Android, using JSON to send data, using the Java escape character Kankan original

Last Update:2016-03-01 Source: Internet

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Kankan OriginalWhen sending data to and from the PHP background. This format is Required. private void Sendjson () { Initialize the handler of your own definitionCashhandler handler = new Cashhandler (this); Request a primary Address. Written in your own definition application, followed by the interface Name. String url = mapplication.get (). getappserviceurl () + "order/submit"; The Send request method that you define lreqentity entity = new Lreqentity (); Entity.seturl (url); lreqentity, The Post Method. The format of the number of passes is map (string,string)map<string, string> map = new hashmap<string, string> ();Stitching stringsStringBuffer params = new StringBuffer (); Jumpkey is 7 from the Point Mall and is purchased from the Point Mall If (jumpkey.equals ("7")) {Dbmanager is its own definition of database query methods. The enquiry is the purchase order of the shopping cart finallylist<carteentity> cartlist = Dbmanager.get (). Queryfinalcarte ( userentity.id);Stitching stringsParams.append ("["); for (int i = 0; i < cartlist.size (); I++) { Carteentity scoreentity = new Carteentity (); scoreentity = Cartlist.get (i);The next line is the escape character. In order to send the time, splicing out "this character, with the escape character \"This sends the result {"A": 54}Params.append ("{\" a\ ":"); Params.append (scoreentity.id + ""); Params.append (","); Params.append ("\" b\ ":"); Params.append (scoreentity.buycount); Params.append (","); Params.append ("\" c\ ":"); Params.append ("\" score\ "}"); If (i < cartlist.size ()-1) { Params.append (","); } } Params.append ("]"); }Entity.setparams (map); Entity.setreqmode (reqmothed.post); Handler.startloadingdata (entity); } In this way, the effect of stitching requirements is achieved. http://192.168.100.180:85/service/order/submit? {a=[{"a": up, "b": 3, "c": "score"},{"a":, "b": 3, "c": "score"}], b=89} There are a lot of things about escape characters. Java Transit literal characters: The most is the first one. 1. Special Characters: 3 \": double-cited \ ': single citation \\: backslash 2. Eight binary escape sequence: \ + 1 to 3-bit 5 digits. Range ' \000 ' ~ ' \377 ' : null character 3.Unicode Escape character: \u + four hexadecimal digits; 0~65535 \u0000: NULL character 4. Control Characters: 5\ ' Single-argument characters\ \ backslash Character\ r Enter\ nthe line break\f Paper Change page\ t transverse jump lattice\b Backspace Point Escape:. ==> u002e escape of the Dollar Sign: $ ==> u0024 Escape of the symbol: ^ ==> u005e Escape of the opening brace: {==> u007b Escape of the left parenthesis: [==> u005b Escape of the left parenthesis: (==> u0028 Escape of the vertical bar: | ==> u007c The escape of the right parenthesis:) ==> u0029 Escape of Asterisk: * ==> u002a Plus escape: + ==> u002b Escape of question mark:? ==> u003f Backslash escape: = = > u005c ====================================================================== The following program uses two Unicode escape characters, which represent Unicode characters in their hexadecimal code. so, What does this program print? Java code public class escaperout{ public static void main (string[] Args) { \U0022 is a Unicode escape character with two arguments System.out.println ("a\u0022.length () +\u0022b ". Length ()); } }public class escaperout{ public static void main (string[] Args) { \U0022 is a Unicode escape character with two arguments System.out.println ("a\u0022.length () +\u0022b ". Length ()); } } A very superficial analysis of the program would feel that it should print out 26, since there is a total of 26 characters between the strings identified by the two double-a\u0022.length () +\u0022b. A little bit deeper analysis will feel that the program should print 16, because two Unicode escape characters each in the source file needs to be represented by 6 Characters. however, they represent only one character in a string. So the string should be 10 characters shorter than it looks. Assuming you execute this program, you will find that it is far from the Case.It prints neither 26 nor 16. But 2.The key to understanding this puzzle is to know that Java does not provide any special handling of Unicode escape characters in string literal constants. The compiler converts the Unicode escape characters into the characters they represent [JLS 3.2] before parsing the program into various Symbols. therefore, the first Unicode escape character in the program is used as the ending argument for a single character string literal constant ("a"). The second Unicode escape character is used as the starting argument for a single character string literal constant ("b").The program prints the expression "a". length () + "b". length (), or 2.Assuming that the Program's author really wants this behavior, the following statements will be much clearer: Java code System.out.println ("a". length () + "b". length ());More likely, the author wants to place two double-digit characters inside the string literal constant.You cannot do this with Unicode escape characters, but you can use the escape character sequence to implement [JLS 3.10.6]. The escape character sequence that represents a double-argument is a backslash followed by a double-argument (\ "). Assuming that the Unicode escape character in the original program is replaced with an escape character sequence, it will print the expected 16 (error, which should be 14. Don't know how it's going to come out 16):Java code System.out.println ("a\". length () +\ "b". length ());Many characters have a sequence of escape characters, including a single (\), newline (\ n), tab (\ t), and backslash (\ \). You can use escape character sequences in character literal constants and string literal Constants. As a matter of fact. You can place any ASCII character in a string literal constant or a character literal constant by using a special type of escape character sequence called the octal escape character, but it is best to use the normal escape character sequence wherever possible.Both the normal escape character sequence and the octal escape character are much better than the Unicode escape character, and because unlike Unicode escape characters, the escape character sequence is processed after the program has been parsed into various symbols.ASCII is the minimum set of common attributes for a character set. It has only 128 characters, but Unicode has more than 65,000 characters. A Unicode escape character can be used to insert a Unicode character in a program that uses only ASCII Characters. A Unicode escape character is precisely equivalent to the character it Represents.The Unicode escape character is designed to be used in cases where a program ape needs to insert a character that cannot be represented in the source file character Set. They are primarily used to place non-ascii characters in identifiers, string literal constants, character literal constants, and Gaze.occasionally, Unicode escape characters are also used to clearly identify one of the several characters that appear to be quite similar. To add clarity to the Program.In summary, the escape character sequence is preferred in string and character literal Constants. Instead of the Unicode escape character. Unicode escape characters can cause confusion because they are prematurely processed in the compilation Sequence. Do not use Unicode escape characters to represent ASCII Characters.In string and character literal Constants. The escape character sequence should be used, and for cases other than these literal constants, the ASCII characters should be inserted directly into the source File. escape sequence meaning \ n Enter (\u000a) \ t horizontal tab (\u0009) \b Space (\u0008) \ r Line break (\u000d) \f (\u000c) \ ' single-pin (\u0027) \ "double-cited (\u0022) \ \ backslash (\u005c) \ddd three-bit octal \udddd four-bit hex Java brokered character: 1. Eight binary escape sequence: \ + 1 to 3 bit 5 digits; range ' \000 ' ~ ' \377 ' : null character 2.Unicode escape character: \u + four hexadecimal digits; 0~65535 \u0000: null character octal is 1 to 3 numbers and note the range of values, Assuming that the range is too large to compile incorrectly, hexadecimal escapes must be 4 hexadecimal digits. And some can not be escaped, such as ' \u000a '. Cannot be transferred, a compilation error occurs, and quite a number of numbers do not have the corresponding characters, just escaping to the question mark and escaping to the number, only if the range is not greater than the Scope. 3. Special Characters: 3 ": double-cited": single-quote \ \: Backslash 4. Control Character: 5 \ ' single-quote character \ \ backslash character \ r return \ n NewLine \f paper page change \ t horizontal jump lattice \b backspace Escape of Points:. ==> u002e Escape of Dollar Sign: $ ==> u0024 The escape of the symbol of the exponent: ^ ==> u005e Escape of opening curly brace: {==> u007b Escape of the left Parenthesis: [==> u005b Escape of the left Parenthesis: (==> u0028 Escape of Vertical Bars: | ==> u007c Escape of right parenthesis:) ==> u0029 Escape of Asterisks: * ==> u002a Escape of the plus sign: + ==> u002b Escape of question marks:? ==> u003f Anti-slash escape: ==> u005c Android, using JSON to send data, using the Java escape character Kankan original

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