guava处理字符串与List之间，字符串与map之间的转换<转>

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);
}

}