java coding book

(); byte[] bytes4 = S.getbytes ("Utf-16be"); //utf-8 Code Chinese occupies 3 bytes, English occupies 1 bytes for(byteb:bytes4) { //converts bytes to int to be displayed in 16 binary modeSystem.out.print (integer.tohexstring (BAMP;0XFF) + ""); } System.out.println (); /** When your byte sequence is some kind of encoding, this time you want to turn the byte sequence into a * string, also need to use this encoding method, no one will appear garbled*/String str1=NewString

, int[] R3, int[] R4) throws illegalargumentexception{Ensure the arrays is of equal size......}9) ToString methodIn general, each class should define a ToString method:Public String toString () {...}) Main methodGeneral class, consider placing a main () method that contains the code used to test the class, and if it contains the main () method, it should be written at the bottom of the class.4. Java Coding

we call the second position, the encoding in the page encoding declaration should be the same as the encoding used when the Web page file was saved. and the browser's coding settings are actually not strict, as we said in the third section, in the browser choose to use GB2312 to view, it will actually still use GBK. And the browser also has the good habit, that it will try to guess what to use the code to see the most appropriate. I would like to r

Here are some of the books I recommend to you based on years of reading and practical experience:Part I: Java language chapter1 Java Programming specificationStar:Suitable for: Beginner, IntermediateDescription: Author James Gosling (father of Java), so this book I think you have to read. The basic explanation is very

. Since I have set the operation as a high-level concept, more work can be done freely at the underlying runtime. For imperative objects, developers often consider using reusable classes because their language encourages classes as building blocks. Function programming languages tend to reuse functions. Functional Languages construct complex general functions (suchfilter(),map()Andreduce()) And can be customized by functions provided as parameters. In functional languages, it is common to conver

Java Coding Style:1. Factory method should be stateless.State normally refers to the member variables of class. Stateless, more precisely, it means immutable.Factory was just to create objects, and one call should not affect anothers, if it was mutable, then the method call Mnight The chance to the States.And then it would affect other calls which is not supposed to happen.2.Restrict the access level of any

member variable: Need to use GET, set method read, setting9.2. Important or repetitive expressions or methods should be extracted.9.2. Exception handling: Do not ignore any exception information. If you want to track more advanced exceptions, do not ignore the lower level exception information.9.3. Release resources: If you need to release resources, you need to put them in a finally block.Other references:Http://www.oracle.com/technetwork/java/codec

The norm needs to be noticed in the regular coding process, which is a good habit to develop slowly.1. Basic PrinciplesMandatory principle:1. The StringBuilder of the string must be used;The use of 2.try...catchTry {}catch{Exception e e.printstacktrace ();} finally {}// can be used in the outermost action, all other places are forbidden to use;Try { // program code }catch(Exception e) { // is empty, nothing is written } // prohibit use in any

Recently in a project, the overall project is to deal with the database, take out data to be submitted to an interface through the HTTP protocol. The specific function is not much to say, just talk about the inside of a point--coding problems In the project, it involves taking the MD5 value of all the data. In Java projects, individuals prefer to change the project's default encoding to UTF-8. The develop

public key, the public key and the private key belong to the message passing parties, carries on the encrypted message passing.Consider a scenario.A machine module needs to export the data to a file, send the file to the B machine, and import the data by B.In this scenario, a is equivalent to the server, which needs to give the certificate to B, encrypt the data with the private key, generate the signature, and export to the file.b corresponds to the client, using the received digital certifica

before the question, let's take a look at what is Url,uri and QueryString, as shown in 1:Figure 1:url-uri-querystringURL: is the acronym for the Global Resource Locator, as above localhost: refers to domain (IP or hostname), 8080: is the port Web service is generally 80,8080 is the use of its own test, to avoid and browser port conflicts.ROOT: Is the Contentpath, which is the virtual path, if the Tomcat server object is the Servlet: Is the Servletpath message, which corresponds to the Getspecial

Java inside the built-in strings are all UTF-16 encoding, detailed coding way to see hereimport Java.nio.charset.charset;import java.util.arrays;import java.util.Map; Public classString2bytes { Public Static voidMain (string[] args) {String str="\u005bab Me"; Mapcharset.availablecharsets (); for(String charsetName:charsetMap.keySet ()) {System. out. println (CharsetName +":"+ Charsetmap.Get(CharsetName));

"); System.out.println (Sunicode);//6, GBK encoded string SGBK = new String (BYTESGBK, "GBK"); System.out.println (SGBK);//If the restore by other encoding, there is garbled//1, UTF-16 encoding decoding UTF8 generated bytes string Sutf16erro = new String (Bytesdefault, "UTF16"); System.out.println (Sutf16erro);//2, decoding UTF8 bytes generated with unicode encoding string sunicodeerror = new String (Bytesdefault, "Unicode"); System.out.println (sunicodeerror);//3, decoding UTF8 generated bytes

directly allocated NIO buffer to read sensitive data from a file. After the data has been used. It can be cleared immediately, and sensitive data is not slow to exist in multiple locations, only in system memory.void ReadData () {Bytebuffer BB = bytebuffer.allocatedirect (16*1024); try (filechannel rdr = (new FileInputStream ("file")) . Getchannel ()) {while (Rdr.read (BB) > 0) {//does something with the Bufferbb.clear ();}} catch (Throwable e) {//Handle err or}}It is important to note that the

), which uses other encryption modes other than the ECB, needs to pass in an initial vector, which is equal to the block size and the AES block size is 128bit, so the length of the IV is 16 bytes and the initial vector can enhance the algorithm strength. Encryption Mode (Cipher mode) has CBC, ECB, CTR, ofb, CFB five species. The Padding method (Padding) determines the content that the last block needs to be populated, filled with pkcs5padding, pkcs7padding, nopadding three, but the JDK only prov

java.sql.PreparedStatement instead of java.sql.Statement.(6) The method prefix used to set the state of the object must be set; the method prefix used to retrieve the state of a Boolean type object must be is, and the other method prefix must be get.(7) The program should use as few numbers (or characters) as possible, define static variables to illustrate the meaning of the number (or character). When you need to assign or compare in a program, use the static variables defined earlier. Excepti

In this paper, we describe the method of Base64 encoding for utf-8 of Chinese strings by JS. Share to everyone for your reference, specific as follows: String to encode: "Select username from user" Using Java for encoding, Java programs: String sql = "Select User name from user"; String encodestr = new String (Base64.encode (Sql.getbytes ("UTF-8")); Coding