cn.mybatis.mp.routing.datasource.RoutingDataSourceSpringInterceptor Maven / Gradle / Ivy
package cn.mybatis.mp.routing.datasource;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.DefaultParameterNameDiscoverer;
import org.springframework.core.ParameterNameDiscoverer;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.util.StringUtils;
import java.lang.reflect.Method;
import java.util.Objects;
/**
* 基于spring aopalliance的方法拦截器
*/
public class RoutingDataSourceSpringInterceptor implements MethodInterceptor {
/**
* 参数名解析器，用于获取参数名
*/
private static final ParameterNameDiscoverer localVariableTable = new DefaultParameterNameDiscoverer();
private static final ExpressionParser parser = new SpelExpressionParser();
private final Logger logger = LoggerFactory.getLogger(RoutingDataSourceSpringInterceptor.class);
@Autowired(required = false)
private RoutingDataSourceSwitchContext routingDataSourceSwitchContext;
public static void main(String[] args) {
String key = "{'slave-'+(#i % 2)}";
StandardEvaluationContext context = new StandardEvaluationContext();
context.setVariable("i", 1);
String str = parser.parseExpression(key.substring(1, key.length() - 1)).getValue(context, String.class);
System.out.println(str);
}
@Override
public Object invoke(MethodInvocation invocation) throws Throwable {
Method method = invocation.getMethod();
String dSKey = null;
String currentDSKey = DataSourceHolder.getCurrent();
if (method.isAnnotationPresent(DS.class)) {
DS ds = method.getAnnotation(DS.class);
dSKey = ds.value();
} else if (method.getDeclaringClass().isAnnotationPresent(DS.class)) {
DS ds = method.getDeclaringClass().getAnnotation(DS.class);
dSKey = ds.value();
}
dSKey = parseDSKey(dSKey, method, invocation.getArguments());
if (dSKey == null || dSKey.equals(currentDSKey)) {
//和当前一样 没必须切换
return invocation.proceed();
}
logger.debug(">>>>>>>>> {} 数据源切至：{}", method, dSKey);
DataSourceHolder.add(dSKey);
try {
return invocation.proceed();
} finally {
DataSourceHolder.remove();
dSKey = DataSourceHolder.getCurrent();
if (dSKey != null) {
logger.debug("<<<<<<<<< {} 数据源切回至：{}", method, dSKey);
}
}
}
private String parseDSKey(String key, Method method, Object[] args) {
if (Objects.isNull(key) || !StringUtils.hasText(key)) {
return null;
}
key = key.trim();
if (key.startsWith("{") && key.endsWith("}")) {
StandardEvaluationContext context = new StandardEvaluationContext();
//填充spEL的上下文对象
if (Objects.nonNull(args) && args.length > 0) {
String[] parameterNames = localVariableTable.getParameterNames(method);
for (int i = 0; i < parameterNames.length; i++) {
context.setVariable(parameterNames[i], args[i]);
}
}
if (Objects.nonNull(routingDataSourceSwitchContext)) {
context.setVariable("context", routingDataSourceSwitchContext.getVariables());
}
return parser.parseExpression(key).getValue(context, String.class);
}
return key;
}
}