Google-Guava工具类整理

更详细整理： http://blog.csdn.net/alecf/article/details/24775979
原文： http://my.oschina.net/shma1664/blog/596904

源码包的简单说明：
com.google.common.annotations：普通注解类型。
com.google.common.base：基本工具类库和接口。
com.google.common.cache：缓存工具包，非常简单易用且功能强大的JVM内缓存。
com.google.common.collect：带泛型的集合接口扩展和实现，以及工具类，这里你会发现很多好玩的集合。
com.google.common.eventbus：发布订阅风格的事件总线。
com.google.common.hash：哈希工具包。
com.google.common.io：I/O工具包。
com.google.common.math：原始算术类型和超大数的运算工具包。
com.google.common.net：网络工具包。
com.google.common.primitives：八种原始类型和无符号类型的静态工具包。
com.google.common.reflect：反射工具包。
com.google.common.util.concurrent：多线程工具包。

1、基本功能1）字符串操作

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Java代码

package com.shma.guava.base;

import java.util.Map;

import org.junit.Test;

import com.google.common.base.Joiner;

import com.google.common.base.Splitter;

import com.google.common.base.Strings;

import com.google.common.collect.Maps;

/**

* 字符串处理

* @author admin

public class StringsTest {

/**

* 判断是否为空

@Test

public void testIsNullOrEmpty() {

String name = "";

System.out.println(Strings.isNullOrEmpty(name)); //true

String name2 = null;

System.out.println(Strings.isNullOrEmpty(name2)); //true

String name3 = "shma";

System.out.println(Strings.isNullOrEmpty(name3)); //false

}

/**

* 截取两个字符串的相同前缀

@Test

public void testCommonPrefix() {

// 两个字符串相同的前缀或者后缀

String aString = "hi,a.shma.hello";

String bString = "hi,b.jjq.hello";

System.out.println(Strings.commonPrefix(aString, bString)); //hi,

}

/**

* 截取两个字符串的相同后缀

@Test

public void testCommonSuffix() {

// 两个字符串相同的前缀或者后缀

String aString = "hi,a.shma.hello";

String bString = "hi,b.jjq.hello";

System.out.println(Strings.commonSuffix(aString, bString)); //.hello

}

/**

* 字符串补全

@Test

public void testPad() {

int minLength = 5;

//末尾以0补全

String padEndResult = Strings.padEnd("123", minLength, '0');

System.out.println(padEndResult); //12300

//开始补全

String padStartResult = Strings.padStart("123", minLength, '0');

System.out.println(padStartResult); //00123

}

/**

* 拆分字符串

@Test

public void testSplitter() {

Iterable<String> iterable = Splitter.onPattern("[,，;]")

.trimResults()

.omitEmptyStrings()

.split("马韶华,张琦，笑笑,,老李，类型哈哈，非也; 宵夜 ");

for(String item : iterable) {

System.out.println(item);

}

//二次拆分

String toSplitString = "a=1; b=2, c=3";

Map<String, String> kvs = Splitter.onPattern("[;,]")

.trimResults()

.omitEmptyStrings()

.withKeyValueSeparator("=")

.split(toSplitString);

System.out.println(kvs); //{a=1, b=2, c=3}

}

/**

* 字符串合并

@Test

public void testJoin() {

String users = Joiner.on(",").join(new String[]{"张三", "李四", "王五"});

System.out.println(users); //张三,李四,王五

//将Map<String, String>合并

Map<String, String> dataMap = Maps.newHashMap();

dataMap.put("1001", "张三");

dataMap.put("1002", "李四");

dataMap.put("1003", "王五");

dataMap.put("1004", "马六");

String mapString = Joiner.on(",").withKeyValueSeparator("=").join(dataMap);

System.out.println(mapString); // 1003=王五,1004=马六,1001=张三,1002=李四

}

/**

* 重复输出次数

@Test

public void testRepeat() {

System.out.println(Strings.repeat("1234", 2)); // 12341234

}

2）对象封装：Objects

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Java代码

package com.shma.guava2.base;

import org.junit.Test;

import com.google.common.base.Objects;

import com.google.common.collect.ComparisonChain;

/**

* 复写Object中的方法实现

* @author admin

public class ObjectsTest {

/**

* 比较大小

@Test

public void compareTest() {

Person person1 = new Person("jqq", 24);

Person person2 = new Person("jqq", 28);

Person person3 = new Person("shma", 24);

Person person4 = new Person("shma", 21);

Person person5 = new Person("shma", 21);

System.out.println(person1.compareTo(person2));

System.out.println(person1.compareTo(person3));

System.out.println(person3.compareTo(person4));

System.out.println(person5.compareTo(person4));

}

/**

* 实现toString

@Test

public void toStringTest() {

System.out.println(Objects.toStringHelper(this).add("name", "shma").toString());

System.out.println(Objects.toStringHelper(Person.class).add("name", "shma").add("age", 23).toString());

Person person1 = new Person("jqq", 24);

Person person2 = new Person("jqq", 24);

System.out.println(person1);

System.out.println(person2);

System.out.println(person1.hashCode());

System.out.println(person2.hashCode());

System.out.println(person1.equals(person2));

}

/**

* 判断equals

@Test

public void equalsTest() {

System.out.println(Objects.equal(null, "a")); //false

System.out.println(Objects.equal("a", "a")); //true

System.out.println(Objects.equal("", "")); //true

System.out.println(Objects.equal("a", "")); //false

System.out.println(Objects.equal(null, null)); //true

System.out.println(Objects.equal(new Person("shma", 23), new Person("shma", 23))); //false

Person person = new Person("jqq", 24);

System.out.println(Objects.equal(person, person)); //true

}

/**

* 计算hashcode

@Test

public void hashCodeTest() {

System.out.println(Objects.hashCode("a")); //128

System.out.println(Objects.hashCode("a", "b")); //4066

System.out.println(Objects.hashCode("b", "a")); //4096

System.out.println(Objects.hashCode("b", "a", "c")); //127075

System.out.println(Objects.hashCode("a", "c", "b")); //126175

System.out.println(Objects.hashCode(new Person("shma", 23))); //21648900

System.out.println(Objects.hashCode(new Person("shma", 23))); //21846074

Person person = new Person("jqq", 24);

System.out.println(Objects.hashCode(person)); //13856786

}

class Person implements Comparable<Person> {

public String name;

public int age;

Person(String name, int age) {

this.name = name;

this.age = age;

}

@Override

public String toString() {

return Objects.toStringHelper(Person.class)

.add("name", this.name)

.add("age", this.age)

.toString();

}

@Override

public int hashCode() {

return Objects.hashCode(name, age);

}

@Override

public boolean equals(Object obj) {

if (this == obj)

return true;

if (obj == null)

return false;

if (getClass() != obj.getClass())

return false;

Person other = (Person) obj;

if(this.name == other.name && this.age == other.age)

return true;

return false;

}

@Override

public int compareTo(Person perosn) {

return ComparisonChain.start()

.compare(this.name, perosn.name)

.compare(this.age, perosn.age)

.result();

}

class Student implements Comparable<Student> {

private String name;

private int age;

private int score;

public Student() {

super();

}

public Student(String name, int age, int score) {

super();

this.name = name;

this.age = age;

this.score = score;

}

@Override

public String toString() {

return Objects.toStringHelper(this)

.add("name", name)

.add("age", age)

.add("score", score)

.toString();

}

@Override

public int hashCode() {

return Objects.hashCode(name, age);

}

@Override

public boolean equals(Object obj) {

if (obj instanceof Student) {

Student that = (Student) obj;

return Objects.equal(name, that.name)

&& Objects.equal(age, that.age)

&& Objects.equal(score, that.score);

}

return false;

}

@Override

public int compareTo(Student student) {

return ComparisonChain.start()

.compare(this.name, student.name)

.compare(this.age, student.age)

.compare(this.score, student.score)

.result();

}

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Google-Guava工具类整理

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