看例子練apache commons之lang篇

duduwolf 2006-09-03

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看commons包時(shí)的相關(guān)練習(xí),可以用這個(gè)包提高編碼效率。

package org.raistlin.test.apache;

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import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Calendar;
import java.util.Date;
import java.util.Iterator;

import org.apache.commons.lang.ArrayUtils;
import org.apache.commons.lang.CharSet;
import org.apache.commons.lang.CharSetUtils;
import org.apache.commons.lang.ClassUtils;
import org.apache.commons.lang.ObjectUtils;
import org.apache.commons.lang.RandomStringUtils;
import org.apache.commons.lang.SerializationUtils;
import org.apache.commons.lang.StringEscapeUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang.SystemUtils;
import org.apache.commons.lang.builder.EqualsBuilder;
import org.apache.commons.lang.builder.HashCodeBuilder;
import org.apache.commons.lang.builder.ToStringBuilder;
import org.apache.commons.lang.builder.ToStringStyle;
import org.apache.commons.lang.math.NumberUtils;
import org.apache.commons.lang.time.DateFormatUtils;
import org.apache.commons.lang.time.DateUtils;
import org.apache.commons.lang.time.StopWatch;

public class LangDemo
{
public void charSetDemo()
{
System.out.println("**CharSetDemo**");
CharSet charSet = CharSet.getInstance("aeiou");
String demoStr = "The quick brown fox jumps over the lazy dog.";
int count = 0;
for (int i = 0, len = demoStr.length(); i < len; i++)
{
if (charSet.contains(demoStr.charAt(i)))
{
count++;

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}
}
System.out.println("count: " + count);
}

public void charSetUtilsDemo()
{
System.out.println("**CharSetUtilsDemo**");
System.out.println("計(jì)算字符串中包含某字符數(shù).");
System.out.println(CharSetUtils.count(
"The quick brown fox jumps over the lazy dog.", "aeiou"));

System.out.println("刪除字符串中某字符.");
System.out.println(CharSetUtils.delete(
"The quick brown fox jumps over the lazy dog.", "aeiou"));

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System.out.println("保留字符串中某字符.");
System.out.println(CharSetUtils.keep(
"The quick brown fox jumps over the lazy dog.", "aeiou"));

System.out.println("合并重復(fù)的字符.");
System.out.println(CharSetUtils.squeeze("a bbbbbb c dd", "b d"));
}

public void objectUtilsDemo()
{
System.out.println("**ObjectUtilsDemo**");
System.out.println("Object為null時(shí)，默認(rèn)打印某字符.");
Object obj = null;
System.out.println(ObjectUtils.defaultIfNull(obj, "空"));

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System.out.println("驗(yàn)證兩個(gè)引用是否指向的Object是否相等,取決于Object的equals()方法.");
Object a = new Object();
Object b = a;

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Object c = new Object();
System.out.println(ObjectUtils.equals(a, b));
System.out.println(ObjectUtils.equals(a, c));

System.out.println("用父類Object的toString()方法返回對(duì)象信息.");
Date date = new Date();
System.out.println(ObjectUtils.identityToString(date));
System.out.println(date);

System.out.println("返回類本身的toString()方法結(jié)果,對(duì)象為null時(shí)，返回0長度字符串.");
System.out.println(ObjectUtils.toString(date));
System.out.println(ObjectUtils.toString(null));
System.out.println(date);

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}

public void serializationUtilsDemo()
{
System.out.println("*SerializationUtils**");
Date date = new Date();
byte[] bytes = SerializationUtils.serialize(date);

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System.out.println(ArrayUtils.toString(bytes));
System.out.println(date);

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Date reDate = (Date) SerializationUtils.deserialize(bytes);
System.out.println(reDate);
System.out.println(ObjectUtils.equals(date, reDate));

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System.out.println(date == reDate);

FileOutputStream fos = null;
FileInputStream fis = null;
try
{
fos = new FileOutputStream(new File("d:/test.txt"));
fis = new FileInputStream(new File("d:/test.txt"));
SerializationUtils.serialize(date, fos);
Date reDate2 = (Date) SerializationUtils.deserialize(fis);

System.out.println(date.equals(reDate2));

}
catch (FileNotFoundException e)
{
e.printStackTrace();

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}
finally
{
try
{
fos.close();
fis.close();
}
catch (IOException e)
{
e.printStackTrace();
}
}

}

public void randomStringUtilsDemo()
{
System.out.println("**RandomStringUtilsDemo**");
System.out.println("生成指定長度的隨機(jī)字符串,好像沒什么用.");
System.out.println(RandomStringUtils.random(500));

System.out.println("在指定字符串中生成長度為n的隨機(jī)字符串.");
System.out.println(RandomStringUtils.random(5, "abcdefghijk"));

System.out.println("指定從字符或數(shù)字中生成隨機(jī)字符串.");

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System.out.println(RandomStringUtils.random(5, true, false));

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System.out.println(RandomStringUtils.random(5, false, true));

}

public void stringUtilsDemo()
{
System.out.println("**StringUtilsDemo**");
System.out.println("將字符串重復(fù)n次，將文字按某寬度居中，將字符串?dāng)?shù)組用某字符串連接.");
String[] header = new String[3];
header[0] = StringUtils.repeat("*", 50);
header[1] = StringUtils.center(" StringUtilsDemo ", 50, "^O^");
header[2] = header[0];
String head = StringUtils.join(header, "\n");
System.out.println(head);

System.out.println("縮短到某長度,用...結(jié)尾.");
System.out.println(StringUtils.abbreviate(
"The quick brown fox jumps over the lazy dog.", 10));
System.out.println(StringUtils.abbreviate(
"The quick brown fox jumps over the lazy dog.", 15, 10));

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System.out.println("返回兩字符串不同處索引號(hào).");
System.out.println(StringUtils.indexOfDifference("aaabc", "aaacc"));

System.out.println("返回兩字符串不同處開始至結(jié)束.");
System.out.println(StringUtils.difference("aaabcde", "aaaccde"));

System.out.println("截去字符串為以指定字符串結(jié)尾的部分.");
System.out.println(StringUtils.chomp("aaabcde", "de"));

System.out.println("檢查一字符串是否為另一字符串的子集.");
System.out.println(StringUtils.containsOnly("aad", "aadd"));

System.out.println("檢查一字符串是否不是另一字符串的子集.");
System.out.println(StringUtils.containsNone("defg", "aadd"));

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System.out.println("檢查一字符串是否包含另一字符串.");
System.out.println(StringUtils.contains("defg", "ef"));
System.out.println(StringUtils.containsOnly("ef", "defg"));

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System.out.println("返回可以處理null的toString().");
System.out.println(StringUtils.defaultString("aaaa"));
System.out.println("?" + StringUtils.defaultString(null) + "!");

System.out.println("去除字符中的空格.");
System.out.println(StringUtils.deleteWhitespace("aa bb cc"));

System.out.println("判斷是否是某類字符.");
System.out.println(StringUtils.isAlpha("ab"));
System.out.println(StringUtils.isAlphanumeric("12"));
System.out.println(StringUtils.isBlank(""));
System.out.println(StringUtils.isNumeric("123"));

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}

public void systemUtilsDemo()
{
System.out.println(genHeader("SystemUtilsDemo"));
System.out.println("獲得系統(tǒng)文件分隔符.");
System.out.println(SystemUtils.FILE_SEPARATOR);

System.out.println("獲得源文件編碼.");

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System.out.println(SystemUtils.FILE_ENCODING);

System.out.println("獲得ext目錄.");
System.out.println(SystemUtils.JAVA_EXT_DIRS);

System.out.println("獲得java版本.");
System.out.println(SystemUtils.JAVA_VM_VERSION);

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System.out.println("獲得java廠商.");
System.out.println(SystemUtils.JAVA_VENDOR);
}

public void classUtilsDemo()
{
System.out.println(genHeader("ClassUtilsDemo"));
System.out.println("獲取類實(shí)現(xiàn)的所有接口.");
System.out.println(ClassUtils.getAllInterfaces(Date.class));

System.out.println("獲取類所有父類.");
System.out.println(ClassUtils.getAllSuperclasses(Date.class));

System.out.println("獲取簡(jiǎn)單類名.");
System.out.println(ClassUtils.getShortClassName(Date.class));

System.out.println("獲取包名.");
System.out.println(ClassUtils.getPackageName(Date.class));

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System.out.println("判斷是否可以轉(zhuǎn)型.");
System.out.println(ClassUtils.isAssignable(Date.class, Object.class));
System.out.println(ClassUtils.isAssignable(Object.class, Date.class));
}

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public void stringEscapeUtilsDemo()
{
System.out.println(genHeader("StringEcsapeUtils"));
System.out.println("轉(zhuǎn)換特殊字符.");
System.out.println("html:" + StringEscapeUtils.escapeHtml("

"));
System.out.println("html:"
+ StringEscapeUtils.unescapeHtml("<p>"));
}

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private final class BuildDemo
{
String name;

int age;

public BuildDemo(String name, int age)
{
this.name = name;
this.age = age;
}

public String toString()
{
ToStringBuilder tsb = new ToStringBuilder(this,
ToStringStyle.MULTI_LINE_STYLE);
tsb.append("Name", name);
tsb.append("Age", age);
return tsb.toString();
}

public int hashCode()
{
HashCodeBuilder hcb = new HashCodeBuilder();
hcb.append(name);
hcb.append(age);
return hcb.hashCode();
}

public boolean equals(Object obj)
{
if (!(obj instanceof BuildDemo))
{
return false;
}
BuildDemo bd = (BuildDemo) obj;
EqualsBuilder eb = new EqualsBuilder();
eb.append(name, bd.name);

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eb.append(age, bd.age);
return eb.isEquals();
}
}

public void builderDemo()
{

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System.out.println(genHeader("BuilderDemo"));
BuildDemo obj1 = new BuildDemo("a", 1);
BuildDemo obj2 = new BuildDemo("b", 2);
BuildDemo obj3 = new BuildDemo("a", 1);

System.out.println("toString()");
System.out.println(obj1);
System.out.println(obj2);
System.out.println(obj3);

System.out.println("hashCode()");
System.out.println(obj1.hashCode());
System.out.println(obj2.hashCode());
System.out.println(obj3.hashCode());

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System.out.println("equals()");
System.out.println(obj1.equals(obj2));

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System.out.println(obj1.equals(obj3));
}

public void numberUtils()
{
System.out.println(genHeader("NumberUtils"));
System.out.println("字符串轉(zhuǎn)為數(shù)字(不知道有什么用).");
System.out.println(NumberUtils.stringToInt("ba", 33));

System.out.println("從數(shù)組中選出最大值.");
System.out.println(NumberUtils.max(new int[] { 1, 2, 3, 4 }));

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System.out.println("判斷字符串是否全是整數(shù).");
System.out.println(NumberUtils.isDigits("123.1"));

System.out.println("判斷字符串是否是有效數(shù)字.");
System.out.println(NumberUtils.isNumber("0123.1"));

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}

public void dateFormatUtilsDemo()
{
System.out.println(genHeader("DateFormatUtilsDemo"));
System.out.println("格式化日期輸出.");
System.out.println(DateFormatUtils.format(System.currentTimeMillis(),
"yyyy-MM-dd HH:mm:ss"));

System.out.println("秒表.");

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StopWatch sw = new StopWatch();

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sw.start();

for (Iterator iterator = DateUtils.iterator(new Date(),
DateUtils.RANGE_WEEK_CENTER); iterator.hasNext();)
{
Calendar cal = (Calendar) iterator.next();
System.out.println(DateFormatUtils.format(cal.getTime(),
"yy-MM-dd HH:mm"));
}

sw.stop();
System.out.println("秒表計(jì)時(shí):" + sw.getTime());

}

private String genHeader(String head)
{
String[] header = new String[3];
header[0] = StringUtils.repeat("*", 50);

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header[1] = StringUtils.center(" " + head + " ", 50, "^O^");
header[2] = header[0];
return StringUtils.join(header, "\n");
}

/**

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* @param args
*/
public static void main(String[] args)
{
LangDemo langDemo = new LangDemo();

langDemo.charSetDemo();
langDemo.charSetUtilsDemo();
langDemo.objectUtilsDemo();
langDemo.serializationUtilsDemo();
langDemo.randomStringUtilsDemo();
langDemo.stringUtilsDemo();
langDemo.systemUtilsDemo();
langDemo.classUtilsDemo();
langDemo.stringEscapeUtilsDemo();
langDemo.builderDemo();
langDemo.numberUtils();
langDemo.dateFormatUtilsDemo();

}

}

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