(一)
@Transactional(isolation = Isolation.READ_COMMITTED)
public Object listForIllusionRead() {
List
会话1执行listForIllusionRead,第一次读
会话1sleep阻塞
会话2执行update有效会话操作
会话1第二次读
会话1返回
{ "before":[ { "col1":1, "col2":"d" } ], "after":[ { "col1":1, "col2":"e" } ]}
结论:与理论相符,两次读取不一样
(二)
@Transactional(isolation = Isolation.REPEATABLE_READ)
public Object listForIllusionRead() {
List> map = jdbcTemplate.queryForList("select * from tao");
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
List> map2 = jdbcTemplate.queryForList("select * from tao");
Map res = new HashMap();
res.put("before", map);
res.put("after", map2);
return res;
}
public void updateForNoRepeat () {
jdbcTemplate.execute("update tao set col2 = 'e'");
}
会话1执行listForIllusionRead,第一次读
会话1sleep阻塞
会话2执行update有效会话操作
会话1第二次读
会话1返回
{ " before ": [ { "col1":1, "col2":"d" } ] , " after ": [ { "col1":1, "col2":"d" } ]}结论:
结论:与理论相符,同一个会话的两次读取一样,为修改前的
(三)
@Transactional(isolation = Isolation.READ_COMMITTED)
public Object listForIllusionRead() {
List> map = jdbcTemplate.queryForList("select * from tao");
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
List> map2 = jdbcTemplate.queryForList("select * from tao");
Map res = new HashMap();
res.put("before", map);
res.put("after", map2);
return res;
}
public void updateForNoRepeat () {
jdbcTemplate.execute("update tao set col2 = 'e'");
}
public void deleteForNoRepeat() {
jdbcTemplate.execute("delete from tao ");
}
会话1执行listForIllusionRead,第一次读
会话1sleep阻塞
会话2执行delete有效会话操作
会话1第二次读
会话1返回
{ " before ": [ { "col1":1, "col2":"e" } ] , " after ": []}结论:与理论相符,两次读取不一样
(四)
@Transactional(isolation = Isolation.REPEATABLE_READ)
public Object listForIllusionRead() {
List> map = jdbcTemplate.queryForList("select * from tao");
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
List> map2 = jdbcTemplate.queryForList("select * from tao");
Map res = new HashMap();
res.put("before", map);
res.put("after", map2);
return res;
}
public void updateForNoRepeat () {
jdbcTemplate.execute("update tao set col2 = 'e'");
}
public void deleteForNoRepeat() {
jdbcTemplate.execute("delete from tao ");
}
会话1执行listForIllusionRead,第一次读
会话1sleep阻塞
会话2执行delete有效会话操作
会话1第二次读
会话1返回
{ " before ": [ { "col1":1, "col2":"d" } ] , " after ": [ { "col1":1, "col2":"d" } ]}结论:与理论相符,两次读取一样,为删除前的
修改方 查询方
thread A B
transcation off on(为了定义隔离级别,也为了定义为一次会话)
isolation not care read-commited
有重复读
修改方 查询方
thread A B
transcation off on(为了定义隔离级别,也为了定义为一次会话)
isolation not care repeatable_read
无重复读
修改方 查询方
thread A B
transcation off on(为了定义隔离级别,也为了定义为一次会话)
isolation not care read-commited
有重复读
修改方 查询方
thread A B
transcation off on(为了定义隔离级别,也为了定义为一次会话)
isolation not care repeatable_read