fitler commons

Through the above diagram, you can simply clarify the relationship!Commons-logging and SLF4J are log interfaces for use by users, without providing implementations!Log4j,logback and so on is the real implementation of the log.When we invoke an interface, the factory of the interface automatically finds the appropriate implementation, returning an instance of the implementation to the service. These processes are transparent and users do not need to do

Apache Commons DbUtils User ManualApache Commons DbUtils user manual I. IntroductionDBUtils is a lightweight JDBC package. Its core feature is to encapsulate the result set on the basis of JDBC, the query result set can be directly encapsulated into a JavaBean to simplify the confusion and repetition of JDBC code.JDBC code development has many difficulties:1) the operation process is complex. The Code opera

Quartz error:Caused by: Java. Lang. nosuchmethoderror: org. Apache. commons. Collections. setutils. orderedset (ljava/util/set;) ljava/util/set;The reason is that the use of the commons-collections.jar version is too low caused by the use of 3.For those using myeclipse, if the commons-collections.jar is imported 3. * The package does not work yet. If other packag

In practice, we often encounter areas where pooling is needed, especially database connection pooling.Why do we need a pool? Because these resources are created, resources are consumed. Therefore, we use an object pool, which is pre-created with some resource objects. When we need to, we pull the object out of the pool, and when we don't need it, we return the object to the pool. This can improve the efficiency of your code's operation.Apache Commons

When the project is used similarly as follows, the system will report a null pointer exception. This error is only true for the development environment, the simulation environment, and the formal environment. import org.apache.commons.beanutils.ConvertUtils;public class T {/** * @param args * @author Ken_xu */public static void main(String[] args) {// TODO Auto-generated method stubObject obj = ConvertUtils.convert("1", null);System.out.println(obj);}} Exception in thread "Main" Java. Lang. nul

OverviewDuring the operation of the project, some operations on the system resource consumption is large, such as the establishment of database connections, the establishment of REDIS connections, and so on, we want to create multiple connection objects at one time, and in the future when we need to use the created connection directly, to improve performance. The pool technology uses pool technology to improve application service performance by initializing some of the more resource-intensive ob

Multi-file uploading using Jakarta commons FileUpload ComponentOnce wrote an article "Use Multipartfile implementation file upload", but recently in the work, I need to upload multiple files at the same time, it seems to use multipartfile can not be competent, so thought of the Jakarta Commons. Jakarta Commons is really good, there are so many open source and eas

Apache Commons NET, the processing of mail is very strong, so you can do some of their own mail work. Building a mail server is relatively troublesome, we still directly use the ready-made mail server, such as through the QQ mailbox to receive some mail.Before using this, make sure you have a mailbox and know the POP3 service agreement address for this mailbox and the user name and password for this mailbox.Using NET Package implementation Simple POP3

* Java. lang. string * Java. SQL. date * Java. SQL. time * Java. SQL. timestampNote that Java. util. date is not supported, and its subclass java. SQL. date is supported. Therefore, if the object contains time-type attributes and you want to convert them, you must use the java. SQL. date type. Otherwise, an argument mistype exception occurs during conversion.Iii. Advantages and Disadvantages:The Apache Jakarta Commons project is very useful. I have u

Org. apache. commons. beanutils is a sub-project under Apache commons. Because of tracking struts, we tracked this package in depth and found that some static tool functions provided by the beanutils class are still very useful. This toolkit is widely used in struts to operate the struts actionform object. Clonebean: copy a bean object. The reflect method is used to call getter and setter to copy bean ob

Use APACHE-commons-fileupload to write a JSP file to be uploaded You need to download the fileupload and beanutils packages. The Code is as follows. String mkdir (string path ){ String MSG = NULL;Java. Io. File dir; // Create a file objectDir = new java. Io. File (PATH );If (DIR = NULL ){MSG = "error cause: Return MSG;}If (dir. isfile ()){MSG = "error cause: Return MSG;}If (! Dir. exists ()){Boolean result = dir. mkdirs ();If (resu

The exception information is as follows: Exception in thread "Main" Java. Lang. noclassdeffounderror: ORG/Apache/WS/commons/Schema/utils/namespaceprefixlistAt org. Apache. cxf. jaxws. jaxwsclientfactorybean. At org. Apache. cxf. jaxws. jaxwsproxyfactorybean. At CN. navidog. Common. webwervice. Client. rankclient. At CN. navidog. Front. Users. testwebservice. Main (testwebservice. Java: 10)Caused by: Java. Lang. classnotfoundexception: org. Apache. ws.

In Apache Commons-lang (more than 2.3), we have provided a handy tool class for escaping, mainly to prevent SQL injection, the function of XSS injection attack. In total, the following methods are available:1.ESCAPESQL provides SQL transfer capabilities to prevent SQL injection attacks, such as typical universal password attacks ' or 1=1 ' StringBuffer sql = new StringBuffer ("Select Key_sn,remark,create_date from Tb_selogon_key where 1=1");

Commons-fileupload New API use, old use, need temp directory, new API directly use stream way as follows checkthatwehaveafileuploadrequestbooleanismultipart =servletfileupload.ismultipartcontent (Request);//createanewfile Uploadhandlerservletfileuploadupload=newservletfileupload ();//Parse Therequestfileitemiteratoriter=upload.getitemiterator (Request);while ( Iter.hasnext ()) {fileitemstreamitem=iter.next (); stringname=item.getfieldname (); inputstr

Recent projects need to implement FTP upload, download function, using the Apache Commons Net API. The code is done quickly, but because the API usage scenario is not very familiar, take a few detours, and take a moment to summarize. A)Active Passive Mode selection:FTPa detailed introduction to active and passive modes is available for reference (http://blog.csdn.net/huanggang028/article/details/41248663). The idea is that the active mode is the clien

Org. apache. commons. beanutils. BeanMap simple example, commonsbeanutils1. org. apache. commons. beanutils. BeanMap; a java bean can be called through the map api, Several supported Operation interfaces: Object get (Object key) Object put (Object key, Object value) Void putAll (Map t) Set entrySet () Collection values () Boolean containsKey (Object key) .... For example: // Concatenate the student

Because the FTP operation is needed in the recent work, and there is no existing FTP code on hand. Went online to find a bit, found that everyone using Apache Commons-net Library in the ftpclient.However, the feeling is not very convenient to use. And found a lot of packages on the Internet. I think it's not very useful. So I wrote one of my own. Most of the examples on the web are directly manipulating files, and what I need more is to read the memor