guava处理字符串与List之间，字符串与map之间的转换

淩亂°似流年 2021-06-24 15:57 553阅读 0赞

import static org.junit.Assert.*;
    
    import java.util.List;
    import java.util.Map;
    
    import org.junit.Test;
    
    import com.google.common.base.Joiner;
    import com.google.common.base.Splitter;
    import com.google.common.collect.Lists;
    import com.google.common.collect.Maps;
    
    
    public class Guava {
    
    	/**
    	 * list转换为字符串
    	 */
    	@Test
    	public void joinTest(){
    	    List<String> names = Lists.newArrayList("John", "Jane", "Adam", "Tom");
    	    String result = Joiner.on(",").join(names);
    	 
    	    assertEquals(result, "John,Jane,Adam,Tom");
    	}
    
    
    	/**
    	 * map转换为字符串
    	 */
    	@Test
    	public void whenConvertMapToString_thenConverted() {
    	    Map<String, Integer> salary = Maps.newHashMap();
    	    salary.put("John", 1000);
    	    salary.put("Jane", 1500);
    	    String result = Joiner.on(" , ").withKeyValueSeparator(" = ")
    	                                    .join(salary);
    	    System.out.println(result);
    	}
    	
    	/**
    	 * list转String，跳过null
    	 */
    	@Test
    	public void whenConvertListToStringAndSkipNull_thenConverted() {
    	    List<String> names = Lists.newArrayList("John", null, "Jane", "Adam", "Tom");
    	    String result = Joiner.on(",").skipNulls().join(names);
    	    System.out.println(result);
    	    assertEquals(result, "John,Jane,Adam,Tom");
    	}
    
    	/**
    	 * list转String，将null变成其他值
    	 */
    	@Test
    	public void whenUseForNull_thenUsed() {
    	    List<String> names = Lists.newArrayList("John", null, "Jane", "Adam", "Tom");
    	    String result = Joiner.on(",").useForNull("nameless").join(names);
    	    System.out.println(result);
    	    assertEquals(result, "John,nameless,Jane,Adam,Tom");
    	}
    	
    	/**
    	 * String to List
    	 */
    	@Test
    	public void whenCreateListFromString_thenCreated() {
    	    String input = "apple - banana - orange";
    	    List<String> result = Splitter.on("-").trimResults().splitToList(input);
    	    System.out.println(result);
    	    //assertThat(result, contains("apple", "banana", "orange"));
    	}
    
    	/**
    	 * String to Map
    	 */
    	@Test
    	public void whenCreateMapFromString_thenCreated() {
    	    String input = "John=first,Adam=second";
    	    Map<String, String> result = Splitter.on(",")
    	                                         .withKeyValueSeparator("=")
    	                                         .split(input);
    	 
    	    assertEquals("first", result.get("John"));
    	    assertEquals("second", result.get("Adam"));
    	}
    
    	/**
    	 * 多个字符进行分割
    	 */
    	@Test
    	public void whenSplitStringOnMultipleSeparator_thenSplit() {
    	    String input = "apple.banana,,orange,,.";
    	    List<String> result = Splitter.onPattern("[.|,]")
    	                                  .omitEmptyStrings()
    	                                  .splitToList(input);
    	    System.out.println(result);
    	}
    	
    	/**
    	 * 每隔多少字符进行分割
    	 */
    	@Test
    	public void whenSplitStringOnSpecificLength_thenSplit() {
    	    String input = "Hello world";
    	    List<String> result = Splitter.fixedLength(3).splitToList(input);
    	    System.out.println(result);
    	}
    
    	/**
    	 * 限制分割多少字后停止
    	 */
    	@Test
    	public void whenLimitSplitting_thenLimited() {
    	    String input = "a,b,c,d,e";
    	    List<String> result = Splitter.on(",")
    	                                  .limit(4)
    	                                  .splitToList(input);
    	 
    	    assertEquals(4, result.size());
    	    System.out.println(result);
    	}
     
    
    
    
    }