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An JDBC datasource implementation.
/*
* Copyright 1999-2018 Alibaba Group Holding Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.alibaba.druid.support.http;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.management.MBeanServerConnection;
import javax.management.ObjectName;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXServiceURL;
import javax.servlet.ServletException;
import com.alibaba.druid.stat.DruidStatService;
import com.alibaba.druid.support.logging.Log;
import com.alibaba.druid.support.logging.LogFactory;
/**
* 注意：避免直接调用Druid相关对象例如DruidDataSource等，相关调用要到DruidStatManagerFacade里用反射实现
*
* @author sandzhang[[email protected]]
*/
public class StatViewServlet extends ResourceServlet {
private final static Log LOG = LogFactory.getLog(StatViewServlet.class);
private static final long serialVersionUID = 1L;
public static final String PARAM_NAME_RESET_ENABLE = "resetEnable";
public static final String PARAM_NAME_JMX_URL = "jmxUrl";
public static final String PARAM_NAME_JMX_USERNAME = "jmxUsername";
public static final String PARAM_NAME_JMX_PASSWORD = "jmxPassword";
private DruidStatService statService = DruidStatService.getInstance();
/** web.xml中配置的jmx的连接地址 */
private String jmxUrl = null;
/** web.xml中配置的jmx的用户名 */
private String jmxUsername = null;
/** web.xml中配置的jmx的密码 */
private String jmxPassword = null;
private MBeanServerConnection conn = null;
public StatViewServlet(){
super("support/http/resources");
}
public void init() throws ServletException {
super.init();
try {
String param = getInitParameter(PARAM_NAME_RESET_ENABLE);
if (param != null && param.trim().length() != 0) {
param = param.trim();
boolean resetEnable = Boolean.parseBoolean(param);
statService.setResetEnable(resetEnable);
}
} catch (Exception e) {
String msg = "initParameter config error, resetEnable : " + getInitParameter(PARAM_NAME_RESET_ENABLE);
LOG.error(msg, e);
}
// 获取jmx的连接配置信息
String param = readInitParam(PARAM_NAME_JMX_URL);
if (param != null) {
jmxUrl = param;
jmxUsername = readInitParam(PARAM_NAME_JMX_USERNAME);
jmxPassword = readInitParam(PARAM_NAME_JMX_PASSWORD);
try {
initJmxConn();
} catch (IOException e) {
LOG.error("init jmx connection error", e);
}
}
}
/**
* 读取servlet中的配置参数.
*
* @param key 配置参数名
* @return 配置参数值，如果不存在当前配置参数，或者为配置参数长度为0，将返回null
*/
private String readInitParam(String key) {
String value = null;
try {
String param = getInitParameter(key);
if (param != null) {
param = param.trim();
if (param.length() > 0) {
value = param;
}
}
} catch (Exception e) {
String msg = "initParameter config [" + key + "] error";
LOG.warn(msg, e);
}
return value;
}
/**
* 初始化jmx连接
*
* @throws IOException
*/
private void initJmxConn() throws IOException {
if (jmxUrl != null) {
JMXServiceURL url = new JMXServiceURL(jmxUrl);
Map env = null;
if (jmxUsername != null) {
env = new HashMap();
String[] credentials = new String[] { jmxUsername, jmxPassword };
env.put(JMXConnector.CREDENTIALS, credentials);
}
JMXConnector jmxc = JMXConnectorFactory.connect(url, env);
conn = jmxc.getMBeanServerConnection();
}
}
/**
* 根据指定的url来获取jmx服务返回的内容.
*
* @param connetion jmx连接
* @param url url内容
* @return the jmx返回的内容
* @throws Exception the exception
*/
private String getJmxResult(MBeanServerConnection connetion, String url) throws Exception {
ObjectName name = new ObjectName(DruidStatService.MBEAN_NAME);
String result = (String) conn.invoke(name, "service", new String[] { url },
new String[] { String.class.getName() });
return result;
}
/**
* 程序首先判断是否存在jmx连接地址，如果不存在，则直接调用本地的duird服务； 如果存在，则调用远程jmx服务。在进行jmx通信，首先判断一下jmx连接是否已经建立成功，如果已经
* 建立成功，则直接进行通信，如果之前没有成功建立，则会尝试重新建立一遍。.
*
* @param url 要连接的服务地址
* @return 调用服务后返回的json字符串
*/
protected String process(String url) {
String resp = null;
if (jmxUrl == null) {
resp = statService.service(url);
} else {
if (conn == null) {// 连接在初始化时创建失败
try {// 尝试重新连接
initJmxConn();
} catch (IOException e) {
LOG.error("init jmx connection error", e);
resp = DruidStatService.returnJSONResult(DruidStatService.RESULT_CODE_ERROR,
"init jmx connection error" + e.getMessage());
}
if (conn != null) {// 连接成功
try {
resp = getJmxResult(conn, url);
} catch (Exception e) {
LOG.error("get jmx data error", e);
resp = DruidStatService.returnJSONResult(DruidStatService.RESULT_CODE_ERROR, "get data error:"
+ e.getMessage());
}
}
} else {// 连接成功
try {
resp = getJmxResult(conn, url);
} catch (Exception e) {
LOG.error("get jmx data error", e);
resp = DruidStatService.returnJSONResult(DruidStatService.RESULT_CODE_ERROR,
"get data error" + e.getMessage());
}
}
}
return resp;
}
}