VML勾画流程图(六)db4o后续问题

VML勾画流程图(六)db4o后续问题

问题一：
每次在关闭tomcat的时候，控制台都会有错误信息打印出来。
报错如下：
严重: A web application created a ThreadLocal with key of type [org.springframework.core.NamedThreadLocal] (value [Prototype beans currently in creation]) and a value of type [null] (value [null]) but failed to remove it when the web application was stopped. To prevent a memory leak, the ThreadLocal has been forcibly removed.
2010-4-22 22:09:52 org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
严重: A web application created a ThreadLocal with key of type [org.springframework.core.NamedThreadLocal] (value [Prototype beans currently in creation]) and a value of type [null] (value [null]) but failed to remove it when the web application was stopped. To prevent a memory leak, the ThreadLocal has been forcibly removed.
2010-4-22 22:09:52 org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
严重: A web application created a ThreadLocal with key of type [org.springframework.core.NamedThreadLocal] (value [Prototype beans currently in creation]) and a value of type [null] (value [null]) but failed to remove it when the web application was stopped. To prevent a memory leak, the ThreadLocal has been forcibly removed.
2010-4-22 22:09:52 org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
严重: A web application created a ThreadLocal with key of type [org.codehaus.groovy.runtime.GroovyCategorySupport.MyThreadLocal] (value [org.codehaus.groovy.runtime.GroovyCategorySupport$MyThreadLocal@1648e6f]) and a value of type [java.lang.ref.SoftReference] (value [java.lang.ref.SoftReference@c32254]) but failed to remove it when the web application was stopped. To prevent a memory leak, the ThreadLocal has been forcibly removed.
log4j:ERROR LogMananger.repositorySelector was null likely due to error in class reloading, using NOPLoggerRepository.

有人说是TOMCAT的BUG
tomcat6.0.24和ORACLE10g JDBC，MYSQL5 JDBC的兼容性都有问题！
http://hi.baidu.com/rtsbtx/blog/item/841c4f1f44ca02c3a786693b.html

我换成6.0.20之后就好了，不过这里到底有没有memory leak，以后还要多观察。

问题二：
以前我把db4o的db4oDAOImpl想得太简单了，而且local和remote那么弄不得行：），只能不考虑client或者本地yap文件的频繁打开和关闭问题，将对db4o的操作做调整。
web.xml中增加启动项，启动tomcat的时候就开启db4o的server，当然是根据配置来走。
<listener>
<listener-class>com.sillycat.easyworkflow.commons.listeners.Db4oContextLoaderListener</listener-class>
</listener>

Db4oContextLoaderListener.java的内容如下，做了哪些事情呢:
package com.sillycat.easyworkflow.commons.listeners;
import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.web.context.ContextLoaderListener;
import org.springframework.web.context.support.WebApplicationContextUtils;
import com.db4o.ObjectServer;
import com.db4o.cs.Db4oClientServer;
import com.sillycat.easyworkflow.commons.config.WebAppConfiguration;

public class Db4oContextLoaderListener extends ContextLoaderListener implements
ServletContextListener {
private final Log log = LogFactory.getLog(getClass());
private ObjectServer server;
public void contextInitialized(ServletContextEvent event) {
super.contextInitialized(event);
ServletContext context = event.getServletContext();
ApplicationContext ctx = WebApplicationContextUtils
.getRequiredWebApplicationContext(context);
WebAppConfiguration webAppConfiguration = (WebAppConfiguration) ctx
.getBean("webAppConfiguration");
if (!webAppConfiguration.isEnableLocal()) {
log.info("=============================  begin to init dbo4   =====================");
initdb4o(webAppConfiguration);
log.info("=============================  end   to init dbo4   =====================");
}
}
public void contextDestroyed(ServletContextEvent event) {
if(this.server != null){
log.info("shutdown the db4o server");
this.server.close();
}
}
public void initdb4o(WebAppConfiguration webAppConfiguration) {
log.info("serverfilename:" + webAppConfiguration.getServerFileName());
log.info("port:" + webAppConfiguration.getPort());
log.info("username:" + webAppConfiguration.getUsername());
this.server = Db4oClientServer.openServer(Db4oClientServer
.newServerConfiguration(), webAppConfiguration
.getServerFileName(), webAppConfiguration.getPort());
this.server.grantAccess(webAppConfiguration.getUsername(),
webAppConfiguration.getPassword());
}
}

配置类WebAppConfiguration.java如下：
public class WebAppConfiguration {
private String workflowPath;
// 是否是本地服务
private boolean enableLocal = true;
// 本地数据库文件名字
private String localFileName = "local.yap";
// 服务端数据库文件名字
private String serverFileName = "server.yap";
// 服务器端口
private int port = 1212;
// 用户名
private String username = "sillycat";
// 密码
private String password = "111111";
// 服务器地址
private String serverhost = "localhost";
...snip...
}

properties的数据如下：
db4o.enableLocal=true
db4o.local.filename=e:/work/easyworkflow/db/local.yap
db4o.server.filename=e:/work/easyworkflow/db/server.yap
db4o.server.port=1212
db4o.server.username=sillycat
db4o.server.password=111111
db4o.server.serverhost=localhost

原来的workflowManagerImpl要做如下修改：
package com.sillycat.easyworkflow.service.impl;

import java.util.ArrayList;
import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.db4o.Db4oEmbedded;
import com.db4o.ObjectContainer;
import com.db4o.ObjectSet;
import com.db4o.cs.Db4oClientServer;
import com.db4o.query.Predicate;
import com.sillycat.easyworkflow.commons.config.WebAppConfiguration;
import com.sillycat.easyworkflow.commons.utils.Db4oUtil;
import com.sillycat.easyworkflow.commons.utils.StringUtil;
import com.sillycat.easyworkflow.model.Workflow;
import com.sillycat.easyworkflow.model.WorkflowDefinition;
import com.sillycat.easyworkflow.model.WorkflowDefinitionQuery;
import com.sillycat.easyworkflow.service.WorkflowManager;

@Service("workflowManager")
public class WorkflowManagerImpl implements WorkflowManager {

public Logger logger = LoggerFactory.getLogger(this.getClass());

private WebAppConfiguration webAppConfiguration;

public ObjectContainer opendb() {
ObjectContainer db = null;
if (webAppConfiguration.isEnableLocal()) {
db = Db4oEmbedded.openFile(Db4oEmbedded.newConfiguration(),
webAppConfiguration.getLocalFileName());
logger.info("init local db4o file = "
+ webAppConfiguration.getLocalFileName());
} else {
db = Db4oClientServer.openClient(Db4oClientServer
.newClientConfiguration(), webAppConfiguration
.getServerhost(), webAppConfiguration.getPort(),
webAppConfiguration.getUsername(), webAppConfiguration
.getPassword());
logger.info("init remote db4o server "
+ webAppConfiguration.getServerhost() + ":"
+ webAppConfiguration.getPort());
}
return db;
}

@Autowired
public void setWebAppConfiguration(WebAppConfiguration webAppConfiguration) {
this.webAppConfiguration = webAppConfiguration;
}

/**
* use for show page,get flow instances information by flow id
*/
public Workflow getWorkflowById(String workflowInstanceId) {
if (StringUtil.isBlank(workflowInstanceId)) {
logger.info("workflowInstanceId can't be blank when get workflow!");
return null;
}
Workflow workflow = new Workflow(workflowInstanceId);
ObjectContainer db = null;
try {
db = opendb();
ObjectSet<Workflow> os = db.queryByExample(workflow);
Db4oUtil<Workflow> db4oUtil = new Db4oUtil<Workflow>();
workflow = db4oUtil.retrieveObject(os);
} catch (Exception e) {
logger.error("error:" + e);
} finally {
db.close();
}
return workflow;
}

/**
* save flow instances information
*/
public void saveWorkflow(Workflow workflow) {
if (workflow == null
|| StringUtil.isBlank(workflow.getWorkflowInstanceId())) {
logger
.info("object and workflowInstanceId can't be null,when save!");
return;
}
ObjectContainer db = null;
try {
db = opendb();
Workflow search = new Workflow(workflow.getWorkflowInstanceId());
ObjectSet<Workflow> os = db.queryByExample(search);
Db4oUtil<Workflow> db4oUtil = new Db4oUtil<Workflow>();
Workflow t = db4oUtil.retrieveObject(os);
if (t == null) {
// insert new object in the database
db.store(workflow);
logger
.debug("object workflow="
+ workflow.getWorkflowInstanceId()
+ " newly inserted!");
} else {
// update object in the database
t.setSteps(workflow.getSteps());
t.setWorkflowName(workflow.getWorkflowName());
db.store(t);
logger.debug("object workflow="
+ workflow.getWorkflowInstanceId() + " updated!");
}
db.commit();
} catch (Exception e) {
logger.error("error:" + e);
} finally {
db.close();
}
}

/**
* save flow definition information
*
* @param workflowDefinition
*/
public void saveWorkflowDefinition(WorkflowDefinition workflowDefinition) {
if (workflowDefinition == null
|| StringUtil.isBlank(workflowDefinition.getWorkflowName())) {
logger.info("object and workflowName can't be null,when save!");
return;
}
ObjectContainer db = null;
try {
db = opendb();
WorkflowDefinition search = new WorkflowDefinition(
workflowDefinition.getWorkflowName());
ObjectSet<WorkflowDefinition> os = db.queryByExample(search);
Db4oUtil<WorkflowDefinition> db4oUtil = new Db4oUtil<WorkflowDefinition>();
WorkflowDefinition t = db4oUtil.retrieveObject(os);
if (t == null) {
// insert new object in the database
db.store(workflowDefinition);
logger.debug("object workflowDefinition="
+ workflowDefinition.getWorkflowName()
+ " newly inserted!");
} else {
// update object in the database
t.setAliasName(workflowDefinition.getAliasName());
t.setContent(workflowDefinition.getContent());
db.store(t);
logger.debug("object workflowDefinition="
+ workflowDefinition.getWorkflowName() + " updated!");
}
db.commit();
} catch (Exception e) {
logger.error("error:" + e);
} finally {
db.close();
}
}

/**
* get the flow definition information by workflowName
*
* @param workflowName
* @return
*/
public WorkflowDefinition getWorkflowDefinitionByWorkflowName(
String workflowName) {
if (StringUtil.isBlank(workflowName)) {
logger
.info("workflowName can't be blank when get workflowDefinition!");
return null;
}
WorkflowDefinition wfDefinition = new WorkflowDefinition(workflowName);
ObjectContainer db = null;
try {
db = opendb();
ObjectSet<WorkflowDefinition> os = db.queryByExample(wfDefinition);
Db4oUtil<WorkflowDefinition> db4oUtil = new Db4oUtil<WorkflowDefinition>();
wfDefinition = db4oUtil.retrieveObject(os);
} catch (Exception e) {
logger.error("error:" + e);
} finally {
db.close();
}
return wfDefinition;
}

/**
* list all the flow definition information
*
* @return
*/
public List<WorkflowDefinition> allWorkflowDefinition() {
List<WorkflowDefinition> list = null;
WorkflowDefinition wfDefinition = new WorkflowDefinition();
ObjectContainer db = null;
try {
db = opendb();
ObjectSet<WorkflowDefinition> os = db.queryByExample(wfDefinition);
Db4oUtil<WorkflowDefinition> db4oUtil = new Db4oUtil<WorkflowDefinition>();
list = db4oUtil.retrieveList(os);
} catch (Exception e) {
logger.error("error:" + e);
} finally {
db.close();
}
return list;
}

/**
* query the flow definition information with page parameters
*
* @param query
* @return
*/
public List<WorkflowDefinition> queryWorkflowDefinition(
WorkflowDefinitionQuery query) {
List<WorkflowDefinition> os = null;
List<WorkflowDefinition> list = null;
final String workflowName = query.getWorkflowName();
final String aliasName = query.getAliasName();
ObjectContainer db = null;
try {
db = opendb();
os = db.query(new Predicate<WorkflowDefinition>() {
private static final long serialVersionUID = 8058916779101664916L;

public boolean match(WorkflowDefinition wd) {
boolean flag = true;
if (StringUtil.isNotBlank(workflowName)) {
flag = wd.getWorkflowName().equalsIgnoreCase(
workflowName);
}
if (StringUtil.isNotBlank(aliasName)) {
flag = flag
&& wd.getAliasName()
.equalsIgnoreCase(aliasName);
}
return flag;
}
});
if (os != null && !os.isEmpty()) {
query.setTotal(os.size());
}
list = new ArrayList<WorkflowDefinition>(query.getEnd()
- query.getStart() + 1);
for (int i = (query.getStart() - 1); i < query.getEnd(); i++) {
list.add(os.get(i));
}
} catch (Exception e) {
logger.error("error:" + e);
} finally {
db.close();
}
return list;
}

/**
*
* @param workflowName
*/
public void deleteWorkflowDefinitionByWorkflowName(String workflowName) {
if (StringUtil.isBlank(workflowName)) {
logger
.info("workflowName can't be blank when delete workflowdefinition!");
return;
}
ObjectContainer db = null;
try {
db = opendb();
WorkflowDefinition search = new WorkflowDefinition(workflowName);
ObjectSet<WorkflowDefinition> os = db.queryByExample(search);
Db4oUtil<WorkflowDefinition> db4oUtil = new Db4oUtil<WorkflowDefinition>();
WorkflowDefinition workflowDefinition = db4oUtil.retrieveObject(os);
if (workflowDefinition == null) {
logger.info("I can't find workflowDefinition=" + workflowName
+ " in database");
return;
}
db.delete(workflowDefinition);
db.commit();
} catch (Exception e) {
logger.error("error:" + e);
} finally {
db.close();
}
}
}