java把字符串加上颜色 java中怎么给字符串加换行

public static String splitString(String content, int len) {
        String tmp = "";
         
         if (len > 0) {
             
             if (content.length() > len) {
                 
                 int rows = (content.length() + len - 1) / len;
                 
                 for (int i = 0; i < rows; i++) {
                     
                     if (i == rows - 1) {
                         
                         tmp += content.substring(i * len);
                     } 
                     else {
                         
                         tmp += content.substring(i * len, i * len + len) + "\r\n";
                     }
                 }
             } 
             else {
                 
                 tmp = content;
             }
         }        return tmp;
     }