关于 google的guava公共库的测试demo

最近在学习，guava公共库的一些基本功能，确实的是可以提高开发效率，并且有些地方确实很好用。

代码可以直接打开需要测试的地方进行运行。

不包含，net，事件总线，并发编程，反射和缓存。

手册地址：http://tool.oschina.net/apidocs/apidoc?api=guava

中文学习：http://ifeve.com/google-guava-using-and-avoiding-null

总的来说，印象深刻的就是，multiset和multimap这2个概念，很有用。当然还是有很多精彩的细节地方，学会了事半功倍。学习测试一下api吧

package com.iqoo.common;

import java.io.File;
import java.io.IOException;
import java.sql.SQLException;
import java.util.List;

import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import org.junit.Test;

import com.google.common.base.Charsets;
import com.google.common.base.Objects;
import com.google.common.io.Files;

/**
* Created by hank on 2016/6/3.
*/
public class demo {

@Test
public void test() throws IOException, SQLException, InvalidFormatException {
// optional 模拟，对象引用为null，返回默认值
// Optional possible = Optional.fromNullable(null);
// System.out.println(possible.or(2));

// 提前条件预判，抛出异常
// Preconditions.checkNotNull(null,"this is error");

// objects判断null相等
// System.out.println(Objects.equal(null, null));

// hashcode通过传入不同的字段，自动计算
// System.out.println(Objects.hashCode("han","kun"));
// System.out.println(Objects.hashCode("han","kun",1));
// System.out.println(Objects.hashCode("han","kun",1));

// toStringHelper编写调试
// System.out.println(Objects.toStringHelper(this).add("name", "hank").toString());

// compareTo这种对比，多个字段的时候
// System.out.println(ComparisonChain.start().compare(1, 3).result());
// System.out.println(ComparisonChain.start().compare('a', 'b').result());

// ordering比较器
// List<Integer> list = Lists.newArrayList();
// list.add(1);
// list.add(2);
// list.add(3);
// list.add(11);
// list.add(21);
// Ordering<Integer> naturalOrdering = Ordering.natural();
// Ordering<Object> usingToStringOrdering = Ordering.usingToString();
// Ordering<Object> arbitraryOrdering = Ordering.arbitrary();
// System.out.println("自然顺序(数字大小):"+ naturalOrdering.sortedCopy(list));
// System.out.println("字符串顺序:"+ usingToStringOrdering.sortedCopy(list));
// System.out.println("随机顺序:"+ arbitraryOrdering.sortedCopy(list));

// 捕获异常后，继续抛出异常
// try {
// int a = 1;
// throw new IOException();
// throw new SQLException();
// }
// catch (Throwable t) {
// 只有io异常抛出
// Throwables.propagateIfInstanceOf(t, IOException.class);
// 只有sql异常抛出
// Throwables.propagateIfInstanceOf(t, SQLException.class);
// 只有Error或RuntimeException异常抛出
// Throwables.propagateIfPossible(t);
// Error或RuntimeException，直接抛出
// throw Throwables.propagate(t);
// }

// 不可变集合
// final ImmutableSet<String> colors = ImmutableSet.of("red","blue","green");
// ImmutableList<String> colorsList = colors.asList();
// System.out.println(colors.size());
// 重复的set
// Multiset m = HashMultiset.create();
// m.add("han");
// m.add("han");
// m.add("han");
// m.add("kun");
// System.out.println(m.count("han"));

// Multimap<String, String> myMultimap = ArrayListMultimap.create();
//
// 添加键值对
// myMultimap.put("Fruits", "Bannana");
// 给Fruits元素添加另一个元素
// myMultimap.put("Fruits", "Apple");
// myMultimap.put("Fruits", "Pear");
// myMultimap.put("Vegetables", "Carrot");
// myMultimap.put("Fruits", "Bannana");
// System.out.println(myMultimap.get("Fruits"));

// Multimap<String,String> map = HashMultimap.create();
// map.put("name","han");
// map.put("name","kkkk");
// map.put("yourname","xxx");
// map.put("yourname","yyy");
// map.put("yourname","www");
// System.out.println(map.get("name"));
// System.out.println(map.size());
// System.out.println(map.keySet());
// 区别，一个为空集合，一个为null
// System.out.println(map.get("hello"));
// System.out.println(map.asMap().get("hello"));

// BiMap<String, Integer> userId = HashBiMap.create();
// userId.put("hank",123);
// 反向映射
// System.out.println(userId.forcePut("hank",345));
// System.out.println(userId.inverse().get(123));
// System.out.println(userId.inverse().get(345));

// 二维坐标确定一个值
// Table<Integer, Integer, String> pos = HashBasedTable.create();
// pos.put(1,1,"han");
// pos.put(1,2,"hello");
// pos.put(2,1,"world");
// pos.put(2,2,"kun");
// System.out.println(pos.row(1));
// System.out.println(pos.column(1));
// System.out.println(pos.cellSet().size());

// RangeSet<Integer> range = TreeRangeSet.create();
// range.add(Range.open(1,2));
// range.add(Range.open(2,3));
// range.add(Range.open(4,5));
// range.add(Range.open(6,10));
// 包含所有区间的最小区间
// System.out.println(range.span());
// System.out.println(range);
// 区间补集
// System.out.println(range.complement());
// System.out.println(range.asRanges());
// System.out.println(range.contains(2));
// 返回包含的区间
// System.out.println(range.rangeContaining(2));
// 是否包含区间
// System.out.println(range.encloses(Range.open(3,4)));
// System.out.println(range.encloses(Range.open(4,5)));
// System.out.println(range.encloses(Range.open(5,6)));
// System.out.println(range.encloses(Range.open(5,7)));
// 是否和子区间相交
// System.out.println(range.subRangeSet(Range.open(3,4)).isEmpty());
// System.out.println(range.subRangeSet(Range.open(4,5)).isEmpty());
// System.out.println(range.subRangeSet(Range.open(5,6)).isEmpty());
// System.out.println(range.subRangeSet(Range.open(5,7)).isEmpty());

// RangeMap<Integer,String> map = TreeRangeMap.create();
// map.put(Range.open(1,2),"han");
// map.put(Range.open(2,3),"kun");
// System.out.println(map);
// 注意区别，覆盖了上面的区间
// map.put(Range.open(1,3),"hello");
// System.out.println(map);

// List<String> theseElements = Lists.newArrayList("alpha", "beta", "gamma");
// System.out.println(theseElements);

// Iterable<Integer> concatenated = Iterables.concat(
// Ints.asList(1, 2, 3),
// Ints.asList(4, 5, 6)); // concatenated包括元素 1, 2, 3, 4, 5, 6
// System.out.println(concatenated);
// List countUp = Ints.asList(1, 2, 3, 4, 5);
// System.out.println(countUp);
// List countDown = Lists.reverse(countUp); // {5, 4, 3, 2, 1}
// System.out.println(countDown);
// List<List> parts = Lists.partition(countUp, 2);//{{1,2}, {3,4}, {5}}
// System.out.println(parts);

// List strs = Lists.newArrayList("han","hello","name");
// 索引必须唯一，否则报错
// ImmutableMap<Integer, String> map = Maps.uniqueIndex(strs, new Function<String, Integer>() {
// @Override
// public Integer apply(String st) {
// return st.length();
// }
// });
// System.out.println(map);

// ImmutableSet<String> set = ImmutableSet.of("aaa","bbb","c","dd","ee","ff","gg");
// Function<String,Integer> function = new Function<String, Integer>() {
// @Override
// public Integer apply(String s) {
// return s.length();
// }
// };
// ImmutableListMultimap<Integer,String> list = Multimaps.index(set,function);
// System.out.println(list);
// 翻转映射
// ArrayListMultimap<String,Integer> map = ArrayListMultimap.create();
// map.putAll("a", Ints.asList(1,2,3));
// map.putAll("b", Ints.asList(4,2,3));
// map.putAll("c", Ints.asList(4,5,3));
// TreeMultimap<Integer,String> inverse = Multimaps.invertFrom(map,TreeMultimap.<Integer, String>create());
// System.out.println(inverse);

// Map<String,Integer> map = ImmutableMap.of("a",1,"b",1,"c",2);
// SetMultimap setMultimap = Multimaps.forMap(map);
// Multimap<Integer,String> inverse = Multimaps.invertFrom(setMultimap, HashMultimap.create());
// System.out.println(inverse);

// Map<String,String> map = new HashMap<String,String>();
// map.put("1", "b");
// map.put("2","d");
// String mapJoinResult = Joiner.on(",").withKeyValueSeparator("=").join(map);
// System.out.println(mapJoinResult);
// Joiner joiner = Joiner.on(",");
// 下面报错
// System.out.println(joiner.join("hank",null,"kun"));
// 正常
// Joiner joiner1 = Joiner.on(",").skipNulls();
// System.out.println(joiner1.join("hank",null,"kun"));

// String test = " ,a,,b,";
// jdk正常模式
// System.out.println(test.split(",").length);
// System.out.println(Splitter.on(",").omitEmptyStrings().trimResults().split(test));

// HashCode hashCode = Hashing.md5().newHasher().putString("name", Charsets.UTF_8).hash();
// System.out.println(hashCode.hashCode());

// TypeToken<Function<Integer, String>> funToken = new TypeToken<Function<Integer, String>>() {};
//
// TypeToken<?> funResultToken = funToken.resolveType(Function.class.getTypeParameters()[1]);
// System.out.println(funResultToken.getType());

// 读写文件
// writeFile("first","hank is good");
// readFile("first");
// copyFile("first","second");

}

void writeFile(String name, String content) {
File file = new File(name);
try {
Files.write(content.getBytes(), file);
}
catch (IOException e) {
e.printStackTrace();
}
}

void readFile(String name) {
File file = new File(name);
System.out.println(Files.getNameWithoutExtension("first"));
System.out.println(Files.getFileExtension("first.txt"));
try {
List<String> strings = Files.readLines(file, Charsets.UTF_8);
System.out.println(strings);

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

void copyFile(String src, String dest) {
File srcFile = new File(src);
File destFile = new File(dest);
try {
Files.copy(srcFile, destFile);
}
catch (IOException e) {
e.printStackTrace();
}
}
}