Java 仅当bean作为方法参数存在时,Spring autowire
我正在使用Java 仅当bean作为方法参数存在时,Spring autowire,java,spring,spring-boot,Java,Spring,Spring Boot,我正在使用@ConditionalOnProperty创建文件压缩程序bean: @Bean @ConditionalOnProperty(prefix = "file.rollover.sink", name = "compress", matchIfMissing = true) public FileCompressor fileCompressor() { return new DefaultFileCompressor(...); } 我只想在存在的情况下自动连接FileCo
@ConditionalOnProperty
创建文件压缩程序
bean:
@Bean
@ConditionalOnProperty(prefix = "file.rollover.sink", name = "compress", matchIfMissing = true)
public FileCompressor fileCompressor() {
return new DefaultFileCompressor(...);
}
我只想在存在的情况下自动连接FileCompressor
bean,null
iffile.rollover.sink.compress=false
作为方法参数。
但如果我试着这样定义它:
@Bean
public RolloverTask rolloverTask(final IntervalCalculator intervalCalculator, final @Autowired(required = false) FileCompressor fileCompressor) {
return new RolloverTask(intervalCalculator, fileCompressor);
}
我得到以下错误:
Parameter 1 of method rolloverTask in com.example.FileRolloverSinkConfiguration required a bean of type 'com.example.compressor.FileCompressor' that could not be found.
- Bean method 'fileCompressor' in 'FileRolloverSinkConfiguration' not loaded because @ConditionalOnProperty (file.rollover.sink.compress) found different value in property 'compress'
如果不存在,我应该对autowire或passnull
进行哪些更改
--编辑--
我的解决方案:
private FileCompressor fileCompressor;
@Autowired(required = false)
public void setFileCompressor(final FileCompressor fileCompressor) {
this.fileCompressor = fileCompressor;
}
@Bean
public RolloverTask rolloverTask(final IntervalCalculator intervalCalculator) {
log.info("Creating a new rollover task with{} a file compressor", fileCompressor == null ? "out" : "");
return new RolloverTask(intervalCalculator, fileCompressor);
}
@Bean
@ConditionalOnProperty(prefix = "file.rollover.sink", name = "compress", matchIfMissing = true)
public FileCompressor fileCompressor() {
return new DefaultFileCompressor(...);
}
我认为您可以使用注释
@ConditionalOnBean
和@ConditionalOnMissingBean
我没有尝试代码,但应该是这样的:
@Bean
@ConditionalOnBean(FileCompressor.class)
public RolloverTask rolloverTask(final IntervalCalculator intervalCalculator, final FileCompressor fileCompressor) {
return new RolloverTask(intervalCalculator, fileCompressor);
}
及
如果没有
havingValue=
,则使用matchIfMissing=true
是没有意义的。因为若你们并没有一个属性,那个么bean就会被创建,若你们有一个具有任何值的属性,那个么bean就会被创建
您可以通过以下方式解决此问题:
@Autowired(required = false)
private FileCompressor fileCompressor;
@Bean
public RolloverTask rolloverTaskWithCompressor(final IntervalCalculator intervalCalculator, final FileCompressor fileCompressor) {
return new RolloverTask(intervalCalculator, fileCompressor);
}
或者对两个版本的RolloverTask
有不同的bean定义:
@Bean
@ConditionalOnProperty(prefix = "file.rollover.sink", name = "compress", havingValue = "no", matchIfMissing = false)
public RolloverTask rolloverTask(IntervalCalculator intervalCalculator) {
return new RolloverTask(intervalCalculator, null);
}
@Bean
@ConditionalOnProperty(prefix = "file.rollover.sink", name = "compress", havingValue = "yes", matchIfMissing = true)
public RolloverTask rolloverTaskWithCompressor(final IntervalCalculator intervalCalculator, final FileCompressor fileCompressor) {
return new RolloverTask(intervalCalculator, fileCompressor);
}
我对你的第一个建议采用了类似的解决方案,我不喜欢有两个定义,一个是属性为真,另一个是属性为假。我的bean定义比这个例子要复杂一些。。。我已经把我的解决方案编辑好了。
@Bean
@ConditionalOnProperty(prefix = "file.rollover.sink", name = "compress", havingValue = "no", matchIfMissing = false)
public RolloverTask rolloverTask(IntervalCalculator intervalCalculator) {
return new RolloverTask(intervalCalculator, null);
}
@Bean
@ConditionalOnProperty(prefix = "file.rollover.sink", name = "compress", havingValue = "yes", matchIfMissing = true)
public RolloverTask rolloverTaskWithCompressor(final IntervalCalculator intervalCalculator, final FileCompressor fileCompressor) {
return new RolloverTask(intervalCalculator, fileCompressor);
}