java通过反射拿到mybatis中的sql语句并操作

private static final int MaxBatchLength = 100;

public void updateBatch(List<T>list, BaseMapper<T> mapper){ if (!Proxy.isProxyClass(mapper.getClass())){
throw new RuntimeException("mapper必须是代理对象");
}
InvocationHandler invocationHandler = Proxy.getInvocationHandler(mapper);
if (null==invocationHandler){
throw new RuntimeException("mapper必须是有处理器的代理对象");
}
Field fieldSession;
try {
fieldSession = invocationHandler.getClass().getDeclaredField("sqlSession");
} catch (NoSuchFieldException e) {
throw new RuntimeException("从mapper代理对象中获取不到sqlSession", e);
}
Field fieldMapper;
try {
fieldMapper = invocationHandler.getClass().getDeclaredField("mapperInterface");
} catch (NoSuchFieldException | SecurityException e) {
throw new RuntimeException("从mapper代理对象中获取不到mapperInterface", e);
}
fieldSession.setAccessible(true);
SqlSession session;
try {
session = (SqlSession) fieldSession.get(invocationHandler);
} catch (IllegalArgumentException | IllegalAccessException e) {
throw new RuntimeException("从mapper代理对象中获取sqlSession失败，不应该出现此异常", e);
}
fieldMapper.setAccessible(true);
Class<?> mapperInterface;
try {
mapperInterface = (Class<?>) fieldMapper.get(invocationHandler);
} catch (IllegalArgumentException | IllegalAccessException e) {
throw new RuntimeException("从mapper代理对象中获取mapperInterface失败，不应该出现此异常", e);
}
// 方法名(mybatis的对应xml中的sql语句的id)
String methodName = mapperInterface.getName() + ".updateEntityBatch";
System.out.println("获取方法的SQL："+methodName);
//传递参数保证，要更新的字段存在（若没有判空，则可以不用传递参数）
BoundSql boundSql = session.getConfiguration().getMappedStatement(methodName).getBoundSql(list.get(0)); //是否是独立的事务
boolean atmo = true, succ = false;
System.out.println("每次批量执行最大长度为："+MaxBatchLength ); //获取批量执行的sql
String sql = boundSql.getSql();
//获取连接
Connection connection = null;
PreparedStatement ps = null;
List<Closeable> closeables = new LinkedList<>();
try {
connection = session.getConnection();
if (atmo = null == connection || connection.isClosed()) {
DataSource dataSource = session.getConfiguration().getEnvironment().getDataSource();
connection = dataSource.getConnection();
//事务不自动提交
connection.setAutoCommit(false);
System.out.println("session中的连接不可使用，使用独立的连接和事务");
} else {
System.out.println("使用session的连接，事务和session保持一致");
} ps = connection.prepareStatement(sql); int index = 0;
System.out.println("需要批量更新"+list.size()+"个对象"); for (int i = 0, j = list.size(); i < j; i++, index++) {
T t = list.get(i);
//将实体类转换为map
BeanMap map = BeanMap.create(t);
System.out.println("绑定对象:"+ map);
for (int ii = 1, jj = boundSql.getParameterMappings().size(); ii <= jj; ii++) {
ParameterMapping parameterMapping = boundSql.getParameterMappings().get(ii - 1);
String name = parameterMapping.getProperty();
Object value = map.get(name);
if (null == value) {
// 为空时候尝试取默认值
value = map.get(name + "Default");
}
if (null != value && value instanceof Date) {
Timestamp date = new Timestamp(((Date) value).getTime());
value = date;
}
// 单独处理clob类型
if (JdbcType.CLOB.equals(parameterMapping.getJdbcType())) {
StringReader sr = new StringReader(null == value ? "" : value.toString());
ps.setClob(ii, sr);
closeables.add(sr);
} else {
ps.setObject(ii, value, parameterMapping.getJdbcType().TYPE_CODE);
}
}
ps.addBatch();
if (index > MaxBatchLength) {
ps.executeBatch();
ps.clearBatch();
index = 0;
}
}
if (index > 0) {
//执行剩下的
ps.executeBatch();
}
succ = true;
}catch (Exception e){
throw new RuntimeException("批量更新失败",e);
}finally {
// 如果是独立的事务
if (atmo && null != connection) {
log.info("检测到独立事务，判断提交/回滚");
if (succ) {
try {
connection.commit();
log.info("独立事务提交成功");
} catch (SQLException e) {
log.info("独立事务提交失败");
throw new RuntimeException(e);
}
} else {
try {
connection.rollback();
log.info("独立事务回滚成功");
} catch (SQLException e) {
log.info("独立事务回滚失败");
throw new RuntimeException(e);
}
}
}
if (null != ps) {
try {
ps.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (atmo && null != connection) {
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
for (Closeable closeable : closeables) {
try {
closeable.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}