org.springframework.boot.context.FileEncodingApplicationListener Maven / Gradle / Ivy
/*
* Copyright 2012-2017 the original author or authors.
*
* Licensed 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
*
* https://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.
*/
package org.springframework.boot.context;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.core.Ordered;
import org.springframework.core.env.ConfigurableEnvironment;
/**
* An {@link ApplicationListener} that halts application startup if the system file
* encoding does not match an expected value set in the environment. By default has no
* effect, but if you set {@code spring.mandatory_file_encoding} (or some camelCase or
* UPPERCASE variant of that) to the name of a character encoding (e.g. "UTF-8") then this
* initializer throws an exception when the {@code file.encoding} System property does not
* equal it.
*
*
* The System property {@code file.encoding} is normally set by the JVM in response to the
* {@code LANG} or {@code LC_ALL} environment variables. It is used (along with other
* platform-dependent variables keyed off those environment variables) to encode JVM
* arguments as well as file names and paths. In most cases you can override the file
* encoding System property on the command line (with standard JVM features), but also
* consider setting the {@code LANG} environment variable to an explicit
* character-encoding value (e.g. "en_GB.UTF-8").
*
* @author Dave Syer
* @author Madhura Bhave
*/
public class FileEncodingApplicationListener
implements ApplicationListener, Ordered {
private static final Log logger = LogFactory
.getLog(FileEncodingApplicationListener.class);
@Override
public int getOrder() {
return Ordered.LOWEST_PRECEDENCE;
}
@Override
public void onApplicationEvent(ApplicationEnvironmentPreparedEvent event) {
ConfigurableEnvironment environment = event.getEnvironment();
if (!environment.containsProperty("spring.mandatory-file-encoding")) {
return;
}
String encoding = System.getProperty("file.encoding");
String desired = environment.getProperty("spring.mandatory-file-encoding");
if (encoding != null && !desired.equalsIgnoreCase(encoding)) {
logger.error("System property 'file.encoding' is currently '" + encoding
+ "'. It should be '" + desired
+ "' (as defined in 'spring.mandatoryFileEncoding').");
logger.error("Environment variable LANG is '" + System.getenv("LANG")
+ "'. You could use a locale setting that matches encoding='"
+ desired + "'.");
logger.error("Environment variable LC_ALL is '" + System.getenv("LC_ALL")
+ "'. You could use a locale setting that matches encoding='"
+ desired + "'.");
throw new IllegalStateException(
"The Java Virtual Machine has not been configured to use the "
+ "desired default character encoding (" + desired + ").");
}
}
}