Apache Commons 工具类介绍及简单使用
Apache Commons包含了很多开源的工具，用于解决平时编程经常会遇到的问题，减少重复劳动。下面是我这几年做开发过程中自己用过的工具类做简单介绍。
| 组件 | 功能介绍 |
| commons-beanutils | 提供了对于JavaBean进行各种操作，克隆对象,属性等等. |
| commons-betwixt | XML与Java对象之间相互转换. |
| commons-codec | 处理常用的编码方法的工具类包 例如DES、SHA1、MD5、Base64等. |
| commons-collections | java集合框架操作. |
| commons-compress | java提供文件打包 压缩类库. |
| commons-configuration | 一个java应用程序的配置管理类库. |
| commons-dbcp | 提供数据库连接池服务. |
| commons-dbutils | 提供对jdbc 的操作封装来简化数据查询和记录读取操作. |
| commons-email | java发送邮件 对javamail的封装. |
| commons-fileupload | 提供文件上传功能. |
| commons-httpclient | 提供HTTP客户端与服务器的各种通讯操作. 现在已改成HttpComponents |
| commons-io | io工具的封装. |
| commons-lang | Java基本对象方法的工具类包 如：StringUtils,ArrayUtils,DateUtils,DateFormatUtils等等. |
| commons-logging | 提供的是一个Java 的日志接口. |
| commons-validator | 提供了客户端和服务器端的数据验证框架. |
1、commons-beanutils
提供了对于JavaBean进行各种操作， 比如对象,属性复制等等。
Java代码 
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.beanutils.PropertyUtils;
public class CommonsBeanUtils {
public static void main(String[] args) throws Exception {
// ****************************************************************************
Person person = new Person();
person.setName("tom");
person.setAge(21);
// 克隆对象
Person person2 = (Person) BeanUtils.cloneBean(person);
System.out.println(person2.getName() + ">>" + person2.getAge());
// ****************************************************************************
Map<String, String> map = new HashMap<String, String>();
map.put("name", "tom");
map.put("email", "tom@");
map.put("age", "21");
// 将map转化为一个Person对象
Person person3 = new Person();
BeanUtils.populate(person3, map);
System.out.println(person3.getName() + ">>" + person3.getAge());
// 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<String, String> map2 = BeanUtils.describe(person3);
System.out.println(map2.get("name") + ">>" + map2.get("age"));
// ****************************************************************************
Person person4 = new Person();
person4.setName("andy");
// 反射调用get方法
String name = (String) PropertyUtils.getProperty(person4, "name");
System.out.println(name);
// 反射调用set方法
PropertyUtils.setProperty(person4, "age", 25);
System.out.println(person4.getAge());
}
}
2、commons-betwixt
XML与Java对象之间相互转换。
Java代码
import java.io.StringReader;
import java.io.StringWriter;
import org.apache.commons.betwixt.io.BeanReader;
import org.apache.commons.betwixt.io.BeanWriter;
public class CommonsBetwixt {
public static void main(String[] args) throws Exception {
// ****************************创建一个例子Bean，并将它转化为XML ************************************************
// 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 Person("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();
// ****************************将XML转化为JavaBean ************************************************
// 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", Person.class);
// 现在我们对XML进行解析
Person person = (Person) beanReader.parse(xmlReader);
// 输出结果
System.out.println(person);
}
}
3、commons-codec
提供了一些公共的编解码实现，比如Base64, Hex, MD5,Phonetic and URLs等等。
package com.somnus.apache;
import java.util.Arrays;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.Hex;
public class CommonsCodec {
public static void main(String[] args) throws Exception {
String encode = Base64.encodeBase64String("Somnus罂粟花".getBytes(/*"UTF-8"*/));
System.out.println("Base64 编码后：" + encode);
byte[] decode = Base64.decodeBase64("U29tbnVz");
String decodestr = new String(decode);
System.out.println("Base64 解码后："+decodestr);
System.out.println("*********************************************************");
byte[] buff = "Somnus罂粟花".getBytes(/*"utf-8"*/);
System.out.println(Arrays.toString(buff));
String byte2hex = Hex.encodeHexString(buff);
System.out.println(byte2hex);
byte[] hex2byte = Hex.decodeHex(byte2hex.toCharArray());
System.out.println(Arrays.toString(hex2byte));
System.out.println(new String(hex2byte));
}
}
4、commons-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
Java代码
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import org.apache.commons.collections.BidiMap;
import org.apache.commons.collections.CollectionUtils;
import org.apache.commons.collections.OrderedMap;
import org.apache.commons.collections.bidimap.TreeBidiMap;
import org.apache.commons.collections.map.LinkedMap;
public class CommonsCollections {
public static void main(String[] args) {
//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、commons-compress
commons compress中的打包、压缩类库。
Java代码
import java.io.File;
import java.io.FileInputStream;
import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
import org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream;
public class CommonsCompress {
public static void main(String[] args) throws Exception {
// 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、commons-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
package com.somnus.apache;
import java.util.Iterator;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.PropertiesConfiguration;
/**
* @description: TODO
* @author Somnus date 2015年4月1日 下午6:18:16
*/
public class CommonsConfiguration {
public void configuration() {
try {
String url = getClass().getClassLoader().getResource("info.properties").getPath();
System.out.println(url);
PropertiesConfiguration config = new PropertiesConfiguration(url);
config.setProperty("age", "22");
config.save();
Integer age = config.getInt("age");
String password = config.getString("username");
System.out.println(age);
System.out.println(password);
for(Iterator<String> it = config.getKeys();it.hasNext();){
String key = (String)it.next();
String value = config.getString(key);
System.out.println(key +"="+value);
}
} catch (ConfigurationException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
CommonsConfiguration config = new CommonsConfiguration();
config.configuration();
}
}
7、commons-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。
Java代码
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.sql.DataSource;
import org.apache.commons.dbcp.ConnectionFactory;
import org.apache.commons.dbcp.DriverManagerConnectionFactory;
import org.apache.commons.dbcp.PoolableConnectionFactory;
import org.apache.commons.dbcp.PoolingDataSource;
import org.apache.commons.pool.ObjectPool;
import org.apache.commons.pool.impl.GenericObjectPool;
public class CommonsDbcp {
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, null, null, connectURI, false, false);
// 获取GenericObjectPool 连接的实例
ObjectPool connectionPool = new GenericObjectPool(poolableConnectionFactory);
// 创建 PoolingDriver
PoolingDataSource dataSource = new PoolingDataSource(connectionPool);
return dataSource;
}
}
8、commons-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
Java代码
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.List;
import java.util.Map;
import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
public class CommonsDbutils {
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);
//****************************转换成list ************************************
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("age:" + p.getAge() + ",name:" + p.getName());
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DbUtils.closeQuietly(conn);
}
//****************************转换成map ************************************
try {
conn = DriverManager.getConnection(url, user, password);
QueryRunner qr = new QueryRunner();
List results = (List) qr.query(conn, "select age,name from person",new MapListHandler());
for (int i = 0; i < results.size(); i++) {
Map map = (Map) results.get(i);
System.out.println("age:" + map.get("age") + ",name:"+ map.get("name"));
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DbUtils.closeQuietly(conn);
}
}
}
9、commons-email
提供的一个开源的API，是对javamail的封装。
Java代码
import org.apache.commons.mail.DefaultAuthenticator;
import org.apache.commons.mail.Email;
import org.apache.commons.mail.EmailException;
import org.apache.commons.mail.SimpleEmail;
public class CommosEmail {
public static void main(String[] args) throws EmailException {
Email email = new SimpleEmail();
email.setHostName("smtp.googlemail.com");
email.setSmtpPort(465);
email.setAuthenticator(new DefaultAuthenticator("username", "password"));
email.setSSLOnConnect(true);
email.setFrom("[email protected]");
email.setSubject("TestMail");
email.setMsg("This is a test mail ... :-)");
email.addTo("[email protected]");
email.send();
}
}
10、commons-fileupload
java web文件上传功能。
Java代码
- //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、commons-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。
Java代码
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 CommonsHttpclient {
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();
}
// 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、commons-io
对java.io的扩展 操作文件非常方便。
package com.somnus.apache;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.util.Arrays;
import java.util.List;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.io.FileSystemUtils;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
/**
* @Title: CommonsIo.java
* @Package com.somnus.apache
* @Description: TODO
* @author Somnus
* @date 2015年5月27日 下午3:06:39
* @version V1.0
*/
public class CommonsIo {
public static void main(String[] args) throws Exception {
InputStream is1 = new URL("https://www.baidu.com/").openStream();
/**
* readLines(InputStream input)
* readLines(InputStream input, String encoding)
* readLines(Reader input)
*/
List<String> lines = IOUtils.readLines(is1);
for(String line:lines){
System.out.println(line);
}
System.out.println("******************************************************************************************");
InputStream is2 = new URL("https://www.baidu.com/").openStream();
try {
/**
* toString(InputStream input)
* toString(InputStream input, String encoding)
* toString(Reader input)
* [toString(byte[] input)]
* [toString(byte[] input, String encoding)]
*/
System.out.println(IOUtils.toString(is2));
} finally {
IOUtils.closeQuietly(is2);
}
System.out.println("******************************************************************************************");
File file = new File("src/main/resources/build.xml");
List<String> lines2 = FileUtils.readLines(file/*, "UTF-8"*/);
for(String line:lines2){
System.out.println(line);
}
System.out.println("******************************************************************************************");
String result = FileUtils.readFileToString(file/*, "UTF-8"*/);
System.out.println(result);
System.out.println("******************************************************************************************");
File srcFile = new File("src/main/resources/build.xml");
File destFile = new File("target/classes/build.txt");
/**
* copyFile(File srcFile, File destFile)
* copyFile(File srcFile, File destFile,boolean preserveFileDate)
*/
FileUtils.copyFile(srcFile, destFile);
System.out.println("******************************************************************************************");
InputStream is4 = new URL("https://www.baidu.com/").openStream();
OutputStream os4 = new FileOutputStream(new File("target/classes/baidu.txt"));
try {
/**
* copy(InputStream input, OutputStream output)
* copy(InputStream input, Writer output)
* copy(InputStream input, Writer output, String encoding)
* copy(Reader input, Writer output)
* copy(Reader input, OutputStream output)
* copy(Reader input, OutputStream output, String encoding)
* copyLarge(Reader input, Writer output)
* copyLarge(InputStream input, OutputStream output)
*/
IOUtils.copy(is4, os4);
} finally{
IOUtils.closeQuietly(is4);
IOUtils.closeQuietly(os4);
}
System.out.println("******************************************************************************************");
InputStream is5 = new URL("https://www.baidu.com/").openStream();
try {
/**
* toByteArray(InputStream input)
* toByteArray(Reader input)
* toByteArray(Reader input, String encoding)
* [toByteArray(String input)]
*/
byte[] buff5 = IOUtils.toByteArray(is5);
System.out.println(Hex.encodeHexString(buff5));
} finally{
IOUtils.closeQuietly(is5);
}
System.out.println("******************************************************************************************");
InputStream is6 = new URL("https://www.baidu.com/").openStream();
try {
/**
* toCharArray(InputStream is)
* toCharArray(InputStream is, String encoding)
* toCharArray(Reader input)
*/
char[] buff6 = IOUtils.toCharArray(is6);
System.out.println(Arrays.toString(buff6));
} finally{
IOUtils.closeQuietly(is6);
}
System.out.println("******************************************************************************************");
/**
* toInputStream(String input)
* toInputStream(String input, String encoding)
* toInputStream(CharSequence input)
* toInputStream(CharSequence input, String encoding)
*/
InputStream is7 = IOUtils.toInputStream("https://www.baidu.com/");
System.out.println("******************************************************************************************");
OutputStream os7 = new FileOutputStream(new File("target/classes/Somnus.txt"));
try {
/**
* write(byte[] data, OutputStream output)
* write(byte[] data, Writer output)
* write(byte[] data, Writer output, String encoding)
* write(char[] data, Writer output)
* write(char[] data, OutputStream output)
* write(char[] data, OutputStream output, String encoding)
* write(CharSequence data, Writer output)
* write(CharSequence data, OutputStream output)
* write(CharSequence data, OutputStream output, String encoding)
* write(String data, Writer output)
* write(String data, OutputStream output)
* write(String data, OutputStream output, String encoding)
*
*/
IOUtils.write("Somnus罂粟花", os7);
} finally{
IOUtils.closeQuietly(os7);
}
//察看剩余空间
long freeSpace = FileSystemUtils.freeSpace("C:/");
System.out.println(freeSpace);
}
}
13、commos-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。
package com.somnus.apache;
import java.util.Calendar;
import java.util.Date;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.ClassUtils;
import org.apache.commons.lang3.RandomStringUtils;
import org.apache.commons.lang3.StringEscapeUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.time.DateFormatUtils;
import org.apache.commons.lang3.time.DateUtils;
public class CommonsLang {
public static void main(String[] args) throws Exception {
// 将两个数组合并为一个数组
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());
System.out.println("********************************ArrayUtils***************************************");
// 取得类名
System.out.println(ClassUtils.getShortClassName(CommonsLang.class));
// 取得其包名
System.out.println(ClassUtils.getPackageName(CommonsLang.class));
// 五位的随机字母和数字
System.out.println(RandomStringUtils.randomAlphanumeric(5));
System.out.println("********************************ClassUtils***************************************");
System.out.println(StringEscapeUtils.escapeHtml3("<html>"));
// 输出结果为<html>
System.out.println(StringEscapeUtils.escapeJava("String"));
System.out.println("********************************StringEscapeUtils***************************************");
// 截取从from开始字符串
System.out.println(StringUtils.substringAfter("SELECT * FROM PERSON " , "FROM"));
// 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
System.out.println(StringUtils.isNumeric("454534"));// 返回true
// StringUtils,判断是否是空格字符
/**
* StringUtils.isBlank(null) = true
* StringUtils.isBlank("") = true
* StringUtils.isBlank(" ") = true
* StringUtils.isBlank("bob") = false
* StringUtils.isBlank(" bob ") = false
*/
System.out.println(StringUtils.isBlank(" "));
/**
* StringUtils.isEmpty(null) = true
* StringUtils.isEmpty("") = true
* StringUtils.isEmpty(" ") = false
* StringUtils.isEmpty("bob") = false
* StringUtils.isEmpty(" bob ") = false
*/
System.out.println(StringUtils.isEmpty(" "));
// 将数组中的内容以,分隔
System.out.println(StringUtils.join(new String[] { "1", "2", "3" }, ","));
// 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("********************************StringUtils***************************************");
System.out.println(DateFormatUtils.format(new Date(), "yyyy-MM-dd HH:mm:ss"));
//直接将日期格式化为内置的固定格式
System.out.println(DateFormatUtils.ISO_DATE_FORMAT.format(new Date()));
//字符型日期转化为Date
System.out.println(DateUtils.parseDate("2014-11-11 11:11:11", new String[] { "yyyy-MM-dd HH:mm:ss", "yyyy-MM-dd HH:mm", "yyyy-MM-dd", "yyyy/MM/dd" }));
//日期舍入与截整
System.out.println(DateUtils.truncate(new Date(), Calendar.DATE));
//判断是否是同一天
System.out.println(DateUtils.isSameDay(new Date(), new Date()));
//加天数
System.out.println(DateUtils.addDays(new Date(), 10));
System.out.println("********************************DateUtils***************************************");
}
}
14、commos-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。
Java代码
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class CommosLogging {
private static Log log = LogFactory.getLog(CommosLogging.class);
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。
验证日期
Java代码
- // 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;
- }
表达式验证
Java代码
- // 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");
配置文件中使用验证
Xml代码
- <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>
验证类
Java代码
- 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();
- }