Guava入门第二章(Splitter)

Splitter详细介绍

---

package com.lvshihao.guava;

import com.google.common.base.Splitter;
import org.junit.Test;
import java.util.List;
import java.util.Map;
import java.util.regex.Pattern;

import static org.hamcrest.core.IsEqual.equalTo;
import static org.hamcrest.core.IsNull.notNullValue;
import static org.junit.Assert.assertThat;

/**
 *@author: LVSHIHAO
 *@description: GUAVA Splitter detailed introduction
 */
public class SplitterTest {

    @Test
    public void testSplitOnSplit(){
        List<String> result = Splitter.on("|").splitToList("hello|lvshihao");
        assertThat(result,notNullValue());
        assertThat(result.size(),equalTo(2));
        assertThat(result.get(0),equalTo("hello"));
        assertThat(result.get(1),equalTo("lvshihao"));
    }

    @Test
    public void testSplitOnSplitOmitEmpty(){
        /**
         * omitEmptyStrings()忽略掉空的字符串  ignore Empty Strings
         */
        List<String> result = Splitter.on("|").omitEmptyStrings().splitToList("hello|lvshihao|||");
        assertThat(result,notNullValue());
        assertThat(result.size(),equalTo(2));
        assertThat(result.get(0),equalTo("hello"));
        assertThat(result.get(1),equalTo("lvshihao"));
    }

    @Test
    public void testSplitOnSplitOmitEmptyTrimResult(){
        /**
         * trimResults()去除字符串前后的空格  remove Strings first last space
         */
        List<String> result = Splitter.on("|").trimResults().omitEmptyStrings().splitToList("hello  |  lvshihao  |||");
        assertThat(result,notNullValue());
        assertThat(result.size(),equalTo(2));
        assertThat(result.get(0),equalTo("hello"));
        assertThat(result.get(1),equalTo("lvshihao"));
    }

    @Test
    public void testSplitFixLength(){
        /**
         * fixedLength()以固定长度截取字符串  with fixed length split strings
         */
        List<String> result = Splitter.fixedLength(4).splitToList("aaaabbbbccccdddd");
        assertThat(result,notNullValue());
        assertThat(result.size(),equalTo(4));
        assertThat(result.get(0),equalTo("aaaa"));
        assertThat(result.get(1),equalTo("bbbb"));
        assertThat(result.get(2),equalTo("cccc"));
        assertThat(result.get(3),equalTo("dddd"));
    }

    @Test
    public void testSplitOnSplitLimit(){
        /**
         * limit() 限制截取几个元素 limit split some element
         */
        List<String> result = Splitter.on("#").limit(4).splitToList("hello#lvshihao#lvbu#java#scala");
        assertThat(result,notNullValue());
        assertThat(result.size(),equalTo(4));
        assertThat(result.get(0),equalTo("hello"));
        assertThat(result.get(1),equalTo("lvshihao"));
        assertThat(result.get(2),equalTo("lvbu"));
        assertThat(result.get(3),equalTo("java#scala"));
    }

    @Test
    public void testSplitOnPatternString(){
        /**
         * onPattern() 使用正则表达式进行切分 use Regular expression conduct split
         */
        List<String> result = Splitter.onPattern("\|").trimResults().omitEmptyStrings().splitToList("hello  |  lvshihao  |||");
        assertThat(result,notNullValue());
        assertThat(result.size(),equalTo(2));
        assertThat(result.get(0),equalTo("hello"));
        assertThat(result.get(1),equalTo("lvshihao"));
    }

    @Test
    public void testSplitOnPattern(){
        /**
         * on() 也可以在on里面使用正则表达式    possible in on inside Regular expression
         */
        List<String> result = Splitter.on(Pattern.compile("\|")).trimResults().omitEmptyStrings().splitToList("hello  |  lvshihao  |||");
        assertThat(result,notNullValue());
        assertThat(result.size(),equalTo(2));
        assertThat(result.get(0),equalTo("hello"));
        assertThat(result.get(1),equalTo("lvshihao"));
    }

    @Test
    public void testSplitOnSplitToMap(){
        /**
         * withKeyValueSeparator() 键值对分割符号，代表这是个键值对类型的  key value pair split sign,represent this is key value type
         */
        Map<String, String> result = Splitter.on(Pattern.compile("\|")).trimResults().omitEmptyStrings().withKeyValueSeparator(":").split("name:lvshihao  |  age:18  |||");
        assertThat(result,notNullValue());
        assertThat(result.size(),equalTo(2));
        assertThat(result.get("name"),equalTo("lvshihao"));
        assertThat(result.get("age"),equalTo("18"));
    }


}