解决-Spring boot: 加载jar包外部json配置文件时，报错"File not found"

描述

打包时把resource/activity-config.json文件分离到jar包同级目录下config/activity-config.json后，通过@Value("classpath:activity-config.json") private Resource activityConfigRes;方式，获取不到json里面的内容。

解决办法：不用注解，改用System.getProperty("user.dir") + "/config/activity-config.json";这种方式读取配置文件中的内容。

            String filePath = System.getProperty("user.dir")
                    + "/config/activity-config.json";
            InputStream in = new BufferedInputStream(new FileInputStream(filePath));
            String areaData =  IOUtils.toString(in, Charset.forName("UTF-8"));
            ObjectMapper mapper = new ObjectMapper();
            ActivityConfig config = mapper.readValue(areaData, ActivityConfig.class);

如何加载jar包外部json配置文件实现步骤

第一步

在resource目录下创建json配置文件activity-config.json

第二步

打包时从jar包中分离出配置文件到与jar包同级的文件夹config下。

    <build>
        <finalName>${project.artifactId}</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <configuration>
                    <!--跳过测试-->
                    <skipTests>true</skipTests>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>2.6</version>
                <configuration>
                    <archive>
                        <manifest>
                            <addClasspath>true</addClasspath>
                            <classpathPrefix>lib/</classpathPrefix>
                            <!--指定启动类-->
                            <mainClass>**.**.Application</mainClass>
                        </manifest>
                    </archive>
                    <!--指定classes目录-->
                    <!--<classesDirectory>src/main/java</classesDirectory>-->
                    <outputDirectory>${project.package.directory}/${project.artifactId}</outputDirectory>
                    <!--排除classes目录下不需要打包的文件-->
                    <excludes>
                        <!--<exclude>META-INF/**</exclude>-->
                        <exclude>application.properties</exclude>
                        <exclude>*.json</exclude>  
                        <exclude>logback-spring.xml</exclude>
                    </excludes>
                </configuration>
            </plugin>

            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <version>2.6</version>
                <executions>
                    <execution>
                        <id>copy-dependencies</id>
                        <phase>package</phase>
                        <goals>
                            <goal>copy-dependencies</goal>
                        </goals>
                        <configuration>
                            <includeScope>compile</includeScope>
                            <!--复制依赖jar到指令目录-->
                            <outputDirectory>${project.package.directory}/${project.artifactId}/lib</outputDirectory>
                        </configuration>
                    </execution>
                </executions>

            </plugin>
            <!--复制资源文件到指定目录-->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-resources-plugin</artifactId>
                <version>2.6</version>
                <executions>
                    <execution>
                        <id>copy-resources</id>
                        <phase>package</phase>
                        <goals>
                            <goal>copy-resources</goal>
                        </goals>
                        <configuration>
                            <outputDirectory>${project.package.directory}/${project.artifactId}/config/</outputDirectory>
                            <resources>
                                <resource>
                                    <!--资源文件的目录-->
                                    <directory>src/main/resources/</directory>
                                </resource>
                            </resources>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

第三步

读取配置文件内容，转换成对象

        try {
            String filePath = System.getProperty("user.dir")
                    + "/config/activity-config.json";
            InputStream in = new BufferedInputStream(new FileInputStream(filePath));
            String areaData =  IOUtils.toString(in, Charset.forName("UTF-8"));
            logger.info("读取活动配置文件：" + areaData);
            ObjectMapper mapper = new ObjectMapper();
            ActivityConfig config = mapper.readValue(areaData, ActivityConfig.class);
        } catch (Exception e) {
            e.printStackTrace();
        }

如果要用到IOUtils，需要在pom文件中导入下面的配置。

        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.6</version>
        </dependency>