工具类：mybatis中使用Threadlocal开启session及关闭session

1、线程容器,给线程绑定一个object 内容,后只要线程不变,可以随时取出.

1.1 改变线程,无法取出内容.

1 final threadlocal threadlocal = new threadlocal<>();
2 threadlocal.set("测试");
3 new thread(){
4     public void run() {
5         string result = threadlocal.get();
6         system.out.println("结果:"+result);
7     };
8 }.start();

2、使用threadlocal简化开发

2.1定义工具类

    将sqlsession创建出来，存放到threadlocal中，需要时再从中取出

 1 package com.test.util;
 2 
 3 import java.io.ioexception;
 4 import java.io.inputstream;
 5 
 6 import org.apache.ibatis.io.resources;
 7 import org.apache.ibatis.session.sqlsession;
 8 import org.apache.ibatis.session.sqlsessionfactory;
 9 import org.apache.ibatis.session.sqlsessionfactorybuilder;
10 
11 public class mybatisutil {
12 
13     //工厂
14     private static sqlsessionfactory factory;
15     //线程容器
16     private static threadlocal<sqlsession> tl = new threadlocal<>();
17     
18     
19     static{
20         try {
21             inputstream is = resources.getresourceasstream("mybatis.xml");
22             factory = new sqlsessionfactorybuilder().build(is);
23         } catch (ioexception e) {
24             e.printstacktrace();
25         }
26     }
27     /**
28      * 获取session
29      * 从线程容器中获取，没有则创建session在存放到线程容器中
30      * @return
31      */
32     public static sqlsession getsession(){
33         sqlsession sqlsession = tl.get();
34         if(sqlsession == null){
35             sqlsession = factory.opensession();
36             tl.set(sqlsession);
37         }
38         return tl.get();
39     }
40     
41     /**
42      * 关闭session
43      * 从容器线程中获取session，有则关闭，且将线程容器的session清空
44      */
45     public static void closesession(){
46         sqlsession sqlsession = tl.get();
47         if(sqlsession != null){
48             sqlsession.close();
49         }
50         tl.set(null);
51     }
52 }

2.2 定义过滤器

    过滤器可以在调用方法前及方法后添加代码

 1 package com.test.filter;
 2 
 3 import java.io.ioexception;
 4 
 5 import java.io.inputstream;
 6 
 7 import javax.servlet.filter;
 8 import javax.servlet.filterchain;
 9 import javax.servlet.filterconfig;
10 import javax.servlet.servletexception;
11 import javax.servlet.servletrequest;
12 import javax.servlet.servletresponse;
13 import javax.servlet.annotation.webfilter;
14 
15 import org.apache.ibatis.io.resources;
16 import org.apache.ibatis.session.sqlsession;
17 import org.apache.ibatis.session.sqlsessionfactory;
18 import org.apache.ibatis.session.sqlsessionfactorybuilder;
19 
20 import com.test.util.mybatisutil;
21 
22 
23 /**
24  * 最开始是由spring框架提出的.整合hibernate框架是使用的是opensessioninview
25  * 
26  * 
27  * @author administrator
28  *
29  */
30 @webfilter("/*")
31 public class opensessioninview implements filter{
32 
33     @override
34     public void init(filterconfig filterconfig) throws servletexception {
35         // todo auto-generated method stub
36     }
37 
38     @override
39     public void dofilter(servletrequest servletrequest, servletresponse servletresponse, filterchain filterchain)
40             throws ioexception, servletexception {
41 //        inputstream is = resources.getresourceasstream("mybatis.xml");
42 //        sqlsessionfactory factory = new sqlsessionfactorybuilder().build(is);
43 //        sqlsession session = factory.opensession();        
44         sqlsession session = mybatisutil.getsession();
45         try {
46             filterchain.dofilter(servletrequest, servletresponse);
47             session.commit();
48         } catch (exception e) {
49             session.rollback();
50             e.printstacktrace();
51         }finally{
52             mybatisutil.closesession();
53         }
54 //        session.commit();
55 //        session.close();
56     }
57 
58     @override
59     public void destroy() {
60         // todo auto-generated method stub    
61     }
62 }