guava处理字符串与List之间，字符串与map之间的转换

来源：互联网发布：推荐算法的稀疏性问题编辑：程序博客网时间：2024/05/29 09:31
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 */@Testpublic 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 */@Testpublic 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 */@Testpublic 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 */@Testpublic 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 */@Testpublic 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 */@Testpublic 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 */@Testpublic 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 */@Testpublic 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 */@Testpublic 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);} }
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