Http://developer.51cto.com/art/201511/496849.htm
The Apache Commons contains a number of open source tools for solving problems that are often encountered in programming and reducing duplication of effort. I chose some more commonly used items to do a brief introduction. The article used a lot of online ready-made things, I just did a summary of the finishing.
First, Commons beanutils
Http://jakarta.apache.org/commons/beanutils/index.html
Description: A tool set for the bean. Since beans tend to have a bunch of get and set compositions, Beanutils also makes some packaging on this basis.
Use examples: There are many features, detailed on the Web site. A more common feature is bean copy, which is the property of the copy bean. It would be used if you were developing a layered architecture, such as copying data from PO (persistent object) to Vo (Value object).
The traditional methods are as follows:
Get Teacherform teacherform teacherform= (teacherform) Form; Construct Teacher Object Teacher teacher=new Teacher (); Assigned Value Teacher.setname (Teacherform.getname ()); Teacher.setage (Teacherform.getage ()); Teacher.setgender (Teacherform.getgender ()); Teacher.setmajor (Teacherform.getmajor ()); Teacher.setdepartment (Teacherform.getdepartment ()); Persisting teacher object to database hibernatedao=; Hibernatedao.save (teacher);
With Beanutils, the code has changed dramatically, as follows:
Get Teacherform teacherform teacherform= (teacherform) Form; Construct Teacher Object Teacher teacher=new Teacher (); The assigned value beanutils.copyproperties (teacher,teacherform); Persisting teacher object to database hibernatedao=; Hibernatedao.save (teacher);
Ii. Commons CLI
Http://jakarta.apache.org/commons/cli/index.html
Description: This is a tool for processing commands. For example, the main method input string[] needs parsing. You can define the rules of the parameters in advance, and then you can invoke the CLI to resolve them.
Use examples:
create Options object options options = new options (); // add t option, option is the command parameter, false indicates that // this parameter is not required. Options.addoption ("T", false, "Display current time"); options.addoption ("C", true, "Country code"); Commandlineparser parser = new posixparser (); Commandline cmd = parser.parse ( options, args); if (cmd.hasOption ("T" ) { // print the date and time }else { // print the date } // get c option value String countrycode = cmd.getoptionvalue ("C"); if (countrycode == null ) { // print default date }else { // print date for country specified by countryCode }
Third, Commons Codec
Http://jakarta.apache.org/commons/codec/index.html
Description: This tool is used to encode and decode, including Base64,url,soundx and so on. People with this tool should be very clear about this, I will not introduce more.
Iv. Commons Collections
http://jakarta.apache.org/commons/collections/
Description: You can think of this tool as a java.util extension.
Use example: To give a simple example
Orderedmap map = new Linkedmap (); Map.put ("FIVE", "5"); Map.put ("SIX", "6"); Map.put ("SEVEN", "7");