/*******************************************************************************
* Copyright (c) 2005, 2014 springside.github.io
*
* Licensed under the Apache License, Version 2.0 (the "License");
*******************************************************************************/
package org.springside.examples.showcase.demos.utilities.string;
import static org.assertj.core.api.Assertions.*;
import java.util.List;
import java.util.Map;
import org.junit.Test;
import com.google.common.base.CaseFormat;
import com.google.common.base.Charsets;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.collect.Maps;
/**
* 演示 Guava的比Apache StringUtils更高级的Joiner和Spliter，Case Format转换
*
* @author calvin
*/
public class GuavaStringUtilsDemo {
/**
* Guava的高级版Joiner，
*/
@Test
public void joiner() {
// 忽略Null值。
String[] fantasyGenres = { "Space Opera", null, "Horror", "Magic realism", null, "Religion" };
String joined = Joiner.on(", ").skipNulls().join(fantasyGenres);
assertThat(joined).isEqualTo("Space Opera, Horror, Magic realism, Religion");
// 将Null值转换为特定字符串.
String[] fantasyGenres2 = { "Space Opera", null, "Horror", "Magic realism", null, "Religion" };
joined = Joiner.on(", ").useForNull("NULL!!!").join(fantasyGenres2);
assertThat(joined).isEqualTo("Space Opera, NULL!!!, Horror, Magic realism, NULL!!!, Religion");
// join Map类型
Map<Integer, String> map = Maps.newHashMap();
map.put(1, "Space Opera");
map.put(2, "Horror");
map.put(3, "Magic realism");
joined = Joiner.on(",").withKeyValueSeparator(":").join(map);
assertThat(joined).isEqualTo("1:Space Opera,2:Horror,3:Magic realism");
// append一个已存在的字符串
StringBuilder sb = new StringBuilder("Append StringBulder demo: ");
joined = Joiner.on(", ").skipNulls().appendTo(sb, fantasyGenres).toString();
assertThat(joined).isEqualTo("Append StringBulder demo: Space Opera, Horror, Magic realism, Religion");
// reuse joiner
Joiner joiner = Joiner.on(", ");
joiner.join(fantasyGenres);
joiner.join(fantasyGenres2);
}
/**
* Splitter有很多函数与Joiner一样，不一一演示
*/
@Test
public void splitter() {
// 去除逗号前后的空格
String input = "Space Opera,Horror, Magic realism,Religion";
List<String> result = Splitter.on(",").trimResults().splitToList(input);
assertThat(result).containsSequence("Space Opera", "Horror", "Magic realism", "Religion");
}
/**
* 好玩的CaseFormat转换，在spaceSize->space_size之间转换，比如数据库表名与Java类名，变量名之间的转换。
*/
@Test
public void caseFormatByGuava() {
String name = "SPACE_SIZE";
assertThat(CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.UPPER_CAMEL, name)).isEqualTo("SpaceSize");
assertThat(CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.LOWER_CAMEL, name)).isEqualTo("spaceSize");
assertThat(CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.LOWER_UNDERSCORE, name)).isEqualTo("space_size");
assertThat(CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.LOWER_HYPHEN, name)).isEqualTo("space-size");
}
@Test
public void otherUtils() {
// 直接getBytes, 无需catch UnsupportedEncodingException, JDK7 有相应的StandardCharsets
byte[] bytes = "foobarbaz".getBytes(Charsets.UTF_8);
}
}