Apache Commons包含了很多開(kāi)源的工具,用于解決平時(shí)編程經(jīng)常會(huì)遇到的問(wèn)題,減少重復(fù)勞動(dòng)。下面是我這幾年做開(kāi)發(fā)過(guò)程中自己用過(guò)的工具類(lèi)做簡(jiǎn)單介紹。
組件 | 功能介紹 |
BeanUtils | 提供了對(duì)于JavaBean進(jìn)行各種操作,克隆對(duì)象,屬性等等. |
Betwixt | XML與Java對(duì)象之間相互轉(zhuǎn)換. |
Codec | 處理常用的編碼方法的工具類(lèi)包 例如DES、SHA1、MD5、Base64等. |
Collections | java集合框架操作. |
Compress | java提供文件打包 壓縮類(lèi)庫(kù). |
Configuration | 一個(gè)java應(yīng)用程序的配置管理類(lèi)庫(kù). |
DBCP | 提供數(shù)據(jù)庫(kù)連接池服務(wù). |
DbUtils | 提供對(duì)jdbc 的操作封裝來(lái)簡(jiǎn)化數(shù)據(jù)查詢和記錄讀取操作. |
java發(fā)送郵件 對(duì)javamail的封裝. | |
FileUpload | 提供文件上傳功能. |
HttpClien | 提供HTTP客戶端與服務(wù)器的各種通訊操作. 現(xiàn)在已改成HttpComponents |
IO | io工具的封裝. |
Lang | Java基本對(duì)象方法的工具類(lèi)包 如:StringUtils,ArrayUtils等等. |
Logging | 提供的是一個(gè)Java 的日志接口. |
Validator | 提供了客戶端和服務(wù)器端的數(shù)據(jù)驗(yàn)證框架. |
1、BeanUtils 提供了對(duì)于JavaBean進(jìn)行各種操作, 比如對(duì)象,屬性復(fù)制等等。
//1、 克隆對(duì)象 // 新創(chuàng)建一個(gè)普通Java Bean,用來(lái)作為被克隆的對(duì)象 public class Person { private String name = ""; private String email = ""; private int age; //省略 set,get方法}// 再創(chuàng)建一個(gè)Test類(lèi),其中在main方法中代碼如下: import java.lang.reflect.InvocationTargetException;import java.util.HashMap;import java.util.Map;import org.apache.commons.beanutils.BeanUtils;import org.apache.commons.beanutils.ConvertUtils;public class Test { /** * @param args */ public static void main(String[] args) { Person person = new Person(); person.setName("tom"); person.setAge(21); try { //克隆 Person person2 = (Person)BeanUtils.cloneBean(person); System.out.println(person2.getName()+">>"+person2.getAge()); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InstantiationException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } catch (NoSuchMethodException e) { e.printStackTrace(); } }}// 原理也是通過(guò)Java的反射機(jī)制來(lái)做的。 // 2、 將一個(gè)Map對(duì)象轉(zhuǎn)化為一個(gè)Bean // 這個(gè)Map對(duì)象的key必須與Bean的屬性相對(duì)應(yīng)。 Map map = new HashMap();map.put("name","tom");map.put("email","tom@");map.put("age","21");//將map轉(zhuǎn)化為一個(gè)Person對(duì)象 Person person = new Person();BeanUtils.populate(person,map);// 通過(guò)上面的一行代碼,此時(shí)person的屬性就已經(jīng)具有了上面所賦的值了。 // 將一個(gè)Bean轉(zhuǎn)化為一個(gè)Map對(duì)象了,如下: Map map = BeanUtils.describe(person)
2、Betwixt XML與Java對(duì)象之間相互轉(zhuǎn)換。
//1、 將JavaBean轉(zhuǎn)為XML內(nèi)容 // 新創(chuàng)建一個(gè)Person類(lèi) public class Person{ private String name; private int age; /** Need to allow bean to be created via reflection */ public PersonBean() { } public PersonBean(String name, int age) { this.name = name; this.age = age; } //省略set, get方法 public String toString() { return "PersonBean[name='" + name + "',age='" + age + "']"; }}//再創(chuàng)建一個(gè)WriteApp類(lèi): import java.io.StringWriter;import org.apache.commons.betwixt.io.BeanWriter;public class WriteApp { /** * 創(chuàng)建一個(gè)例子Bean,并將它轉(zhuǎn)化為XML. */ public static final void main(String [] args) throws Exception { // 先創(chuàng)建一個(gè)StringWriter,我們將把它寫(xiě)入為一個(gè)字符串 StringWriter outputWriter = new StringWriter(); // Betwixt在這里僅僅是將Bean寫(xiě)入為一個(gè)片斷 // 所以如果要想完整的XML內(nèi)容,我們應(yīng)該寫(xiě)入頭格式 outputWriter.write(“<?xml version='1.0′ encoding='UTF-8′ ?>/n”); // 創(chuàng)建一個(gè)BeanWriter,其將寫(xiě)入到我們預(yù)備的stream中 BeanWriter beanWriter = new BeanWriter(outputWriter); // 配置betwixt // 更多詳情請(qǐng)參考java docs 或最新的文檔 beanWriter.getXMLIntrospector().getConfiguration().setAttributesForPrimitives(false); beanWriter.getBindingConfiguration().setMapIDs(false); beanWriter.enablePrettyPrint(); // 如果這個(gè)地方不傳入XML的根節(jié)點(diǎn)名,Betwixt將自己猜測(cè)是什么 // 但是讓我們將例子Bean名作為根節(jié)點(diǎn)吧 beanWriter.write(“person”, new PersonBean(“John Smith”, 21)); //輸出結(jié)果 System.out.println(outputWriter.toString()); // Betwixt寫(xiě)的是片斷而不是一個(gè)文檔,所以不要自動(dòng)的關(guān)閉掉writers或者streams, //但這里僅僅是一個(gè)例子,不會(huì)做更多事情,所以可以關(guān)掉 outputWriter.close(); }}//2、 將XML轉(zhuǎn)化為JavaBean import java.io.StringReader;import org.apache.commons.betwixt.io.BeanReader;public class ReadApp { public static final void main(String args[]) throws Exception{ // 先創(chuàng)建一個(gè)XML,由于這里僅是作為例子,所以我們硬編碼了一段XML內(nèi)容 StringReader xmlReader = new StringReader( "<?xml version='1.0′ encoding='UTF-8′ ?> <person><age>25</age><name>James Smith</name></person>"); //創(chuàng)建BeanReader BeanReader beanReader = new BeanReader(); //配置reader beanReader.getXMLIntrospector().getConfiguration().setAttributesForPrimitives(false); beanReader.getBindingConfiguration().setMapIDs(false); //注冊(cè)beans,以便betwixt知道XML將要被轉(zhuǎn)化為一個(gè)什么Bean beanReader.registerBeanClass("person", PersonBean.class); //現(xiàn)在我們對(duì)XML進(jìn)行解析 PersonBean person = (PersonBean) beanReader.parse(xmlReader); //輸出結(jié)果 System.out.println(person); }}
3、Codec 提供了一些公共的編解碼實(shí)現(xiàn),比如Base64, Hex, MD5,Phonetic and URLs等等。
//Base64編解碼 private static String encodeTest(String str){ Base64 base64 = new Base64(); try { str = base64.encodeToString(str.getBytes("UTF-8")); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } System.out.println("Base64 編碼后:"+str); return str;}private static void decodeTest(String str){ Base64 base64 = new Base64(); //str = Arrays.toString(Base64.decodeBase64(str)); str = new String(Base64.decodeBase64(str)); System.out.println("Base64 解碼后:"+str);}
4、Collections 對(duì)java.util的擴(kuò)展封裝,處理數(shù)據(jù)還是挺靈活的。
org.apache.commons.collections – Commons Collections自定義的一組公用的接口和工具類(lèi)
org.apache.commons.collections.bag – 實(shí)現(xiàn)Bag接口的一組類(lèi)
org.apache.commons.collections.bidimap – 實(shí)現(xiàn)BidiMap系列接口的一組類(lèi)
org.apache.commons.collections.buffer – 實(shí)現(xiàn)Buffer接口的一組類(lèi)
org.apache.commons.collections.collection – 實(shí)現(xiàn)java.util.Collection接口的一組類(lèi)
org.apache.commons.collections.comparators – 實(shí)現(xiàn)java.util.Comparator接口的一組類(lèi)
org.apache.commons.collections.functors – Commons Collections自定義的一組功能類(lèi)
org.apache.commons.collections.iterators – 實(shí)現(xiàn)java.util.Iterator接口的一組類(lèi)
org.apache.commons.collections.keyvalue – 實(shí)現(xiàn)集合和鍵/值映射相關(guān)的一組類(lèi)
org.apache.commons.collections.list – 實(shí)現(xiàn)java.util.List接口的一組類(lèi)
org.apache.commons.collections.map – 實(shí)現(xiàn)Map系列接口的一組類(lèi)
org.apache.commons.collections.set – 實(shí)現(xiàn)Set系列接口的一組類(lèi)
/** * 得到集合里按順序存放的key之后的某一Key */OrderedMap map = new LinkedMap();map.put("FIVE", "5");map.put("SIX", "6");map.put("SEVEN", "7");map.firstKey();// returns "FIVE" map.nextKey("FIVE");// returns "SIX" map.nextKey("SIX");// returns "SEVEN" /** * 通過(guò)key得到value * 通過(guò)value得到key * 將map里的key和value對(duì)調(diào) */BidiMap bidi = new TreeBidiMap();bidi.put("SIX", "6");bidi.get("SIX");// returns "6" bidi.getKey("6");// returns "SIX" // bidi.removeValue("6"); // removes the mapping BidiMap inverse = bidi.inverseBidiMap();// returns a map with keys and values swapped System.out.println(inverse);/** * 得到兩個(gè)集合中相同的元素 */List<String> list1 = new ArrayList<String>();list1.add("1");list1.add("2");list1.add("3");List<String> list2 = new ArrayList<String>();list2.add("2");list2.add("3");list2.add("5");Collection c = CollectionUtils.retainAll(list1, list2);System.out.println(c);
5、Compress commons compress中的打包、壓縮類(lèi)庫(kù)。
//創(chuàng)建壓縮對(duì)象 ZipArchiveEntry entry = new ZipArchiveEntry("CompressTest");//要壓縮的文件 File f=new File("e://test.pdf");FileInputStream fis=new FileInputStream(f);//輸出的對(duì)象 壓縮的文件 ZipArchiveOutputStream zipOutput=new ZipArchiveOutputStream(new File("e://test.zip"));zipOutput.putArchiveEntry(entry);int i=0,j;while((j=fis.read()) != -1) { zipOutput.write(j); i++; System.out.println(i);}zipOutput.closeArchiveEntry();zipOutput.close();fis.close();
6、Configuration 用來(lái)幫助處理配置文件的,支持很多種存儲(chǔ)方式。
1. Properties files
2. XML documents
3. Property list files (.plist)
4. JNDI
5. JDBC Datasource
6. System properties
7. Applet parameters
8. Servlet parameters
//舉一個(gè)Properties的簡(jiǎn)單例子 # usergui.properties colors.background = #FFFFFF colors.foreground = #000080 window.width = 500 window.height = 300 PropertiesConfiguration config = new PropertiesConfiguration("usergui.properties");config.setProperty("colors.background", "#000000); config.save(); config.save("usergui.backup.properties);//save a copy Integer integer = config.getInteger("window.width");
7、DBCP (Database Connection Pool)是一個(gè)依賴(lài)Jakarta commons-pool對(duì)象池機(jī)制的數(shù)據(jù)庫(kù)連接池,Tomcat的數(shù)據(jù)源使用的就是DBCP。
import javax.sql.DataSource;import java.sql.Connection;import java.sql.Statement;import java.sql.ResultSet;import java.sql.SQLException;import org.apache.commons.pool.ObjectPool;import org.apache.commons.pool.impl.GenericObjectPool;import org.apache.commons.dbcp.ConnectionFactory;import org.apache.commons.dbcp.PoolingDataSource;import org.apache.commons.dbcp.PoolableConnectionFactory;import org.apache.commons.dbcp.DriverManagerConnectionFactory;//官方示例 public class PoolingDataSources { public static void main(String[] args) { System.out.println("加載jdbc驅(qū)動(dòng)"); try { Class.forName("oracle.jdbc.driver.OracleDriver"); } catch (ClassNotFoundException e) { e.printStackTrace(); } System.out.println("Done."); // System.out.println("設(shè)置數(shù)據(jù)源"); DataSource dataSource = setupDataSource("jdbc:oracle:thin:@localhost:1521:test"); System.out.println("Done."); // Connection conn = null; Statement stmt = null; ResultSet rset = null; try { System.out.println("Creating connection."); conn = dataSource.getConnection(); System.out.println("Creating statement."); stmt = conn.createStatement(); System.out.println("Executing statement."); rset = stmt.executeQuery("select * from person"); System.out.println("Results:"); int numcols = rset.getMetaData().getColumnCount(); while(rset.next()) { for (int i=0;i<=numcols;i++) { System.out.print("/t" + rset.getString(i)); } System.out.println(""); } } catch(SQLException e) { e.printStackTrace(); } finally { try { if (rset != null) rset.close(); } catch(Exception e) { } try { if (stmt != null) stmt.close(); } catch(Exception e) { } try { if (conn != null) conn.close(); } catch(Exception e) { } } } public static DataSource setupDataSource(String connectURI) { //設(shè)置連接地址 ConnectionFactory connectionFactory = new DriverManagerConnectionFactory( connectURI, null); // 創(chuàng)建連接工廠 PoolableConnectionFactory poolableConnectionFactory = new PoolableConnectionFactory( connectionFactory); //獲取GenericObjectPool 連接的實(shí)例 ObjectPool connectionPool = new GenericObjectPool( poolableConnectionFactory); // 創(chuàng)建 PoolingDriver PoolingDataSource dataSource = new PoolingDataSource(connectionPool); return dataSource; }}
8、DbUtilsApache組織提供的一個(gè)資源JDBC工具類(lèi)庫(kù),它是對(duì)JDBC的簡(jiǎn)單封裝,對(duì)傳統(tǒng)操作數(shù)據(jù)庫(kù)的類(lèi)進(jìn)行二次封裝,可以把結(jié)果集轉(zhuǎn)化成List。,同時(shí)也不影響程序的性能。
DbUtils類(lèi):?jiǎn)?dòng)類(lèi)
ResultSetHandler接口:轉(zhuǎn)換類(lèi)型接口
MapListHandler類(lèi):實(shí)現(xiàn)類(lèi),把記錄轉(zhuǎn)化成List
BeanListHandler類(lèi):實(shí)現(xiàn)類(lèi),把記錄轉(zhuǎn)化成List,使記錄為JavaBean類(lèi)型的對(duì)象
QreryRunner類(lèi):執(zhí)行SQL語(yǔ)句的類(lèi)
import org.apache.commons.dbutils.DbUtils;import org.apache.commons.dbutils.QueryRunner;import org.apache.commons.dbutils.handlers.BeanListHandler;import java.sql.Connection;import java.sql.DriverManager;import java.sql.SQLException;import java.util.List;//轉(zhuǎn)換成list public class BeanLists { public static void main(String[] args) { Connection conn = null; String url = "jdbc:mysql://localhost:3306/ptest"; String jdbcDriver = "com.mysql.jdbc.Driver"; String user = "root"; String password = "ptest"; DbUtils.loadDriver(jdbcDriver); try { conn = DriverManager.getConnection(url, user, password); QueryRunner qr = new QueryRunner(); List results = (List) qr.query(conn, "select id,name from person", new BeanListHandler(Person.class)); for (int i = 0; i < results.size(); i++) { Person p = (Person) results.get(i); System.out.println("id:" + p.getId() + ",name:" + p.getName()); } } catch (SQLException e) { e.printStackTrace(); } finally { DbUtils.closeQuietly(conn); } }}public class Person{ private Integer id; private String name; //省略set, get方法}import org.apache.commons.dbutils.DbUtils;import org.apache.commons.dbutils.QueryRunner;import org.apache.commons.dbutils.handlers.MapListHandler;import java.sql.Connection;import java.sql.DriverManager;import java.sql.SQLException;import java.util.List;import java.util.Map;//轉(zhuǎn)換成map public class MapLists { public static void main(String[] args) { Connection conn = null; String url = "jdbc:mysql://localhost:3306/ptest"; String jdbcDriver = "com.mysql.jdbc.Driver"; String user = "root"; String password = "ptest"; DbUtils.loadDriver(jdbcDriver); try { conn = DriverManager.getConnection(url, user, password); QueryRunner qr = new QueryRunner(); List results = (List) qr.query(conn, "select id,name from person", new MapListHandler()); for (int i = 0; i < results.size(); i++) { Map map = (Map) results.get(i); System.out.println("id:" + map.get("id") + ",name:" + map.get("name")); } } catch (SQLException e) { e.printStackTrace(); } finally { DbUtils.closeQuietly(conn); } }}
9、Email 提供的一個(gè)開(kāi)源的API,是對(duì)javamail的封裝。
//用commons email發(fā)送郵件 public static void main(String args[]){ Email email = new SimpleEmail(); email.setHostName("smtp.googlemail.com"); email.setSmtpPort(465); email.setAuthenticator(new DefaultAuthenticator("username", "password")); email.setSSLOnConnect(true); email.setFrom("user@gmail.com"); email.setSubject("TestMail"); email.setMsg("This is a test mail ... :-)"); email.addTo("foo@bar.com"); email.send();}
10、FileUpload java web文件上傳功能。
//官方示例: //* 檢查請(qǐng)求是否含有上傳文件 // Check that we have a file upload request Boolean isMultipart = ServletFileUpload.isMultipartContent(request);//現(xiàn)在我們得到了items的列表 //如果你的應(yīng)用近于最簡(jiǎn)單的情況,上面的處理就夠了。但我們有時(shí)候還是需要更多的控制。 //下面提供了幾種控制選擇: // Create a factory for disk-based file items DiskFileItemFactory factory = new DiskFileItemFactory();// Set factory constraints factory.setSizeThreshold(yourMaxMemorySize);factory.setRepository(yourTempDirectory);// Create a new file upload handler ServletFileUpload upload = new ServletFileUpload(factory);// 設(shè)置最大上傳大小 upload.setSizeMax(yourMaxRequestSize);// 解析所有請(qǐng)求 List /* FileItem */items = upload.parseRequest(request);// Create a factory for disk-based file items DiskFileItemFactory factory = new DiskFileItemFactory( yourMaxMemorySize, yourTempDirectory);//一旦解析完成,你需要進(jìn)一步處理item的列表。 // Process the uploaded items Iterator iter = items.iterator();while (iter.hasNext()) { FileItem item = (FileItem) iter.next(); if (item.isFormField()) { processFormField(item); } else { processUploadedFile(item); }}//區(qū)分?jǐn)?shù)據(jù)是否為簡(jiǎn)單的表單數(shù)據(jù),如果是簡(jiǎn)單的數(shù)據(jù): // processFormField if (item.isFormField()) { String name = item.getFieldName(); String value = item.getString(); //...省略步驟}//如果是提交的文件: // processUploadedFile if (!item.isFormField()) { String fieldName = item.getFieldName(); String fileName = item.getName(); String contentType = item.getContentType(); Boolean isInMemory = item.isInMemory(); long sizeInBytes = item.getSize(); //...省略步驟}//對(duì)于這些item,我們通常要把它們寫(xiě)入文件,或轉(zhuǎn)為一個(gè)流 // Process a file upload if (writeToFile) { File uploadedFile = new File(...); item.write(uploadedFile);} else { InputStream uploadedStream = item.getInputStream(); //...省略步驟 uploadedStream.close();}//或轉(zhuǎn)為字節(jié)數(shù)組保存在內(nèi)存中: // Process a file upload in memory byte[] data = item.get();//...省略步驟 //如果這個(gè)文件真的很大,你可能會(huì)希望向用戶報(bào)告到底傳了多少到服務(wù)端,讓用戶了解上傳的過(guò)程 //Create a progress listener ProgressListener progressListener = new ProgressListener(){ public void update(long pBytesRead, long pContentLength, int pItems) { System.out.println("We are currently reading item " + pItems); if (pContentLength == -1) { System.out.println("So far, " + pBytesRead + " bytes have been read."); } else { System.out.println("So far, " + pBytesRead + " of " + pContentLength + " bytes have been read."); } }};upload.setProgressListener(progressListener);
11、HttpClien 基于HttpCore實(shí) 現(xiàn)的一個(gè)HTTP/1.1兼容的HTTP客戶端,它提供了一系列可重用的客戶端身份驗(yàn)證、HTTP狀態(tài)保持、HTTP連接管理module。
//GET方法 import java.io.IOException;import org.apache.commons.httpclient.*;import org.apache.commons.httpclient.methods.GetMethod;import org.apache.commons.httpclient.params.HttpMethodParams;public class GetSample{ public static void main(String[] args) { // 構(gòu)造HttpClient的實(shí)例 HttpClient httpClient = new HttpClient(); // 創(chuàng)建GET方法的實(shí)例 GetMethod getMethod = new GetMethod("http://www.ibm.com"); // 使用系統(tǒng)提供的默認(rèn)的恢復(fù)策略 getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler()); try { // 執(zhí)行g(shù)etMethod int statusCode = httpClient.executeMethod(getMethod); if (statusCode != HttpStatus.SC_OK) { System.err.println("Method failed: " + getMethod.getStatusLine()); } // 讀取內(nèi)容 byte[] responseBody = getMethod.getResponseBody(); // 處理內(nèi)容 System.out.println(new String(responseBody)); } catch (HttpException e) { // 發(fā)生致命的異常,可能是協(xié)議不對(duì)或者返回的內(nèi)容有問(wèn)題 System.out.println("Please check your provided http address!"); e.printStackTrace(); } catch (IOException e) { // 發(fā)生網(wǎng)絡(luò)異常 e.printStackTrace(); } finally { // 釋放連接 getMethod.releaseConnection(); } }}//POST方法 import java.io.IOException;import org.apache.commons.httpclient.*;import org.apache.commons.httpclient.methods.PostMethod;import org.apache.commons.httpclient.params.HttpMethodParams;public class PostSample{ public static void main(String[] args) { // 構(gòu)造HttpClient的實(shí)例 HttpClient httpClient = new HttpClient(); // 創(chuàng)建POST方法的實(shí)例 String url = "http://www.oracle.com/"; PostMethod postMethod = new PostMethod(url); // 填入各個(gè)表單域的值 NameValuePair[] data = { new NameValuePair("id", "youUserName"), new NameValuePair("passwd", "yourPwd") } ; // 將表單的值放入postMethod中 postMethod.setRequestBody(data); // 執(zhí)行postMethod int statusCode = httpClient.executeMethod(postMethod); // HttpClient對(duì)于要求接受后繼服務(wù)的請(qǐng)求,象POST和PUT等不能自動(dòng)處理轉(zhuǎn)發(fā) // 301或者302 if (statusCode == HttpStatus.SC_MOVED_PERMANENTLY || statusCode == HttpStatus.SC_MOVED_TEMPORARILY) { // 從頭中取出轉(zhuǎn)向的地址 Header locationHeader = postMethod.getResponseHeader("location"); String location = null; if (locationHeader != null) { location = locationHeader.getValue(); System.out.println("The page was redirected to:" + location); } else { System.err.println("Location field value is null."); } return; }}}
12、IO 對(duì)java.io的擴(kuò)展 操作文件非常方便。
//1.讀取Stream //標(biāo)準(zhǔn)代碼: InputStream in = new URL( "http://jakarta.apache.org" ).openStream();try { InputStreamReader inR = new InputStreamReader( in ); BufferedReader buf = new BufferedReader( inR ); String line; while ( ( line = buf.readLine() ) != null ) { System.out.println( line ); }}finally { in.close();}//使用IOUtils InputStream in = new URL( "http://jakarta.apache.org" ).openStream();try { System.out.println( IOUtils.toString( in ) );}finally { IOUtils.closeQuietly(in);}//2.讀取文件 File file = new File("/commons/io/project.properties");List lines = FileUtils.readLines(file, "UTF-8");//3.察看剩余空間 long freeSpace = FileSystemUtils.freeSpace("C:/");
13、Lang 主要是一些公共的工具集合,比如對(duì)字符、數(shù)組的操作等等。
// 1 合并兩個(gè)數(shù)組: org.apache.commons.lang. ArrayUtils // 有時(shí)我們需要將兩個(gè)數(shù)組合并為一個(gè)數(shù)組,用ArrayUtils就非常方便,示例如下: private static void testArr() { String[] s1 = new String[] { "1", "2", "3" }; String[] s2 = new String[] { "a", "b", "c" }; String[] s = (String[]) ArrayUtils.addAll(s1, s2); for (int i = 0; i < s.length; i++) { System.out.println(s[i]); } String str = ArrayUtils.toString(s); str = str.substring(1, str.length() - 1); System.out.println(str + ">>" + str.length());}//2 截取從from開(kāi)始字符串 StringUtils.substringAfter("SELECT * FROM PERSON ", "from");//3 判斷該字符串是不是為數(shù)字(0~9)組成,如果是,返回true 但該方法不識(shí)別有小數(shù)點(diǎn)和 請(qǐng)注意 StringUtils.isNumeric("454534");//返回true //4.取得類(lèi)名 System.out.println(ClassUtils.getShortClassName(Test.class));//取得其包名 System.out.println(ClassUtils.getPackageName(Test.class));//5.NumberUtils System.out.println(NumberUtils.stringToint("6"));//6.五位的隨機(jī)字母和數(shù)字 System.out.println(RandomStringUtils.randomAlphanumeric(5));//7.StringEscapeUtils System.out.println(StringEscapeUtils.escapeHtml("<html>"));//輸出結(jié)果為<html> System.out.println(StringEscapeUtils.escapeJava("String"));//8.StringUtils,判斷是否是空格字符 System.out.println(StringUtils.isBlank(" "));//將數(shù)組中的內(nèi)容以,分隔 System.out.println(StringUtils.join(test,","));//在右邊加下字符,使之總長(zhǎng)度為6 System.out.println(StringUtils.rightPad("abc", 6, 'T'));//首字母大寫(xiě) System.out.println(StringUtils.capitalize("abc"));//Deletes all whitespaces from a String 刪除所有空格 System.out.println( StringUtils.deleteWhitespace(" ab c "));//判斷是否包含這個(gè)字符 System.out.println( StringUtils.contains("abc", "ba"));//表示左邊兩個(gè)字符 System.out.println( StringUtils.left("abc", 2));System.out.println(NumberUtils.stringToint("33"));
14、Logging 提供的是一個(gè)Java 的日志接口,同時(shí)兼顧輕量級(jí)和不依賴(lài)于具體的日志實(shí)現(xiàn)工具。
import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;public class CommonLogTest { private static Log log = LogFactory.getLog(CommonLogTest.class); //日志打印 public static void main(String[] args) { log.error("ERROR"); log.debug("DEBUG"); log.warn("WARN"); log.info("INFO"); log.trace("TRACE"); System.out.println(log.getClass()); }}
15、Validator 通用驗(yàn)證系統(tǒng),該組件提供了客戶端和服務(wù)器端的數(shù)據(jù)驗(yàn)證框架。
驗(yàn)證日期
// 獲取日期驗(yàn)證 DateValidator validator = DateValidator.getInstance();// 驗(yàn)證/轉(zhuǎn)換日期 Date fooDate = validator.validate(fooString, "dd/MM/yyyy");if (fooDate == null) { // 錯(cuò)誤 不是日期 return;}
表達(dá)式驗(yàn)證
// 設(shè)置參數(shù) Boolean caseSensitive = false;String regex1 = "^([A-Z]*)(?://-)([A-Z]*)*$" String regex2 = "^([A-Z]*)$";String[] regexs = new String[] {regex1, regex1};// 創(chuàng)建驗(yàn)證 RegexValidator validator = new RegexValidator(regexs, caseSensitive);// 驗(yàn)證返回boolean Boolean valid = validator.isValid("abc-def");// 驗(yàn)證返回字符串 String result = validator.validate("abc-def");// 驗(yàn)證返回?cái)?shù)組 String[] groups = validator.match("abc-def");
配置文件中使用驗(yàn)證
<form-validation> <global> <validator name="required" classname="org.apache.commons.validator.TestValidator" method="validateRequired" methodParams="java.lang.Object, org.apache.commons.validator.Field"/> </global> <formset> </formset> </form-validation> 添加姓名驗(yàn)證. <form-validation> <global> <validator name="required" classname="org.apache.commons.validator.TestValidator" method="validateRequired" methodParams="java.lang.Object, org.apache.commons.validator.Field"/> </global> <formset> <form name="nameForm"> <field property="firstName" depends="required"> <arg0 key="nameForm.firstname.displayname"/> </field> <field property="lastName" depends="required"> <arg0 key="nameForm.lastname.displayname"/> </field> </form> </formset> </form-validation>
驗(yàn)證類(lèi)
Excerpts from org.apache.commons.validator.RequiredNameTest //加載驗(yàn)證配置文件 InputStream in = this.getClass().getResourceAsStream("validator-name-required.xml");ValidatorResources resources = new ValidatorResources(in);//這個(gè)是自己創(chuàng)建的bean 我這里省略了 Name name = new Name();Validator validator = new Validator(resources, "nameForm");//設(shè)置參數(shù) validator.setParameter(Validator.BEAN_PARAM, name);Map results = null;//驗(yàn)證 results = validator.validate();if (results.get("firstName") == null) { //驗(yàn)證成功} else { //有錯(cuò)誤 int errors = ((Integer)results.get("firstName")).intValue();}
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