Java ThreadLocal

Java ThreadLocal

//ThreadLocal第一种用法：

//建表：

-- Create table

create table USERBEAN

(

  ID       NVARCHAR2(40) not null,

  USERNAME NVARCHAR2(40),

  PASSWORD NVARCHAR2(40)

)

tablespace USERS

  pctfree 10

  initrans 1

  maxtrans 255

  storage

  (

    initial 64K

    minextents 1

    maxextents unlimited

  );

-- Create/Recreate primary, unique and foreign key constraints 

alter table USERBEAN

  add constraint SSSID primary key (ID)

  using index 

  tablespace USERS

  pctfree 10

  initrans 2

  maxtrans 255

  storage

  (

    initial 64K

    minextents 1

    maxextents unlimited

  );

package com.abin.lee.collection.threadlocal;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.SQLException;

public class MyThreadLocal {

//使用ThreadLocal保存Connection变量

public static ThreadLocal<Connection> threadLocal = new ThreadLocal<Connection>();

private static final String URL = "jdbc:oracle:thin:@localhost:1521:XE";

private static final String USERNAME = "abing";

private static final String PWD = "abing";

public static Connection getConnection() {

Connection connection = null;

String url = "";

//如果connThreadLocal没有本线程对应的Connection创建一个新的Connection，并将其保存到线程本地变量中。

if (threadLocal.get() == null) {

try {

Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();

connection = DriverManager.getConnection(URL, USERNAME, PWD);

threadLocal.set(connection);

} catch (Exception e) {

e.printStackTrace();

}

}else {

return threadLocal.get();//直接返回线程本地变量

}

return connection;

}

public static void remove() {

threadLocal.remove();

}

}

package com.abin.lee.collection.threadlocal;

import java.io.Serializable;

public class UserBean implements Serializable{

private String id;

private String username;

private String password;

public String getId() {

return id;

}

public void setId(String id) {

this.id = id;

}

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

}

//测试代码

package com.abin.lee.collection.threadlocal;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.util.ArrayList;

import java.util.List;

public class OracleOperate {

public static List<UserBean> findAll(){

Connection conn=null;

PreparedStatement ps=null;

ResultSet rs=null;

String sql="select * from userbean order by id desc";

List<UserBean> list=new ArrayList<UserBean>();

UserBean user=null;

try {

conn=MyThreadLocal.getConnection();

ps=conn.prepareStatement(sql);

rs=ps.executeQuery();

while (rs.next()&&rs!=null) {

user=new UserBean();

user.setId(rs.getString("id"));

user.setUsername(rs.getString("username"));

user.setPassword(rs.getString("password"));

list.add(user);

}

} catch (Exception e) {

e.printStackTrace();

}

return list;

}

public static void main(String[] args) {

List<UserBean> list=findAll();

for(UserBean lst:list){

System.out.println("id="+lst.getId());

System.out.println("username="+lst.getUsername());

System.out.println("id="+lst.getPassword());

}

}

}










//ThreadLocal第二种用法： 

package com.abin.lee.collection.threadlocal;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.SQLException;

public class MyThreadLocal {

private static final String URL = "jdbc:oracle:thin:@localhost:1521:XE";

private static final String USERNAME = "abing";

private static final String PWD = "abing";

//使用ThreadLocal保存Connection变量

public static ThreadLocal<Connection> threadLocal = new ThreadLocal<Connection>(){

protected Connection initialValue() {

Connection connection = null;

//如果connThreadLocal没有本线程对应的Connection创建一个新的Connection，并将其保存到线程本地变量中。

if (connection == null) {

try {

Class.forName("oracle.jdbc.driver.OracleDriver").newInstance();

connection = DriverManager.getConnection(URL, USERNAME, PWD);

} catch (Exception e) {

e.printStackTrace();

}

}

return connection;

}

};

public static Connection getConnection() {

return threadLocal.get();

}

public static void remove() {

threadLocal.remove();

}

}

package com.abin.lee.collection.threadlocal;

import java.io.Serializable;

public class UserBean implements Serializable{

private String id;

private String username;

private String password;

public String getId() {

return id;

}

public void setId(String id) {

this.id = id;

}

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

}

package com.abin.lee.collection.threadlocal;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.util.ArrayList;

import java.util.List;

public class OracleOperate {

public static List<UserBean> findAll(){

Connection conn=null;

PreparedStatement ps=null;

ResultSet rs=null;

String sql="select * from userbean order by id desc";

List<UserBean> list=new ArrayList<UserBean>();

UserBean user=null;

try {

conn=MyThreadLocal.getConnection();

ps=conn.prepareStatement(sql);

rs=ps.executeQuery();

while (rs.next()&&rs!=null) {

user=new UserBean();

user.setId(rs.getString("id"));

user.setUsername(rs.getString("username"));

user.setPassword(rs.getString("password"));

list.add(user);

}

} catch (Exception e) {

e.printStackTrace();

}

return list;

}

public static void main(String[] args) {

List<UserBean> list=findAll();

for(UserBean lst:list){

System.out.println("id="+lst.getId());

System.out.println("username="+lst.getUsername());

System.out.println("id="+lst.getPassword());

}

}

}