SpringBoot 官方文档示例：(36)自定义校验器对application.properties中配置的属性进行校验

一、自定义配置属性类：

package cn.edu.tju.config;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

@Component
@ConfigurationProperties(prefix = "my.test")
public class EndPointProperty {


    private String host;

    private Integer port = 8080;

    public String getHost() {
        return this.host;
    }

    public void setHost(String host) {
        this.host = host;
    }

    public Integer getPort() {
        return this.port;
    }

    public void setPort(Integer port) {
        this.port = port;
    }

}

二、自定义属性校验器

package cn.edu.tju.config;

import java.util.regex.Pattern;

import org.springframework.validation.Errors;
import org.springframework.validation.ValidationUtils;
import org.springframework.validation.Validator;

public class MyPropertyValidator implements Validator {

    final Pattern pattern = Pattern.compile("^(?:[0-9]{1,3}\.){3}[0-9]{1,3}$");

    @Override
    public boolean supports(Class type) {
        return type == EndPointProperty.class;
    }

    @Override
    public void validate(Object o, Errors errors) {
        ValidationUtils.rejectIfEmpty(errors, "host", "host.empty");
        ValidationUtils.rejectIfEmpty(errors, "port", "port.empty");
        EndPointProperty properties = (EndPointProperty) o;
        if (properties.getHost() != null
                && !this.pattern.matcher(properties.getHost()).matches()) {
            errors.rejectValue("host", "Invalid host");
        }
    }

}

三、配置属性校验器bean

    @Bean
    public static Validator configurationPropertiesValidator() {
        return new MyPropertyValidator();
    }

四、在application.properties中进行配置

my.test.host=139.198.99.99
my.test.port=9988

如果违反校验规则，

my.test.host=139.198.9999.9999
my.test.port=9988

则程序启动时直接报错