- SqlParser - github位址:https://github.com/JSQLParser/JSqlParser
- SqlParser最新版jar下載下傳:http://search.maven.org/remotecontent?filepath=com/github/jsqlparser/jsqlparser/0.9.1/jsqlparser-0.9.1.jar
前面有一篇部落格介紹了另一個fdb-sql-parser的簡單使用。由于fdb-sql-parser針對性比較強,對不同資料庫的通用性不好,是以嘗試了另一個sql解析工具jsqlparser。
在jsqlparser的wiki頁面有簡單的使用方法:https://github.com/JSQLParser/JSqlParser/wiki
這裡仍然用去除order by做例子。
jsqlparser的資料結構比較簡單,更清晰,因而我選擇了一種正向強制設定order by屬性為null的方式來去除order by
下面是需要用到的幾個方法:
public String removeOrderBy(String sql) throws JSQLParserException {
Statement stmt = CCJSqlParserUtil.parse(sql);
Select select = (Select) stmt;
SelectBody selectBody = select.getSelectBody();
processSelectBody(selectBody);
return select.toString();
}
public void processSelectBody(SelectBody selectBody) {
if (selectBody instanceof PlainSelect) {
processPlainSelect((PlainSelect) selectBody);
} else if (selectBody instanceof WithItem) {
WithItem withItem = (WithItem) selectBody;
if (withItem.getSelectBody() != null) {
processSelectBody(withItem.getSelectBody());
}
} else {
SetOperationList operationList = (SetOperationList) selectBody;
if (operationList.getPlainSelects() != null && operationList.getPlainSelects().size() > 0) {
List<PlainSelect> plainSelects = operationList.getPlainSelects();
for (PlainSelect plainSelect : plainSelects) {
processPlainSelect(plainSelect);
}
}
if (!orderByHashParameters(operationList.getOrderByElements())) {
operationList.setOrderByElements(null);
}
}
}
public void processPlainSelect(PlainSelect plainSelect) {
if (!orderByHashParameters(plainSelect.getOrderByElements())) {
plainSelect.setOrderByElements(null);
}
if (plainSelect.getFromItem() != null) {
processFromItem(plainSelect.getFromItem());
}
if (plainSelect.getJoins() != null && plainSelect.getJoins().size() > 0) {
List<Join> joins = plainSelect.getJoins();
for (Join join : joins) {
if (join.getRightItem() != null) {
processFromItem(join.getRightItem());
}
}
}
}
public void processFromItem(FromItem fromItem) {
if (fromItem instanceof SubJoin) {
SubJoin subJoin = (SubJoin) fromItem;
if (subJoin.getJoin() != null) {
if (subJoin.getJoin().getRightItem() != null) {
processFromItem(subJoin.getJoin().getRightItem());
}
}
if (subJoin.getLeft() != null) {
processFromItem(subJoin.getLeft());
}
} else if (fromItem instanceof SubSelect) {
SubSelect subSelect = (SubSelect) fromItem;
if (subSelect.getSelectBody() != null) {
processSelectBody(subSelect.getSelectBody());
}
} else if (fromItem instanceof ValuesList) {
} else if (fromItem instanceof LateralSubSelect) {
LateralSubSelect lateralSubSelect = (LateralSubSelect) fromItem;
if (lateralSubSelect.getSubSelect() != null) {
SubSelect subSelect = (SubSelect) (lateralSubSelect.getSubSelect());
if (subSelect.getSelectBody() != null) {
processSelectBody(subSelect.getSelectBody());
}
}
}
//Table時不用處理
}
public boolean orderByHashParameters(List<OrderByElement> orderByElements) {
if (orderByElements == null) {
return false;
}
for (OrderByElement orderByElement : orderByElements) {
if (orderByElement.toString().toUpperCase().contains("?")) {
return true;
}
}
return false;
}
由于jsqlparser結構簡單,繼承也不複雜,并且setter和getter方法很全面,是以處理起來很容易。