JavaEE學習日誌持續更新----> 必看!JavaEE學習路線(文章總彙)
JavaEE學習日誌(九十一)
Spring
AOP管理轉賬事務
xml配置實現
AccountDaoImpl
package com.itheima.dao.impl;
import com.itheima.dao.AccountDao;
import com.itheima.domain.Account;
import com.itheima.utils.ConnectionUtil;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import java.sql.SQLException;
@Repository
public class AccountDaoImpl implements AccountDao {
@Autowired
QueryRunner queryRunner;
@Autowired
ConnectionUtil connectionUtil;
@Override
public Account findByName(String name) {
String sql = "select * from account where name = ?";
try {
return queryRunner.query(connectionUtil.getThreadConnection(),sql,new BeanHandler<Account>(Account.class),name);
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
@Override
public void update(Account account) {
String sql = "update account set money = ? where name = ?";
try {
queryRunner.update(connectionUtil.getThreadConnection(),sql,account.getMoney(),account.getName());
} catch (SQLException e) {
e.printStackTrace();
}
}
}
AccountServiceImpl
package com.itheima.service.impl;
import com.itheima.dao.AccountDao;
import com.itheima.domain.Account;
import com.itheima.service.AccountService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class AccountServiceImpl implements AccountService {
@Autowired
AccountDao accountDao;
@Override
public void transfer(String fromName, String toName, Float money) {
//查詢轉賬的賬戶
Account fromAccount = accountDao.findByName(fromName);
//查詢接收的賬戶
Account toAccount = accountDao.findByName(toName);
//開始轉賬
fromAccount.setMoney(fromAccount.getMoney()-money);
toAccount.setMoney(toAccount.getMoney()+money);
//持久化到數據庫
accountDao.update(fromAccount);
accountDao.update(toAccount);
}
}
TransactionManager作爲通知對象
package com.itheima.utils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.sql.SQLException;
/**
* 事務管理器:是通知對象
* @author 黑馬程序員
* @Company http://www.ithiema.com *
* @Version 1.0
*/
@Component
public class TransactionManager {
@Autowired
private ConnectionUtil connectionUtil;
public void setConnectionUtil(ConnectionUtil connectionUtil) {
this.connectionUtil = connectionUtil;
}
//開啓事務
public void beginTransaction() {
//從當前線程上獲取連接,實現開啓事務
try {
connectionUtil.getThreadConnection().setAutoCommit(false);
} catch (SQLException e) {
e.printStackTrace();
}
}
//提交事務
public void commit() {
try {
connectionUtil.getThreadConnection().commit();
} catch (SQLException e) {
e.printStackTrace();
}
}
//回滾事務
public void rollback() {
try {
connectionUtil.getThreadConnection().rollback();
} catch (SQLException e) {
e.printStackTrace();
}
}
//釋放連接
public void release() {
try {
connectionUtil.getThreadConnection().setAutoCommit(true);
//關閉連接(還回池中)
connectionUtil.getThreadConnection().close();
//解綁線程:把連接和線程解綁
connectionUtil.remove();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
ConnectionUtil用於獲取連接
package com.itheima.utils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
/**
* 一個管理連接的工具類,用於實現連接和線程的綁定
* @author 黑馬程序員
* @Company http://www.ithiema.com
* @Version 1.0
*/
@Component
public class ConnectionUtil {
private ThreadLocal<Connection> tl = new ThreadLocal<Connection>();
@Autowired
private DataSource dataSource;
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
/**
* 獲取當前線程上綁定的連接
* @return
*/
public Connection getThreadConnection() {
try {
//1.先看看線程上是否綁了
Connection conn = tl.get();
if(conn == null) {
//2.從數據源中獲取一個連接
conn = dataSource.getConnection();
//3.和線程局部變量綁定
tl.set(conn);
}
//4.返回線程上的連接
return tl.get();
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
/**
* 把連接和當前線程解綁
*/
public void remove() {
tl.remove();
}
}
xml配置
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
<!--開啓註解-->
<context:component-scan base-package="com.itheima"></context:component-scan>
<!--dao層需要注入qr-->
<bean id = "queryRunner" class="org.apache.commons.dbutils.QueryRunner"></bean>
<!--創建dataSource-->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="${jdbc.driver}"></property>
<property name="jdbcUrl" value="${jdbc.url}"></property>
<property name="user" value="${jdbc.username}"></property>
<property name="password" value="${jdbc.password}"></property>
</bean>
<!--引入外部屬性文件-->
<context:property-placeholder location="jdbc.properties"></context:property-placeholder>
<!--使用aop解決事務問題
事務管理器類:通知對象
-->
<aop:config>
<!--切面-->
<aop:aspect ref="transactionManager">
<!--配置切入點-->
<aop:pointcut id="pointcut" expression="execution(* com.itheima.service..*.*(..))"/>
<!--配置通知-->
<!--前置增強,開啓事務-->
<aop:before method="beginTransaction" pointcut-ref="pointcut"></aop:before>
<!--後置增強,提交事務-->
<aop:after-returning method="commit" pointcut-ref="pointcut"></aop:after-returning>
<!--異常增強,回滾事務-->
<aop:after-throwing method="rollback" pointcut-ref="pointcut"></aop:after-throwing>
<!--最終增強,釋放資源-->
<aop:after method="release" pointcut-ref="pointcut"></aop:after>
</aop:aspect>
</aop:config>
</beans>
測試
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:applicationContext.xml")
public class TestSpring {
@Autowired
AccountService accountService;
@Test
public void test(){
accountService.transfer("aaa","ccc",20F);
}
}
註解配置實現
xml中
<!--開啓自動代理註解-->
<aop:aspectj-autoproxy></aop:aspectj-autoproxy>
在通知對象中配置註解
package com.itheima.utils;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.sql.SQLException;
/**
* 事務管理器:是通知對象
* @author 黑馬程序員
* @Company http://www.ithiema.com *
* @Version 1.0
*/
@Component
@Aspect
public class TransactionManager {
@Autowired
private ConnectionUtil connectionUtil;
public void setConnectionUtil(ConnectionUtil connectionUtil) {
this.connectionUtil = connectionUtil;
}
@Pointcut("execution(* com.itheima.service..*.*(..))")
public void pointcut(){}
/**
* 環繞增強
*/
@Around("pointcut()")
public void around(ProceedingJoinPoint joinPoint){
//執行原方法
try {
//前置增強
beginTransaction();
joinPoint.proceed();
//後置增強
commit();
} catch (Throwable throwable) {
//異常增強
rollback();
throwable.printStackTrace();
} finally {
//最終增強
release();
}
}
//開啓事務
public void beginTransaction() {
//從當前線程上獲取連接,實現開啓事務
try {
connectionUtil.getThreadConnection().setAutoCommit(false);
} catch (SQLException e) {
e.printStackTrace();
}
}
//提交事務
public void commit() {
try {
connectionUtil.getThreadConnection().commit();
} catch (SQLException e) {
e.printStackTrace();
}
}
//回滾事務
public void rollback() {
try {
connectionUtil.getThreadConnection().rollback();
} catch (SQLException e) {
e.printStackTrace();
}
}
//釋放連接
public void release() {
try {
connectionUtil.getThreadConnection().setAutoCommit(true);
//關閉連接(還回池中)
connectionUtil.getThreadConnection().close();
//解綁線程:把連接和線程解綁
connectionUtil.remove();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
也可以不配置切入點,直接在通知的註解中寫上表達式
@Around("execution(* com.itheima.service..*.*(..))")
jdbcTemplate
三種數據源的配置
三種數據源:c3p0,dbcp,spring自帶的數據源
引入依賴:其中spring自帶的數據源裏包含了jdbcTemplate
<dependency>
<groupId>c3p0</groupId>
<artifactId>c3p0</artifactId>
<version>0.9.1.2</version>
</dependency>
<!--dbcp數據源-->
<dependency>
<groupId>commons-dbcp</groupId>
<artifactId>commons-dbcp</artifactId>
<version>1.4</version>
</dependency>
<!--spring自帶數據源-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.0.2.RELEASE</version>
</dependency>
配置三種數據源
<!--引入外部屬性文件-->
<context:property-placeholder location="classpath:jdbc.properties"></context:property-placeholder>
<!--配置c3p0數據源-->
<bean id="c3p0DataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="${jdbc.driver}"></property>
<property name="jdbcUrl" value="${jdbc.url}"></property>
<property name="user" value="${jdbc.username}"></property>
<property name="password" value="${jdbc.password}"></property>
</bean>
<!--配置dbcp-->
<bean id="dbcpDataSource" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="${jdbc.driver}"></property>
<property name="url" value="${jdbc.url}"></property>
<property name="username" value="${jdbc.username}"></property>
<property name="password" value="${jdbc.password}"></property>
</bean>
<!--spring自帶的數據源-->
<bean id="springDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="${jdbc.driver}"></property>
<property name="url" value="${jdbc.url}"></property>
<property name="username" value="${jdbc.username}"></property>
<property name="password" value="${jdbc.password}"></property>
</bean>
jdbcTemplate的查詢操作
一、查詢全部
queryForList(sql語句)
返回值是list集合,list集合中是map集合query(sql語句,列與屬性的映射)
返回的是list集合,集合中是查詢的對象
創建列與屬性的映射類:結果集對象,每次都包含一行數據
package com.itheima.mapper;
import com.itheima.domain.Account;
import org.springframework.jdbc.core.RowMapper;
import java.sql.ResultSet;
import java.sql.SQLException;
public class AccountRowMapper implements RowMapper<Account> {
/**
*
* @param resultSet 結果集對象,只包含了一行數據
* @param i
* @return
* @throws SQLException
*/
@Override
public Account mapRow(ResultSet resultSet, int i) throws SQLException {
Account account = new Account();
int id = resultSet.getInt("id");
account.setId(id);
account.setName(resultSet.getString("name"));
account.setMoney(resultSet.getFloat("money"));
return account;
}
}
@Test
public void findAll(){
String sql = "select * from account";
//queryForList方法返回值是list集合,list集合中是map集合
// List<Map<String, Object>> accountList = jdbcTemplate.queryForList(sql);
// for (Map<String, Object> map : accountList) {
// System.out.println(map);
// }
//query
List<Account> list = jdbcTemplate.query(sql, new AccountRowMapper());
for (Account account : list) {
System.out.println(account);
}
}
二、根據id查詢
query(sql語句,列與屬性的映射,參數)
和上述基本一致,返回一個list集合queryForObject(sql語句,列與屬性的映射,參數)
查詢一個對象queryForObject(sql語句,參數列表(必須是數組類型),jdbcTemplate自帶映射:必須保證屬性和列名一致)
這個方法只能當列與屬性名相同時使用,也是返回一個對象,不建議使用
@Test
public void findById(){
String sql = "select * from account where id = ?";
// List<Account> list = jdbcTemplate.query(sql, new AccountRowMapper(),1);
//queryForObject(sql語句,列與屬性的映射,參數)查詢一個對象
// Account account = jdbcTemplate.queryForObject(sql, new AccountRowMapper(), 1);
// System.out.println(account);
//queryForObject(sql語句,參數列表(必須是數組類型),jdbcTemplate自帶映射:必須保證屬性和列名一致)
Account account = jdbcTemplate.queryForObject(sql, new Object[]{1}, new BeanPropertyRowMapper<>(Account.class));
System.out.println(account);
}
三、聚合函數
queryForObject(sql, 返回值類型)
@Test
public void totalCount() {
String sql = "select count(*) from account";
//queryForObject(sql語句,返回值類型)
Integer integer = jdbcTemplate.queryForObject(sql, Integer.class);
System.out.println(integer);
}
jdbcTemplate的增刪改操作
和dbUtils一樣,update方法
@Test
public void save(){
String sql = "insert into account values(null,?,?)";
jdbcTemplate.update(sql,"ddd",500);
}
@Test
public void update(){
String sql = "update account set money = ? , name = ? where id = ?";
jdbcTemplate.update(sql,1000F,"eee",5);
}
@Test
public void del() {
String sql = "delete from account where id = ?";
jdbcTemplate.update(sql,5);
}
jdbcTemplate在dao層中兩種使用方法
第一種:和上述一樣,使用spring相關技術即可
第二種:
- 在dao層的實現類種繼承接口
JdbcDaoSupport
public class AccountDaoImpl2 extends JdbcDaoSupport implements AccountDao
- 所有的dao對象需要在xml中創建,並通過set方法注入數據源對象
<!--創建dao層對象-->
<bean id="accountDao" class="com.itheima.dao.impl.AccountDaoImpl2">
<!--通過set方法注入數據源-->
<property name="dataSource" ref="springDataSource"></property>
</bean>
- 使用
getJdbcTemplate()
獲取jdbcTemplate
@Override
public List<Account> findAll() {
String sql = "select * from account";
List<Account> accountList = getJdbcTemplate().query(sql, new AccountRowMapper());
return accountList;
}