ) { Logger . e ( "Encoding " + encodeCharset + " format is not supported by the system" ) ; paramBuilder . append ( key ) ; paramBuilder . append ( "=" ) ; paramBuilder . append ( value . toString ( ) ) ; } } } } if ( paramBuilder . length ( ) > 0 ) paramBuilder . deleteCharAt ( 0 ) ; return paramBuilder ; }
target:  Split joint non form data.