10. The encoding apparatus according to claim 9 , wherein the generating unit is configured to: interchange first n characters in the first information group and the n boundary characters, delete the n boundary characters, and record, in at least first n bytes of the first information group, the type information and the position information that are of the n boundary characters to obtain the second information group, wherein the second information group comprises the m bytes; or delete the n boundary characters to obtain n idle bytes; move backward a character preceding the n th idle byte in the n idle bytes, so that remaining m-n characters in the first information group are recorded in consecutive bytes; and record, in at least first n bytes of the first information group, the type information and the position information that are of the n boundary characters to obtain the second information group, wherein the second information group comprises the m bytes.
10. The encoding apparatus according to claim 9 , wherein the generating unit is configured to: interchange first n characters in the first information group and the n boundary characters, delete the n boundary characters, and record, in at least first n bytes of the first information group, the type information and the position information that are of the n boundary characters to obtain the second information group, wherein the second information group comprises the m bytes; or delete the n boundary characters to obtain n idle bytes; move backward a character preceding the n th idle byte in the n idle bytes, so that remaining m-n characters in the first information group are recorded in consecutive bytes; and record, in at least first n bytes of the first information group, the type information and the position information that are of the n boundary characters to obtain the second information group, wherein the second information group comprises the m bytes. 11. The encoding apparatus according to claim 10 , wherein the generating unit is configured to: if n bytes occupied by the n boundary characters are sufficient to record the type information and the position information that are of the n boundary characters, record, in first n bytes of the first information group, the type information and the position information that are of the n boundary characters to obtain the second information group, wherein the second information group comprises the m bytes; or if n bytes occupied by the n boundary characters are not sufficient to record the type information and the position information that are of the n boundary characters, compress at least one character of the remaining m-n characters in the first information group, so as to make an idle bit appear in the front of the remaining m-n bytes, and record, in first n bytes of the first information group and in the idle bit, the type information and the position information that are of the n boundary characters to obtain the second information group, wherein the second information group comprises the m bytes.