springboot实现验证码校验demo

springboot实现验证码生成与校验功能。前端使用bootstrap，实现输入验证，一个非常不错的demo。

/*
Licensed to the Apache Software Foundation （ASF） under one
or more contributor license agreements.  See the NOTICE file
distributed with this work for additional information
regarding copyright ownership.  The ASF licenses this file
to you under the Apache License Version 2.0 （the
“License“）; you may not use this file except in compliance
with the License.  You may obtain a copy of the License at

  http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing
software distributed under the License is distributed on an
“AS IS“ BASIS WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND either express or implied.  See the License for the
specific language governing permissions and limitations
under the License.
*/

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.URL;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;
import java.util.Properties;

public class MavenWrapperDownloader {

    /**
     * Default URL to download the maven-wrapper.jar from if no ‘downloadUrl‘ is provided.
     */
    private static final String DEFAULT_DOWNLOAD_URL =
            “https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.4.2/maven-wrapper-0.4.2.jar“;

    /**
     * Path to the maven-wrapper.properties file which might contain a downloadUrl property to
     * use instead of the default one.
     */
    private static final String MAVEN_WRAPPER_PROPERTIES_PATH =
            “.mvn/wrapper/maven-wrapper.properties“;

    /**
     * Path where the maven-wrapper.jar will be saved to.
     */
    private static final String MAVEN_WRAPPER_JAR_PATH =
            “.mvn/wrapper/maven-wrapper.jar“;

    /**
     * Name of the property which should be used to override the default download url for the wrapper.
     */
    private static final String PROPERTY_NAME_WRAPPER_URL = “wrapperUrl“;

    public static void main（String args[]） {
        System.out.println（“- Downloader started“）;
        File baseDirectory = new File（args[0]）;
        System.out.println（“- Using base directory: “ + baseDirectory.getAbsolutePath（））;

        // If the maven-wrapper.properties exists read it and check if it contains a custom
        // wrapperUrl parameter.
        File mavenWrapperPropertyFile = new File（baseDirectory MAVEN_WRAPPER_PROPERTIES_PATH）;
        String url = DEFAULT_DOWNLOAD_URL;
        if （mavenWrapperPropertyFile.exists（）） {
            FileInputStream mavenWrapperPropertyFileInputStream = null;
            try {
                mavenWrapperPropertyFileInputStream = new FileInputStream（mavenWrapperPropertyFile）;
                Properties mavenWrapperProperties = new Properties（）;
                mavenWrapperProperties.load（mavenWrapperPropertyFileInputStream）;
                url = mavenWrapperProperties.getProperty（PROPERTY_NAME_WRAPPER_URL url）;
            } catch （IOException e） {
                Syste

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----
     目录           0  2019-04-18 09:44  springboot-code\
     文件         277  2019-03-05 09:33  springboot-code\.gitignore
     目录           0  2019-04-23 14:11  springboot-code\.idea\
     文件         657  2019-03-05 09:34  springboot-code\.idea\compiler.xml
     文件         177  2019-03-05 09:34  springboot-code\.idea\encodings.xml
     目录           0  2019-03-05 09:33  springboot-code\.idea\inspectionProfiles\
     文件        1444  2019-03-05 09:33  springboot-code\.idea\inspectionProfiles\Project_Default.xml
     目录           0  2019-03-05 10:57  springboot-code\.idea\libraries\
     文件         640  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__ch_qos_logback_logback_classic_1_2_3.xml
     文件         619  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__ch_qos_logback_logback_core_1_2_3.xml
     文件         594  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__com_fasterxml_classmate_1_4_0.xml
     文件         716  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__com_fasterxml_jackson_core_jackson_annotations_2_9_0.xml
     文件         667  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__com_fasterxml_jackson_core_jackson_core_2_9_8.xml
     文件         695  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__com_fasterxml_jackson_core_jackson_databind_2_9_8.xml
     文件         746  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__com_fasterxml_jackson_datatype_jackson_datatype_jdk8_2_9_8.xml
     文件         760  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__com_fasterxml_jackson_datatype_jackson_datatype_jsr310_2_9_8.xml
     文件         801  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__com_fasterxml_jackson_module_jackson_module_parameter_names_2_9_8.xml
     文件         600  2019-03-05 10:57  springboot-code\.idea\libraries\Maven__com_github_penggle_kaptcha_2_3_2.xml
     文件         618  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__com_jayway_jsonpath_json_path_2_4_0.xml
     文件         596  2019-03-05 10:57  springboot-code\.idea\libraries\Maven__com_jhlabs_filters_2_0_235_1.xml
     文件         772  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__com_vaadin_external_google_android_json_0_0_20131108_vaadin1.xml
     文件         683  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__javax_annotation_javax_annotation_api_1_3_2.xml
     文件         650  2019-03-05 10:57  springboot-code\.idea\libraries\Maven__javax_servlet_javax_servlet_api_4_0_1.xml
     文件         683  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__javax_validation_validation_api_2_0_1_Final.xml
     文件         527  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__junit_junit_4_12.xml
     文件         608  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__net_bytebuddy_byte_buddy_1_9_10.xml
     文件         650  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__net_bytebuddy_byte_buddy_agent_1_9_10.xml
     文件         614  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__net_minidev_accessors_smart_1_2.xml
     文件         579  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__net_minidev_json_smart_2_3.xml
     文件         645  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__org_apache_logging_log4j_log4j_api_2_11_2.xml
     文件         680  2019-03-05 09:34  springboot-code\.idea\libraries\Maven__org_apache_logging_log4j_log4j_to_slf4j_2_11_2.xml
............此处省略139个文件信息