详解MyBatis自定义Plugin插件

// ExamplePlugin.java
@Intercepts({@Signature(
 type= Executor.class,
 method = "update",
 args = {MappedStatement.class,Object.class},
 @Signature(
 　type = Executor.class, //必须为上面所支持的类
  method = "query", //类中支持的方法，可从源码中查看支持哪些方法
  args = {MappedStatement.class, Object.class , RowBounds.class, ResultHandler.class})}) //对应的参数Class,也可从源码中查看
public class ExamplePlugin implements Interceptor {
 public Object intercept(Invocation invocation) throws Throwable {
 Object[] queryArgs = invocation.getArgs();
  MappedStatement mappedStatement = (MappedStatement) queryArgs[0];
  Object parameter = queryArgs[1];
  BoundSql boundSql = mappedStatement.getBoundSql(parameter);
  String sql = boundSql.getSql();//获取到SQL ，可以进行调整
  String name = invocation.getMethod().getName();
  queryArgs[1] = 2; //可以修改参数内容
  System.err.println("拦截的方法名是：" + name);
  return invocation.proceed();
 }
 public Object plugin(Object target) {
  return Plugin.wrap(target, this);
 }
 public void setProperties(Properties properties) {
 }
}

<!-- mybatis-config.xml -->
<plugins>
 <plugin interceptor="org.mybatis.example.ExamplePlugin">
  <property name="someProperty" value="100"/>
 </plugin>
</plugins>