private void pagination(Invocation invocation, StatementHandler target) throws SQLException {
final MetaObject metaStatementHandler = getMetaObject(target);
final BoundSql boundSql = target.getBoundSql();
Page<?> page = PAGE_THREAD_LOCAL.get();
if (page == null) {
page = findPageParameter(boundSql.getParameterObject());
}
// 如果传入的参数中有分页对象且sql语句中有select，才做分页处理
String sql = boundSql.getSql().toLowerCase();
if (sql.startsWith("select") && page != null) {
// 采用物理分页后，就不需要mybatis的内存分页了，所以重置下面的两个参数
metaStatementHandler.setValue("delegate.rowBounds.offset", RowBounds.NO_ROW_OFFSET);
metaStatementHandler.setValue("delegate.rowBounds.limit", RowBounds.NO_ROW_LIMIT);
// 设置分页对象里的总记录数和总页数
Connection connection = (Connection) invocation.getArgs()[0];
MappedStatement mappedStatement =
(MappedStatement) metaStatementHandler.getValue("delegate.mappedStatement");
if (page.isCountTotal()) {
int recordsTotal = getTotalCount(sql, connection, mappedStatement, boundSql);
page.setTotalNum(recordsTotal);
}
// 最后重写sql
String pageSql = buildPageSql(sql, page);
metaStatementHandler.setValue("delegate.boundSql.sql", pageSql);
}
}
@SuppressWarnings({"rawtypes", "unchecked"})
private void autoMap(Invocation invocation, String name) throws ClassNotFoundException {
final Object[] queryArgs = invocation.getArgs();
final MappedStatement ms = (MappedStatement) queryArgs[0];
final Object parameter = queryArgs[1];
String statementId = ms.getId();
MapperMeta meta = getMapperMeta(ms.getConfiguration(), statementId);
if (meta.isFillEntity()) {
// 将泛型类加入到参数中供CrudTemplate使用
if (parameter != null) {
Map map;
if (parameter instanceof Map) {
map = (HashMap) parameter;
map.put(CrudProvider.CLASS_KEY, meta.getEntity());
} else {
map = new HashMap();
map.put(CrudProvider.PARA_KEY, parameter);
map.put(CrudProvider.CLASS_KEY, meta.getEntity());
}
queryArgs[1] = map;
} else {
queryArgs[1] = meta.getEntity();
}
}
if (meta.isFillResultMap()) {
MetaObject metaMappedStatement = getMetaObject(ms);
metaMappedStatement.setValue("resultMaps", meta.getResultMaps());
}
if (name.equals("query")) {
final RowBounds rowBounds = (RowBounds) queryArgs[2];
if (rowBounds == null || rowBounds == RowBounds.DEFAULT) {
Page p = findPageParameter(queryArgs[1]);
if (p != null) {
queryArgs[2] = new RowBounds(p.getOffset(), p.getLimit());
}
}
}
}
public Object doPage(Invocation invocation) throws Throwable {
log.debug("进入Executor");
final Object[] args = invocation.getArgs();
RowBounds rowBounds = (RowBounds) args[2];
PageParam pageParam = null; // PageContextHolder.get();
if (args[1] instanceof MapperMethod.ParamMap<?>) {
MapperMethod.ParamMap<?> map = (MapperMethod.ParamMap<?>) args[1];
for (String key : map.keySet()) {
if (key.startsWith("param")) {
Object obj = map.get(key);
if (obj instanceof PageParam) {
pageParam = (PageParam) obj;
} else if (args[1] instanceof MapperMethod.ParamMap<?>) {
args[1] = obj;
}
}
}
}
// 无分页参数
if (pageParam == null) {
log.debug("默认查询");
return invocation.proceed();
}
log.debug("分页查询");
PageWrapper page = new PageWrapper();
MappedStatement ms = (MappedStatement) args[0];
args[2] = RowBounds.DEFAULT;
// 无需分页
if (pageParam.getPageSize() == 0) {
log.debug("全量查询");
Object result = invocation.proceed();
page.addAll((List) result);
page.setPageNo(1);
page.setPageSize(page.size());
page.setTotalPage(1);
page.setTotalCount(page.size());
return page;
}
SqlSource sqlSource = ((MappedStatement) args[0]).getSqlSource();
dialect = DialectFactory.buildDialect(ms.getConfiguration());
// 需总数
args[0] = getMappedStatement(ms, sqlSource, args[1], Const.CACHE_KEY_COUNT, MappingEnum.INT);
Object resultCount = invocation.proceed();
int totalCount = ((Integer) ((List) resultCount).get(0));
log.debug("总条数查询为 {}", totalCount);
page.setTotalCount(totalCount);
page.setPageNo(pageParam.getPageNo());
page.setPageSize(pageParam.getPageSize());
// 提升效率：count为0不再分页查
if (page.getTotalCount() == 0) {
return page;
}
// 需分页
// 便捷查询：pageSize<=0 仅查询count
if (pageParam.getPageSize() > 0) {
args[0] =
getMappedStatement(ms, sqlSource, args[1], Const.CACHE_KEY_PAGE, MappingEnum.DEFAULT);
args[1] = setParameter((MappedStatement) args[0], args[1], pageParam, dialect);
Object result = invocation.proceed();
page.addAll((List) result);
log.debug("分页查询结束 {}", pageParam);
}
return page;
}
