输入一个字符串，打印出该字符串中字符的所有排列。例如：输入字符串abc，则打印出由字符a、b、c所能排列出来的所有字符串abc、acb、bac、bca、cab、cba。
这里需要注意的是防止重复的问题，所以需要使用Set来进行过滤，一个for循环就可以搞定,具体代码如下：
package com.example.demo.upload.controller;
import java.util.HashSet;
import java.util.Set;
public class test {
static Set set=new HashSet<>();
public static void main(String[] args) {
String test="abcde";
permutation(test);
for(String str:set){
System.out.println(str);
}
}
public static void permutation(String test){
if (test==null)
return;
permutationtest(test.toCharArray(),0);
}
public static void permutationtest(char[] chars,int pos){
if (pos==chars.length-1){
if (!set.contains(chars.toString())){
set.add(String.valueOf(chars));
}
}
for (int i=pos;i
返回结果如下：
D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301binjava.exe "-javaagent:C:Program FilesJetBrainsIntelliJ IDEA 2018.2.5libidea_rt.jar=53214:C:Program FilesJetBrainsIntelliJ IDEA 2018.2.5bin" -Dfile.encoding=UTF-8 -classpath D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibcharsets.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibdeploy.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibextaccess-bridge-64.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibextcldrdata.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibextdnsns.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibextjaccess.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibextjfxrt.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibextlocaledata.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibextnashorn.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibextsunec.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibextsunjce_provider.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibextsunmscapi.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibextsunpkcs11.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibextzipfs.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibjavaws.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibjce.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibjfr.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibjfxswt.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibjsse.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibmanagement-agent.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibplugin.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibresources.jar;D:sofewarejdk1.8JDK1.8Javajdk1.8.0_301jrelibrt.jar;D:projectfenpianFragmentUpload-mastertargetclasses;C:Usersligx1.m2repositoryorgspringframeworkbootspring-boot-starter-thymeleaf2.3.1.RELEASEspring-boot-starter-thymeleaf-2.3.1.RELEASE.jar;C:Usersligx1.m2repositoryorgspringframeworkbootspring-boot-starter2.3.1.RELEASEspring-boot-starter-2.3.1.RELEASE.jar;C:Usersligx1.m2repositoryorgspringframeworkbootspring-boot2.3.1.RELEASEspring-boot-2.3.1.RELEASE.jar;C:Usersligx1.m2repositoryorgspringframeworkbootspring-boot-starter-logging2.3.1.RELEASEspring-boot-starter-logging-2.3.1.RELEASE.jar;C:Usersligx1.m2repositorychqoslogbacklogback-classic1.2.3logback-classic-1.2.3.jar;C:Usersligx1.m2repositorychqoslogbacklogback-core1.2.3logback-core-1.2.3.jar;C:Usersligx1.m2repositoryorgapachelogginglog4jlog4j-to-slf4j2.13.3log4j-to-slf4j-2.13.3.jar;C:Usersligx1.m2repositoryorgapachelogginglog4jlog4j-api2.13.3log4j-api-2.13.3.jar;C:Usersligx1.m2repositoryorgslf4jjul-to-slf4j1.7.30jul-to-slf4j-1.7.30.jar;C:Usersligx1.m2repositoryjakartaannotationjakarta.annotation-api1.3.5jakarta.annotation-api-1.3.5.jar;C:Usersligx1.m2repositoryorgyamlsnakeyaml1.26snakeyaml-1.26.jar;C:Usersligx1.m2repositoryorgthymeleafthymeleaf-spring53.0.11.RELEASEthymeleaf-spring5-3.0.11.RELEASE.jar;C:Usersligx1.m2repositoryorgthymeleafthymeleaf3.0.11.RELEASEthymeleaf-3.0.11.RELEASE.jar;C:Usersligx1.m2repositoryorgattoparserattoparser2.0.5.RELEASEattoparser-2.0.5.RELEASE.jar;C:Usersligx1.m2repositoryorgunbescapeunbescape1.1.6.RELEASEunbescape-1.1.6.RELEASE.jar;C:Usersligx1.m2repositoryorgslf4jslf4j-api1.7.30slf4j-api-1.7.30.jar;C:Usersligx1.m2repositoryorgthymeleafextrasthymeleaf-extras-java8time3.0.4.RELEASEthymeleaf-extras-java8time-3.0.4.RELEASE.jar;C:Usersligx1.m2repositoryorgspringframeworkbootspring-boot-starter-web2.3.1.RELEASEspring-boot-starter-web-2.3.1.RELEASE.jar;C:Usersligx1.m2repositoryorgspringframeworkbootspring-boot-starter-json2.3.1.RELEASEspring-boot-starter-json-2.3.1.RELEASE.jar;C:Usersligx1.m2repositorycomfasterxmljacksoncorejackson-databind2.11.0jackson-databind-2.11.0.jar;C:Usersligx1.m2repositorycomfasterxmljacksoncorejackson-annotations2.11.0jackson-annotations-2.11.0.jar;C:Usersligx1.m2repositorycomfasterxmljacksoncorejackson-core2.11.0jackson-core-2.11.0.jar;C:Usersligx1.m2repositorycomfasterxmljacksondatatypejackson-datatype-jdk82.11.0jackson-datatype-jdk8-2.11.0.jar;C:Usersligx1.m2repositorycomfasterxmljacksondatatypejackson-datatype-jsr3102.11.0jackson-datatype-jsr310-2.11.0.jar;C:Usersligx1.m2repositorycomfasterxmljacksonmodulejackson-module-parameter-names2.11.0jackson-module-parameter-names-2.11.0.jar;C:Usersligx1.m2repositoryorgspringframeworkbootspring-boot-starter-tomcat2.3.1.RELEASEspring-boot-starter-tomcat-2.3.1.RELEASE.jar;C:Usersligx1.m2repositoryorgapachetomcatembedtomcat-embed-core9.0.36tomcat-embed-core-9.0.36.jar;C:Usersligx1.m2repositoryorgglassfishjakarta.el3.0.3jakarta.el-3.0.3.jar;C:Usersligx1.m2repositoryorgapachetomcatembedtomcat-embed-websocket9.0.36tomcat-embed-websocket-9.0.36.jar;C:Usersligx1.m2repositoryorgspringframeworkspring-web5.2.7.RELEASEspring-web-5.2.7.RELEASE.jar;C:Usersligx1.m2repositoryorgspringframeworkspring-beans5.2.7.RELEASEspring-beans-5.2.7.RELEASE.jar;C:Usersligx1.m2repositoryorgspringframeworkspring-webmvc5.2.7.RELEASEspring-webmvc-5.2.7.RELEASE.jar;C:Usersligx1.m2repositoryorgspringframeworkspring-aop5.2.7.RELEASEspring-aop-5.2.7.RELEASE.jar;C:Usersligx1.m2repositoryorgspringframeworkspring-context5.2.7.RELEASEspring-context-5.2.7.RELEASE.jar;C:Usersligx1.m2repositoryorgspringframeworkspring-expression5.2.7.RELEASEspring-expression-5.2.7.RELEASE.jar;C:Usersligx1.m2repositoryorgspringframeworkspring-core5.2.7.RELEASEspring-core-5.2.7.RELEASE.jar;C:Usersligx1.m2repositoryorgspringframeworkspring-jcl5.2.7.RELEASEspring-jcl-5.2.7.RELEASE.jar;C:Usersligx1.m2repositoryorgprojectlomboklombok1.18.12lombok-1.18.12.jar;C:Usersligx1.m2repositorycommons-iocommons-io2.4commons-io-2.4.jar;C:Usersligx1.m2repositorycommons-fileuploadcommons-fileupload1.3.3commons-fileupload-1.3.3.jar;C:Usersligx1.m2repositorymysqlmysql-connector-java8.0.22mysql-connector-java-8.0.22.jar;C:Usersligx1.m2repositorycombaomidoumybatis-plus-boot-starter3.3.2mybatis-plus-boot-starter-3.3.2.jar;C:Usersligx1.m2repositorycombaomidoumybatis-plus3.3.2mybatis-plus-3.3.2.jar;C:Usersligx1.m2repositorycombaomidoumybatis-plus-extension3.3.2mybatis-plus-extension-3.3.2.jar;C:Usersligx1.m2repositorycombaomidoumybatis-plus-core3.3.2mybatis-plus-core-3.3.2.jar;C:Usersligx1.m2repositorycombaomidoumybatis-plus-annotation3.3.2mybatis-plus-annotation-3.3.2.jar;C:Usersligx1.m2repositorycomgithubjsqlparserjsqlparser3.1jsqlparser-3.1.jar;C:Usersligx1.m2repositoryorgmybatismybatis3.5.4mybatis-3.5.4.jar;C:Usersligx1.m2repositoryorgmybatismybatis-spring2.0.4mybatis-spring-2.0.4.jar;C:Usersligx1.m2repositoryorgspringframeworkbootspring-boot-autoconfigure2.3.1.RELEASEspring-boot-autoconfigure-2.3.1.RELEASE.jar;C:Usersligx1.m2repositoryorgspringframeworkbootspring-boot-starter-jdbc2.3.1.RELEASEspring-boot-starter-jdbc-2.3.1.RELEASE.jar;C:Usersligx1.m2repositorycomzaxxerHikariCP3.4.5HikariCP-3.4.5.jar;C:Usersligx1.m2repositoryorgspringframeworkspring-jdbc5.2.7.RELEASEspring-jdbc-5.2.7.RELEASE.jar;C:Usersligx1.m2repositoryorgspringframeworkspring-tx5.2.7.RELEASEspring-tx-5.2.7.RELEASE.jar com.example.demo.upload.controller.test
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Process finished with exit code 0
