如何编辑或更改 Spring 参数扩展？

Question

在application.yml中：

flyway:
  locations: classpath:/db/migration, classpath:/db/local
  placeholders:
    csvpath: ${user.dir}/src/main/resources/db/local

在 flyway 初始化脚本中：

LOAD DATA LOCAL INFILE '${csvpath}/data.csv'
INTO TABLE myscheama.t1 FIELDS TERMINATED BY ','
ENCLOSED BY '"' LINES TERMINATED BY '\n'
IGNORE 1 LINES;

${user.dir} 扩展到当前项目的路径（我想要的），但是在 Windows 框上扩展为路径分隔符“\”。当 Spring Boot 启动时，flyway 会立即执行，将扩展路径传递到我的数据库 (MySQL)，它将不接受路径名中的“\”。我如何才能强制使用“/”或在我的路径中使用正确的斜杠来使其正常工作？

Answer 1

我能够通过实施 EnvironmentPostProcessor 来解决这个问题：

将 META-INF/spring.factories 属性文件添加到 src/main/resources

# Environment Post Processor 
org.springframework.boot.env.EnvironmentPostProcessor = com.gitlab.ttubbs.myapp.PropertiesEnvironmentPostProcessor

添加实现：

package com.gitlab.ttubbs.myapp;

import java.util.Map;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.env.EnvironmentPostProcessor;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.MapPropertySource;
import org.springframework.core.env.MutablePropertySources;
import org.springframework.core.env.PropertySource;

public class PropertiesEnvironmentPostProcessor implements EnvironmentPostProcessor
{

    private static final String SYSTEM_PROPERTIES = "systemProperties";
    private static final String USER_DIR         = "user.dir";
    private static final char   BACKSLASH        = '\';
    private static final char   FORWARD_SLASH    = '/';

    @Override
    public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) {
        MutablePropertySources propertySources = environment.getPropertySources();
        Map<String, Object> systemProperties = getMapPropertySource(propertySources, SYSTEM_PROPERTIES);

        // Update ${user.dir} to use FORWARD_SLASH instead of BACKSLASH
        updateMapProperty(systemProperties, USER_DIR, environment.getProperty(USER_DIR).replace(BACKSLASH, FORWARD_SLASH));
    }

    private Map<String, Object> getMapPropertySource(MutablePropertySources propertySources, String sourceName) {
        if (propertySources.contains(sourceName)) {
            PropertySource<?> source = propertySources.get(sourceName);
            if (source instanceof MapPropertySource) {
                MapPropertySource target = (MapPropertySource) source;
                return target.getSource();
            }
        }

        return null;
    }

    private void updateMapProperty(Map<String, Object> target, String key, String value) {
        if(target != null) {
            target.put(key, value);
        }
    }
}

如何编辑或更改 Spring 参数扩展？

How to edit or alter Spring parameter expansion?

spring

flyway

spring-boot