错误日志:Too many connections"

Question

这个错误，我查了好久！我先后改了mysql的最大连接数（从150该到了1000）；也没有解决这个问题？连接池用的是druid;又说是我没有关闭connections;但是我确实close了；

这是dao层简单代码：
public class esp8266Dao {

private DruidDataSource dataSource;
private ThreadLocal<Connection> threadLocal=new ThreadLocal<Connection>();

public esp8266Dao(DruidDataSource dataSource){
    this.dataSource=dataSource;
}

public synchronized Connection getConnection(){
    try {
        Connection connection = dataSource.getConnection();
        threadLocal.set(connection);
    } catch (SQLException throwables) {
        throwables.printStackTrace();
    }
    return threadLocal.get();
}

public String getState() throws SQLException {
    String station="close";
    Connection connection = getConnection();
    Statement statement = connection.createStatement();
    ResultSet resultSet=null;
    try {
        String sql="select * from esp8266";
        resultSet = statement.executeQuery(sql);
        while (resultSet.next()){
            station = resultSet.getString("esp8266Station");
        }
    }catch (Exception exception){
        exception.printStackTrace();
    }finally {
        if(resultSet != null){
            resultSet.close();
        }
        if(statement != null){
            statement.close();
        }
        if(connection != null){
            connection.close();
        }
    }
    return station;
}

这是错误提示：
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection, message from server: "Too many connections"

    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
    at com.mysql.jdbc.Util.getInstance(Util.java:383)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1023)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:997)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:983)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1111)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2494)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2527)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2309)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
    at sun.reflect.GeneratedConstructorAccessor16.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:419)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:344)
    at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1461)
    at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1525)
    at com.alibaba.druid.pool.DruidDataSource.init(DruidDataSource.java:734)
    at sun.reflect.GeneratedMethodAccessor64.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeCustomInitMethod(AbstractAutowireCapableBeanFactory.java:1702)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1641)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1570)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:539)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:755)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
    at com.LingBuJianKaiFa.controller.esp8266.get(esp8266.java:19)
    at sun.reflect.GeneratedMethodAccessor65.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:776)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:705)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)

Answer 1

搞定了，试了好多方法