ThreadLocal处理事务（demo）

1.pom.xml

<!-- Spring-data-jpa依赖 自动创建表-->
<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

<!--lombok 省去写set、get的麻烦-->
<dependency>
	<groupId>org.projectlombok</groupId>
	<artifactId>lombok</artifactId>
	<version>1.16.14</version>
</dependency>

<!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
<dependency>
	<groupId>com.alibaba</groupId>
	<artifactId>druid</artifactId>
	<version>1.0.29</version>
</dependency>

2.application.yml

#datasource
spring:
    datasource:
        name: era
        url: jdbc:mysql://localhost:3306/test1?useUnicode=true&characterEncoding=UTF-8&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
        username: root
        password: 123456
        # 使用druid数据源
        type: com.alibaba.druid.pool.DruidDataSource
        driver-class-name: com.mysql.jdbc.Driver
        # 下面为连接池的补充设置，应用到上面所有数据源中
        # 初始化大小，最小，最大
        initialSize: 5
        minIdle: 5
        maxActive: 20
        # 配置获取连接等待超时的时间
        maxWait: 60000
        # 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒
        timeBetweenEvictionRunsMillis: 60000
        # 配置一个连接在池中最小生存的时间，单位是毫秒
        minEvictableIdleTimeMillis: 300000
        validationQuery: SELECT 1 FROM DUAL
        testWhileIdle: true
        testOnBorrow: false
        testOnReturn: false
        # 打开PSCache，并且指定每个连接上PSCache的大小
        poolPreparedStatements: true
        maxPoolPreparedStatementPerConnectionSize: 20
        # 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
        spring.datasource.filters: stat,wall,log4j
        # 通过connectProperties属性来打开mergeSql功能；慢SQL记录
        connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
        # 合并多个DruidDataSource的监控数据
        #useGlobalDataSourceStat: true
    jpa:
      hibernate:
        ddl-auto: update
      show-sql: true

3.DruidDataSourceConfig.java

package com.example.threadlocal;

import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;
import com.alibaba.druid.support.spring.stat.DruidStatInterceptor;
import org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import javax.sql.DataSource;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;

@Configuration
@EnableTransactionManagement
/**
 * Druid的DataResource配置类
 * Created by fee
 */
public class DruidDataSourceConfig {

    @Value("${spring.datasource.name}")
    String applicationName;
    @Value("${spring.datasource.url}")
    String url;
    @Value("${spring.datasource.driver-class-name}")
    String driverClassName;
    @Value("${spring.datasource.username}")
    String username;
    @Value("${spring.datasource.password}")
    String password;
    @Value("${spring.datasource.initialSize}")
    Integer initialSize;
    @Value("${spring.datasource.minIdle}")
    Integer minIdle;
    @Value("${spring.datasource.maxWait}")
    Long maxWait;
    @Value("${spring.datasource.maxActive}")
    Integer maxActive;
    @Value("${spring.datasource.minEvictableIdleTimeMillis}")
    Long minEvictableIdleTimeMillis;

    @Bean
    public DataSource dataSource() {
        DruidDataSource datasource = new DruidDataSource();
        datasource.setUrl(url);
        datasource.setDriverClassName(driverClassName);
        datasource.setUsername(username);
        datasource.setPassword(password);
        datasource.setInitialSize(Integer.valueOf(initialSize));
        datasource.setMinIdle(Integer.valueOf(minIdle));
        datasource.setMaxWait(Long.valueOf(maxWait));
        datasource.setMaxActive(Integer.valueOf(maxActive));
        datasource.setMinEvictableIdleTimeMillis(
                Long.valueOf(minEvictableIdleTimeMillis));
        try {
            datasource.setFilters("stat,wall");
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return datasource;
    }

    @Bean
    public ServletRegistrationBean druidServlet() {
        ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean();
        servletRegistrationBean.setServlet(new StatViewServlet());
        servletRegistrationBean.addUrlMappings("/druid/*");
        Map<String, String> initParameters = new HashMap<String, String>();
        // initParameters.put("loginUsername", "druid");// 用户名
        // initParameters.put("loginPassword", "druid");// 密码
        initParameters.put("resetEnable", "false");// 禁用HTML页面上的“Reset All”功能
        initParameters.put("allow", "127.0.0.1"); // IP白名单 (没有配置或者为空，则允许所有访问)
        // initParameters.put("deny", "192.168.20.38");// IP黑名单
        // (存在共同时，deny优先于allow)
        servletRegistrationBean.setInitParameters(initParameters);
        return servletRegistrationBean;
    }

    @Bean
    public FilterRegistrationBean filterRegistrationBean() {
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        filterRegistrationBean.setFilter(new WebStatFilter());
        filterRegistrationBean.addUrlPatterns("/*");
        filterRegistrationBean.addInitParameter("exclusions", "*.js,*.gif,*.jpg,*.bmp,*.png,*.css,*.ico,/druid/*");
        return filterRegistrationBean;
    }

    // 按照BeanId来拦截配置 用来bean的监控
    @Bean(value = "druid-stat-interceptor")
    public DruidStatInterceptor DruidStatInterceptor() {
        DruidStatInterceptor druidStatInterceptor = new DruidStatInterceptor();
        return druidStatInterceptor;
    }

    @Bean
    public BeanNameAutoProxyCreator beanNameAutoProxyCreator() {
        BeanNameAutoProxyCreator beanNameAutoProxyCreator = new BeanNameAutoProxyCreator();
        beanNameAutoProxyCreator.setProxyTargetClass(true);
        // 设置要监控的bean的id
        //beanNameAutoProxyCreator.setBeanNames("sysRoleMapper","loginController");
        beanNameAutoProxyCreator.setInterceptorNames("druid-stat-interceptor");
        return beanNameAutoProxyCreator;
    }

}

4.SpringUtil.java(获取bean）

package com.example.threadlocal;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

@Component
public class SpringUtil implements ApplicationContextAware {

    private static ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        if(SpringUtil.applicationContext == null) {
            SpringUtil.applicationContext = applicationContext;
        }
    }

    //获取applicationContext
    public static ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    //通过name获取 Bean.
    public static Object getBean(String name){
        return getApplicationContext().getBean(name);
    }

    //通过class获取Bean.
    public static <T> T getBean(Class<T> clazz){
        return getApplicationContext().getBean(clazz);
    }

    //通过name,以及Clazz返回指定的Bean
    public static <T> T getBean(String name,Class<T> clazz){
        return getApplicationContext().getBean(name, clazz);
    }

}

5.ConnectionManager.java

package com.example.threadlocal;

import com.alibaba.druid.pool.DruidDataSource;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;

/**
 * 连接池工具
 */
public class ConnectionManager {
    static DataSource dataSource;
    private static ThreadLocal<Connection> connThreadlocal = new ThreadLocal<Connection>();
    private static Connection conn = null;

    static {
        dataSource = SpringUtil.getBean(DruidDataSource.class);
    }

    /**
     * 获取连接
     * @return
     * @throws Exception
     */
    public static Connection getConnection() {
        if (connThreadlocal.get() == null) {
            try {
                conn = dataSource.getConnection();
                conn.setAutoCommit(false);
                connThreadlocal.set(conn);
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        return connThreadlocal.get();
    }

    /**
     * 关闭连接
     * @return
     * @throws Exception
     */
    public static void close() {
        try {
            connThreadlocal.get().setAutoCommit(true);
            dataSource.getConnection().close();
            connThreadlocal.get().close();
            connThreadlocal.set(null);
        } catch (SQLException e) {
            e.printStackTrace();
        }

    }

    /**
     * 提交
     * @return
     * @throws Exception
     */
    public static void commit() {
        try {
            connThreadlocal.get().commit();
            connThreadlocal.get().setAutoCommit(true);
        } catch (SQLException e) {
            rollback();
        } finally {
            close();
        }
    }

    /**
     * 回滚
     * @return
     * @throws Exception
     */
    public static void rollback() {
        try {
            connThreadlocal.get().rollback();
            connThreadlocal.get().setAutoCommit(true);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

6.User.java

package com.example.threadlocal;

import lombok.Data;

import javax.persistence.*;

@Data
@Entity
@Table(name = "USER")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    @Column(length = 20)
    private String name;
}

7.UserDao.java

package com.example.threadlocal;

import org.springframework.stereotype.Repository;

import java.sql.Connection;
import java.sql.PreparedStatement;

@Repository
public class UserDao {

    /**
     * 添加
     * @return
     */
    public int add() {
        Connection conn = null;
        PreparedStatement ps = null;
        int result = 0;
        try {
            conn = ConnectionManager.getConnection();
            ps = conn.prepareStatement("insert into user(name) values (?)");
            ps.setString(1, "小白");
            result = ps.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (ps != null) {
                    ps.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return result;
    }

    /**
     * 删除
     * @return
     */
    public int delete() {
        Connection conn = null;
        PreparedStatement ps = null;
        int result = 0;
        try {
            conn = ConnectionManager.getConnection();
            ps = conn.prepareStatement("delete from user where name=?");
            ps.setString(1, "小白");
            result = ps.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (ps != null) {
                    ps.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return result;
    }

}

8.UserService.java

package com.example.threadlocal;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UserService {
    @Autowired
    UserDao userDao;
    public void test() {
        userDao.add();
        userDao.delete();
        ConnectionManager.commit();
    }
}

9.UserController.java

package com.example.threadlocal;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class UserController {

    @Autowired
    UserService userService;
    @GetMapping("test")
    public String test() {
        userService.test();
        return "success";
    }
}

10.访问 http://localhost:8080/test，可以在service层中认为制造异常，观察数据库的插入情况。

ThreadLocal处理事务（demo）

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