titan.lightbatis.mapper.SpringBootBindUtil Maven / Gradle / Ivy
/**
*
*/
package titan.lightbatis.mapper;
import org.springframework.beans.MutablePropertyValues;
import org.springframework.beans.PropertyValues;
import org.springframework.core.env.Environment;
import org.springframework.core.env.PropertyResolver;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.util.Map;
/**
* @author [email protected]
*
*/
public class SpringBootBindUtil {
public static final IBind BIND;
static {
IBind bind;
try {
//boot2
Class.forName("org.springframework.boot.context.properties.bind.Binder");
bind = new SpringBoot2Bind();
} catch (Exception e) {
//boot1
bind = new SpringBoot1Bind();
}
BIND = bind;
}
public static T bind(Environment environment, Class targetClass, String prefix) {
return BIND.bind(environment, targetClass, prefix);
}
public interface IBind {
T bind(Environment environment, Class targetClass, String prefix);
}
/**
* 使用 Spring Boot 1.x 方式绑定
*/
public static class SpringBoot1Bind implements IBind {
@Override
public T bind(Environment environment, Class targetClass, String prefix) {
/**
为了方便以后直接依赖 Spring Boot 2.x 时不需要改动代码，这里也使用反射
try {
RelaxedPropertyResolver resolver = new RelaxedPropertyResolver(environment);
Map properties = resolver.getSubProperties("");
T target = targetClass.newInstance();
RelaxedDataBinder binder = new RelaxedDataBinder(target, prefix);
binder.bind(new MutablePropertyValues(properties));
return target;
} catch (Exception e) {
throw new RuntimeException(e);
}
下面是这段代码的反射实现
*/
try {
//反射提取配置信息
Class resolverClass = Class.forName("org.springframework.boot.bind.RelaxedPropertyResolver");
Constructor resolverConstructor = resolverClass.getDeclaredConstructor(PropertyResolver.class);
Method getSubPropertiesMethod = resolverClass.getDeclaredMethod("getSubProperties", String.class);
Object resolver = resolverConstructor.newInstance(environment);
Map properties = (Map) getSubPropertiesMethod.invoke(resolver, "");
//创建结果类
T target = targetClass.newInstance();
//反射使用 org.springframework.boot.bind.RelaxedDataBinder
Class binderClass = Class.forName("org.springframework.boot.bind.RelaxedDataBinder");
Constructor binderConstructor = binderClass.getDeclaredConstructor(Object.class, String.class);
Method bindMethod = binderClass.getMethod("bind", PropertyValues.class);
//创建 binder 并绑定数据
Object binder = binderConstructor.newInstance(target, prefix);
bindMethod.invoke(binder, new MutablePropertyValues(properties));
return target;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
/**
* 使用 Spring Boot 2.x 方式绑定
*/
public static class SpringBoot2Bind implements IBind {
@Override
public T bind(Environment environment, Class targetClass, String prefix) {
/**
由于不能同时依赖不同的两个版本，所以使用反射实现下面的代码
Binder binder = Binder.get(environment);
return binder.bind(prefix, targetClass).get();
下面是这两行代码的完全反射版本
*/
try {
Class bindClass = Class.forName("org.springframework.boot.context.properties.bind.Binder");
Method getMethod = bindClass.getDeclaredMethod("get", Environment.class);
Method bindMethod = bindClass.getDeclaredMethod("bind", String.class, Class.class);
Object bind = getMethod.invoke(null, environment);
Object bindResult = bindMethod.invoke(bind, prefix, targetClass);
Method resultGetMethod = bindResult.getClass().getDeclaredMethod("get");
Method isBoundMethod = bindResult.getClass().getDeclaredMethod("isBound");
if ((Boolean) isBoundMethod.invoke(bindResult)) {
return (T) resultGetMethod.invoke(bindResult);
}
return null;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}
}