模拟转账成功时的业务场景
1 import java.sql.*;
2
3 public class TransactionDemo1 {
4
11
12 public static void main(String[] args) throws SQLException, ClassNotFoundException {
13 String url = "jdbc:mysql://localhost/xh";
14 String username = "xiaohengdada";
15 String password = "123456";
16
17 Class.forName("org.gjt.mm.mysql.Driver");
18 Connection conn = null;
19 PreparedStatement st = null;
20 ResultSet rs = null;
21
22 try {
23 conn = DriverManager.getConnection(url, username, password);
24 conn.setAutoCommit(false);// 通知数据库开启事务(start transaction)
25 String sql1 = "update account set money=money+100 where name=‘A‘";
26 st = conn.prepareStatement(sql1);
27 int num1 = st.executeUpdate();
28 if (num1 > 0) {
29 System.out.println("succeed to update A ");
30 }
31 String sql2 = "update account set money=money-100 where name=‘B‘";
32 st = conn.prepareStatement(sql2);
33 int num2 = st.executeUpdate();
34 if (num2 > 0) {
35 System.out.println("succeed to update B ");
36 }
37 conn.commit();// 上面的两条SQL执行Update语句成功之后就通知数据库提交事务(commit)
38 System.out.println("成功！！！"); // log4j
39 } catch (Exception e) {
40 e.printStackTrace();
41 } finally {
42 // rs.close();
43 st.close();
44 conn.close();
45 }
46 }
47 }
1 import java.sql.*;
2
3 public class TransactionDemo1 {
4 public static void main(String[] args) throws SQLException, ClassNotFoundException {
5 String url = "jdbc:mysql://localhost/xh";
6 String username = "xiaohengdada";
7 String password = "123456";
8
9 Class.forName("org.gjt.mm.mysql.Driver");
10 Connection conn = null;
11 PreparedStatement st = null;
12 ResultSet rs = null;
13
14 try {
15 conn = DriverManager.getConnection(url, username, password);
16 conn.setAutoCommit(false);// 通知数据库开启事务(start transaction)
17 String sql1 = "update account set money=money-100 where name=‘A‘";
18 st = conn.prepareStatement(sql1);
19 st.executeUpdate();
20 // 用这句代码模拟执行完SQL1之后程序出现了异常而导致后面的SQL无法正常执行，事务也无法正常提交，此时数据库会自动执行回滚操作
21 int x = 1 / 0;
22 String sql2 = "update account set money=money+100 where name=‘B‘";
23 st = conn.prepareStatement(sql2);
24 st.executeUpdate();
25 conn.commit();// 上面的两条SQL执行Update语句成功之后就通知数据库提交事务(commit)
26 System.out.println("成功！！！");
27 } catch (Exception e) {
28 e.printStackTrace();
29 } finally {
30 st.close();
31 conn.close();
32 }
33 }
34 }
1 import java.sql.*;
2
3 public class TransactionDemo1 {
4 public static void main(String[] args) throws SQLException, ClassNotFoundException {
5 String url = "jdbc:mysql://localhost/xh";
6 String username = "xiaohengdada";
7 String password = "123456";
8
9 Class.forName("org.gjt.mm.mysql.Driver");
10 Connection conn = null;
11 PreparedStatement st = null;
12 ResultSet rs = null;
13
14 try{
15 conn = DriverManager.getConnection(url,username,password);
16 conn.setAutoCommit(false);//通知数据库开启事务(start transaction)
17 String sql1 = "update account set money=money-100 where name=‘A‘";
18 st = conn.prepareStatement(sql1);
19 st.executeUpdate();
20 //用这句代码模拟执行完SQL1之后程序出现了异常而导致后面的SQL无法正常执行，事务也无法正常提交
21 int x = 1/0;
22 String sql2 = "update account set money=money+100 where name=‘B‘";
23 st = conn.prepareStatement(sql2);
24 st.executeUpdate();
25 conn.commit();//上面的两条SQL执行Update语句成功之后就通知数据库提交事务(commit)
26 System.out.println("成功！！！");
27 }catch (Exception e) {
28 try {
29 //捕获到异常之后手动通知数据库执行回滚事务的操作
30 conn.rollback();
31 } catch (SQLException e1) {
32 e1.printStackTrace();
33 }
34 e.printStackTrace();
35 }finally{
36
37 }
38 }
39 }
设置回滚点：
1 import java.sql.*;
2
3 public class TransactionDemo1 {
4 public static void main(String[] args) throws SQLException, ClassNotFoundException {
5 String url = "jdbc:mysql://localhost/xh";
6 String username = "xiaohengdada";
7 String password = "123456";
8
9 Class.forName("org.gjt.mm.mysql.Driver");
10 Connection conn = null;
11 PreparedStatement st = null;
12 ResultSet rs = null;
13 Savepoint sp = null;
14
15 try {
16 conn = DriverManager.getConnection(url, username, password);
17 conn.setAutoCommit(false);// 通知数据库开启事务(start transaction)
18
19 String sql1 = "update account set money=money-100 where name=‘A‘";
20 st = conn.prepareStatement(sql1);
21 st.executeUpdate();
22
23 // 设置事务回滚点
24 // sp = conn.setSavepoint();
25
26 String sql2 = "update account set money=money+100 where name=‘B‘";
27 st = conn.prepareStatement(sql2);
28 st.executeUpdate();
29
30 sp = conn.setSavepoint();
31 // 程序执行到这里出现异常，后面的sql3语句执行将会中断
32 int x = 1 / 0;
33
34 String sql3 = "update account set money=money+100 where name=‘C‘";
35 st = conn.prepareStatement(sql3);
36 st.executeUpdate();
37
38 conn.commit();
39
40 } catch (Exception e) {
41 try {
42 /**
43 * 我们在上面向数据库发送了3条update语句， sql3语句由于程序出现异常导致无法正常执行，数据库事务而已无法正常提交，
44 * 由于设置的事务回滚点是在sql1语句正常执行完成之后，sql2语句正常执行之前,
45 * 那么通知数据库回滚事务时，不会回滚sql1执行的update操作
46 * 只会回滚到sql2执行的update操作，也就是说，上面的三条update语句中，sql1这条语句的修改操作起作用了
47 * sql2的修改操作由于事务回滚没有起作用，sql3由于程序异常没有机会执行
48 */
49 conn.rollback(sp);// 回滚到设置的事务回滚点
50 // 回滚了要记得通知数据库提交事务
51 conn.commit();
52 } catch (SQLException e1) {
53 e1.printStackTrace();
54 }
55 e.printStackTrace();
56 } finally {
57 }
58 }
59 }
时间： 2024-10-29 19:09:47