Apache Commons 工具类介绍及简单使用

1、BeanUtils

提供了对于JavaBean进行各种操作， 比如对象,属性复制等等。

//1、 克隆对象 
// 新创建一个普通Java Bean，用来作为被克隆的对象 
 public class Person { 
 private String name = ""; 
 private String email = ""; 
 private int age; 
 //省略 set,get方法 
 } 
// 再创建一个Test类，其中在main方法中代码如下：
 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(); 
 } 
 } 
 } 
// 原理也是通过Java的反射机制来做的。
// 2、 将一个Map对象转化为一个Bean 
// 这个Map对象的key必须与Bean的属性相对应。
 Map map = new HashMap(); 
 map.put("name","tom"); 
 map.put("email","tom@"); 
 map.put("age","21"); 
 //将map转化为一个Person对象 
 Person person = new Person(); 
 BeanUtils.populate(person,map); 
// 通过上面的一行代码，此时person的属性就已经具有了上面所赋的值了。
// 将一个Bean转化为一个Map对象了，如下：
 Map map = BeanUtils.describe(person)

2.Betwixt

XML与Java对象之间相互转换。

//1、 将JavaBean转为XML内容 
// 新创建一个Person类 
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 + "']"; 
 } 
} 
//再创建一个WriteApp类：
import java.io.StringWriter; 
import org.apache.commons.betwixt.io.BeanWriter; 
public class WriteApp { 
/** 
* 创建一个例子Bean，并将它转化为XML. 
*/ 
public static final void main(String [] args) throws Exception { 
 // 先创建一个StringWriter，我们将把它写入为一个字符串 
 StringWriter outputWriter = new StringWriter(); 
 // Betwixt在这里仅仅是将Bean写入为一个片断 
 // 所以如果要想完整的XML内容，我们应该写入头格式 
 outputWriter.write(“<?xml version=’1.0′ encoding=’UTF-8′ ?>\n”); 
 // 创建一个BeanWriter，其将写入到我们预备的stream中 
 BeanWriter beanWriter = new BeanWriter(outputWriter); 
 // 配置betwixt 
 // 更多详情请参考java docs 或最新的文档 
 beanWriter.getXMLIntrospector().getConfiguration().setAttributesForPrimitives(false); 
 beanWriter.getBindingConfiguration().setMapIDs(false); 
 beanWriter.enablePrettyPrint(); 
 // 如果这个地方不传入XML的根节点名，Betwixt将自己猜测是什么 
 // 但是让我们将例子Bean名作为根节点吧 
 beanWriter.write(“person”, new PersonBean(“John Smith”, 21)); 
 //输出结果 
 System.out.println(outputWriter.toString()); 
 // Betwixt写的是片断而不是一个文档，所以不要自动的关闭掉writers或者streams， 
 //但这里仅仅是一个例子，不会做更多事情，所以可以关掉 
 outputWriter.close(); 
 } 
} 
//2、 将XML转化为JavaBean 
import java.io.StringReader; 
import org.apache.commons.betwixt.io.BeanReader; 
public class ReadApp { 
public static final void main(String args[]) throws Exception{ 
 // 先创建一个XML，由于这里仅是作为例子，所以我们硬编码了一段XML内容 
 StringReader xmlReader = new StringReader( 
 "<?xml version=’1.0′ encoding=’UTF-8′ ?> <person><age>25</age><name>James Smith</name></person>"); 
 //创建BeanReader 
 BeanReader beanReader = new BeanReader(); 
 //配置reader 
 beanReader.getXMLIntrospector().getConfiguration().setAttributesForPrimitives(false); 
 beanReader.getBindingConfiguration().setMapIDs(false); 
 //注册beans，以便betwixt知道XML将要被转化为一个什么Bean 
 beanReader.registerBeanClass("person", PersonBean.class); 
 //现在我们对XML进行解析 
 PersonBean person = (PersonBean) beanReader.parse(xmlReader); 
 //输出结果 
 System.out.println(person); 
 } 
}

3.Codec

提供了一些公共的编解码实现，比如Base64, Hex, MD5,Phonetic and URLs等等。

//Base64编解码 
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 编码后："+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 解码后："+str); 
}

4.Collections

对java.util的扩展封装，处理数据还是挺灵活的。

org.apache.commons.collections – Commons Collections自定义的一组公用的接口和工具类

org.apache.commons.collections.bag – 实现Bag接口的一组类

org.apache.commons.collections.bidimap – 实现BidiMap系列接口的一组类

org.apache.commons.collections.buffer – 实现Buffer接口的一组类

org.apache.commons.collections.collection – 实现java.util.Collection接口的一组类

org.apache.commons.collections.comparators – 实现java.util.Comparator接口的一组类

org.apache.commons.collections.functors – Commons Collections自定义的一组功能类

org.apache.commons.collections.iterators – 实现java.util.Iterator接口的一组类

org.apache.commons.collections.keyvalue – 实现集合和键/值映射相关的一组类

org.apache.commons.collections.list – 实现java.util.List接口的一组类

org.apache.commons.collections.map – 实现Map系列接口的一组类

org.apache.commons.collections.set – 实现Set系列接口的一组类

/** 
* 得到集合里按顺序存放的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" 
/** 
* 通过key得到value 
* 通过value得到key 
* 将map里的key和value对调 
*/ 
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); 
/** 
 * 得到两个集合中相同的元素 
 */ 
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、压缩类库。

//创建压缩对象 
ZipArchiveEntry entry = new ZipArchiveEntry("CompressTest"); 
//要压缩的文件 
File f=new File("e:\\test.pdf"); 
FileInputStream fis=new FileInputStream(f); 
//输出的对象 压缩的文件 
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

用来帮助处理配置文件的，支持很多种存储方式。

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

//举一个Properties的简单例子 
# 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)是一个依赖Jakarta commons-pool对象池机制的数据库连接池,Tomcat的数据源使用的就是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("加载jdbc驱动"); 
 try { 
 Class.forName("oracle.jdbc.driver.OracleDriver"); 
 } catch (ClassNotFoundException e) { 
 e.printStackTrace(); 
 } 
 System.out.println("Done."); 
 // 
 System.out.println("设置数据源"); 
 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) { 
 //设置连接地址 
 ConnectionFactory connectionFactory = new DriverManagerConnectionFactory( 
 connectURI, null); 
 // 创建连接工厂 
 PoolableConnectionFactory poolableConnectionFactory = new PoolableConnectionFactory( 
 connectionFactory); 
 //获取GenericObjectPool 连接的实例 
 ObjectPool connectionPool = new GenericObjectPool( 
 poolableConnectionFactory); 
 // 创建 PoolingDriver 
 PoolingDataSource dataSource = new PoolingDataSource(connectionPool); 
 return dataSource; 
 } 
}

8.DbUtils

Apache组织提供的一个资源JDBC工具类库，它是对JDBC的简单封装，对传统操作数据库的类进行二次封装，可以把结果集转化成List。，同时也不影响程序的性能。

DbUtils类：启动类

ResultSetHandler接口：转换类型接口

MapListHandler类：实现类，把记录转化成List

BeanListHandler类：实现类，把记录转化成List，使记录为JavaBean类型的对象

Qrery Runner类：执行SQL语句的类

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; 
//转换成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; 
//转换成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

提供的一个开源的API，是对javamail的封装。

//用commons email发送邮件 
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文件上传功能。

//官方示例：
//* 检查请求是否含有上传文件 
// Check that we have a file upload request 
boolean isMultipart = ServletFileUpload.isMultipartContent(request); 
//现在我们得到了items的列表 
//如果你的应用近于最简单的情况，上面的处理就够了。但我们有时候还是需要更多的控制。
//下面提供了几种控制选择：
// 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); 
// 设置最大上传大小 
upload.setSizeMax(yourMaxRequestSize); 
// 解析所有请求 
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，你需要进一步处理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); 
 } 
} 
//区分数据是否为简单的表单数据，如果是简单的数据：
// processFormField 
if (item.isFormField()) { 
 String name = item.getFieldName(); 
 String value = item.getString(); 
 //...省略步骤 
} 
//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(); 
 //...省略步骤 
} 
//对于这些item，我们通常要把它们写入文件，或转为一个流 
// Process a file upload 
if (writeToFile) { 
 File uploadedFile = new File(...); 
 item.write(uploadedFile); 
} else { 
 InputStream uploadedStream = item.getInputStream(); 
 //...省略步骤 
 uploadedStream.close(); 
} 
//或转为字节数组保存在内存中：
// Process a file upload in memory 
byte[] data = item.get(); 
//...省略步骤 
//如果这个文件真的很大，你可能会希望向用户报告到底传了多少到服务端，让用户了解上传的过程 
//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.HttpClient

基于HttpCore实 现的一个HTTP/1.1兼容的HTTP客户端，它提供了一系列可重用的客户端身份验证、HTTP状态保持、HTTP连接管理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) { 
 // 构造HttpClient的实例 
 HttpClient httpClient = new HttpClient(); 
 // 创建GET方法的实例 
 GetMethod getMethod = new GetMethod("http://www.ibm.com"); 
 // 使用系统提供的默认的恢复策略 
 getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, 
 new DefaultHttpMethodRetryHandler()); 
 try { 
 // 执行getMethod 
 int statusCode = httpClient.executeMethod(getMethod); 
 if (statusCode != HttpStatus.SC_OK) { 
 System.err.println("Method failed: " 
 + getMethod.getStatusLine()); 
 } 
 // 读取内容 
 byte[] responseBody = getMethod.getResponseBody(); 
 // 处理内容 
 System.out.println(new String(responseBody)); 
 } catch (HttpException e) { 
 // 发生致命的异常，可能是协议不对或者返回的内容有问题 
 System.out.println("Please check your provided http address!"); 
 e.printStackTrace(); 
 } catch (IOException e) { 
 // 发生网络异常 
 e.printStackTrace(); 
 } finally { 
 // 释放连接 
 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) { 
 // 构造HttpClient的实例 
 HttpClient httpClient = new HttpClient(); 
 // 创建POST方法的实例 
 String url = "http://www.oracle.com/"; 
 PostMethod postMethod = new PostMethod(url); 
 // 填入各个表单域的值 
 NameValuePair[] data = { new NameValuePair("id", "youUserName"), 
 new NameValuePair("passwd", "yourPwd") }; 
 // 将表单的值放入postMethod中 
 postMethod.setRequestBody(data); 
 // 执行postMethod 
 int statusCode = httpClient.executeMethod(postMethod); 
 // HttpClient对于要求接受后继服务的请求，象POST和PUT等不能自动处理转发 
 // 301或者302 
 if (statusCode == HttpStatus.SC_MOVED_PERMANENTLY || 
 statusCode == HttpStatus.SC_MOVED_TEMPORARILY) { 
 // 从头中取出转向的地址 
 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

对java.io的扩展 操作文件非常方便。

//1．读取Stream 
//标准代码：
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．读取文件 
File file = new File("/commons/io/project.properties"); 
List lines = FileUtils.readLines(file, "UTF-8"); 
//3．察看剩余空间 
long freeSpace = FileSystemUtils.freeSpace("C:/");

13.Lang

主要是一些公共的工具集合，比如对字符、数组的操作等等。

// 1 合并两个数组: org.apache.commons.lang. ArrayUtils 
// 有时我们需要将两个数组合并为一个数组，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 截取从from开始字符串 
StringUtils.substringAfter("SELECT * FROM PERSON ", "from"); 
//3 判断该字符串是不是为数字(0~9)组成，如果是，返回true 但该方法不识别有小数点和 请注意。
StringUtils.isNumeric("454534"); //返回true 
//4.取得类名 
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")); 
//6.五位的随机字母和数字 
System.out.println(RandomStringUtils.randomAlphanumeric(5)); 
//7.StringEscapeUtils 
System.out.println(StringEscapeUtils.escapeHtml("<html>")); 
//输出结果为<html> 
System.out.println(StringEscapeUtils.escapeJava("String")); 
//8.StringUtils,判断是否是空格字符 
System.out.println(StringUtils.isBlank(" ")); 
//将数组中的内容以,分隔 
System.out.println(StringUtils.join(test,",")); 
//在右边加下字符,使之总长度为6 
System.out.println(StringUtils.rightPad("abc", 6, 'T')); 
//首字母大写 
System.out.println(StringUtils.capitalize("abc")); 
//Deletes all whitespaces from a String 删除所有空格 
System.out.println( StringUtils.deleteWhitespace(" ab c ")); 
//判断是否包含这个字符 
System.out.println( StringUtils.contains("abc", "ba")); 
//表示左边两个字符 
System.out.println( StringUtils.left("abc", 2)); 
System.out.println(NumberUtils.stringToInt("33"));

14.Logging

提供的是一个Java 的日志接口,同时兼顾轻量级和不依赖于具体的日志实现工具。

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

通用验证系统，该组件提供了客户端和服务器端的数据验证框架。

1.验证日期

// 获取日期验证 
DateValidator validator = DateValidator.getInstance(); 
// 验证/转换日期 
Date fooDate = validator.validate(fooString, "dd/MM/yyyy"); 
if (fooDate == null) { 
 // 错误 不是日期 
 return; 
}

2.表达式验证

// 设置参数 
boolean caseSensitive = false; 
String regex1 = "^([A-Z]*)(?:\\-)([A-Z]*)*$" 
String regex2 = "^([A-Z]*)$"; 
String[] regexs = new String[] {regex1, regex1}; 
// 创建验证 
RegexValidator validator = new RegexValidator(regexs, caseSensitive); 
// 验证返回boolean 
boolean valid = validator.isValid("abc-def"); 
// 验证返回字符串 
String result = validator.validate("abc-def"); 
// 验证返回数组 
String[] groups = validator.match("abc-def");

3.配置文件中使用验证

<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> 
添加姓名验证. 
<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>

4.验证类

Excerpts from org.apache.commons.validator.RequiredNameTest 
//加载验证配置文件 
InputStream in = this.getClass().getResourceAsStream("validator-name-required.xml"); 
ValidatorResources resources = new ValidatorResources(in); 
//这个是自己创建的bean 我这里省略了 
Name name = new Name(); 
Validator validator = new Validator(resources, "nameForm"); 
//设置参数 
validator.setParameter(Validator.BEAN_PARAM, name); 
Map results = null; 
//验证 
results = validator.validate(); 
if (results.get("firstName") == null) { 
 //验证成功 
} else { 
 //有错误 int errors = ((Integer)results.get("firstName")).intValue(); 
}