JSqlParser簡單使用小記

項目計划采用數據權限控制，擬采用mybatis加JSqlParser做sql攔截和處理，因此研究了一下JSqlParser的使用，如下：
1. select語句查詢字段

public static List<String> test_select_items(String sql)
            throws JSQLParserException {
        CCJSqlParserManager parserManager = new CCJSqlParserManager();
        Select select = (Select) parserManager.parse(new StringReader(sql));
        PlainSelect plain = (PlainSelect) select.getSelectBody();
　　　　　//普通查詢，查詢所有字段
        List<SelectItem> selectitems = plain.getSelectItems();
        List<String> str_items = new ArrayList<String>();
        if (selectitems != null) {
            for (int i = 0; i < selectitems.size(); i++) {
                str_items.add(selectitems.get(i).toString());
            }
        }
        return str_items;
    }

2.獲取表名，注：調用此方法，顯示的表名為去重后的表名

public static List<String> test_select_table(String sql)
            throws JSQLParserException {
        Statement statement = (Statement) CCJSqlParserUtil.parse(sql);
        Select selectStatement = (Select) statement;
　　　　//獲取表名
        TablesNamesFinder tablesNamesFinder = new TablesNamesFinder();
        List<String> tableList = tablesNamesFinder
                .getTableList(selectStatement);
        return tableList;
    }

3. 獲取關聯關系

public static List<String> test_select_join(String sql)
            throws JSQLParserException {
        Statement statement = (Statement) CCJSqlParserUtil.parse(sql);
        Select selectStatement = (Select) statement;
        PlainSelect plain = (PlainSelect) selectStatement.getSelectBody();
        List<Join> joinList = plain.getJoins();
        List<String> tablewithjoin = new ArrayList<String>();
        if (joinList != null) {
　　　　　　　//如果關聯后面是子查詢，可以通過便利join集合，獲取FromItem rightItem = join.getRightItem();
　　　　　　　　//判斷fromItem屬於哪種類型，如果是subSelect類型就是子查詢

        for (int i = 0; i < joinList.size(); i++) { 
          tablewithjoin.add(joinList.get(i).toString()); 

          //注意 ， leftjoin rightjoin 等等的to string()區別  
        }
 　　} 

　　return tablewithjoin; 
}

4. 查詢where

public static String test_select_where(String sql)
            throws JSQLParserException {
        String columnNames = null;
        String allColumnNames = null;

        CCJSqlParserManager parserManager = new CCJSqlParserManager();
        Select select = (Select) parserManager.parse(new StringReader(sql));
        PlainSelect plain = (PlainSelect) select.getSelectBody();
        Expression where_expression = plain.getWhere();
        String str = null;
        if (where_expression != null) {
            /*str = where_expression.toString();
            ExpressionVisitorImpl expressionVisitor = new ExpressionVisitorImpl();
            where_expression.accept(expressionVisitor);*/
            Set<String> sets = getParser(where_expression);
            StringBuffer st = new StringBuffer();
            sets.stream().forEach(set -> {
                st.append(set + ",");
            });
        }
        return str;
    }

private static Set<String> getParser(Expression expression) {
    //初始化接受獲得的字段信息
    if (expression instanceof BinaryExpression) {
        //獲得左邊表達式
        Expression leftExpression = ((BinaryExpression) expression).getLeftExpression();
        //獲得左邊表達式為Column對象，則直接獲得列名
        if (leftExpression instanceof Column) {
            columnName = ((Column) leftExpression).getColumnName();
            set.add(columnName);
        } else if (leftExpression instanceof InExpression) {
            parserInExpression(leftExpression);
        } else if (leftExpression instanceof IsNullExpression) {
            parserIsNullExpression(leftExpression);
        } else if (leftExpression instanceof BinaryExpression) {//遞歸調用
            getParser(leftExpression);
        } else if (expression instanceof Parenthesis) {//遞歸調用
            Expression expression1 = ((Parenthesis) expression).getExpression();
            getParser(expression1);
        }

        //獲得右邊表達式，並分解
        Expression rightExpression = ((BinaryExpression) expression).getRightExpression();
        if (rightExpression instanceof BinaryExpression) {
            parserBinaryExpression(rightExpression);
        } else if (rightExpression instanceof InExpression) {
            parserInExpression(rightExpression);
        } else if (rightExpression instanceof IsNullExpression) {
            parserIsNullExpression(rightExpression);
        } else if (rightExpression instanceof Parenthesis) {//遞歸調用
            Expression expression1 = ((Parenthesis) rightExpression).getExpression();
            getParser(expression1);
        }
    } else if (expression instanceof InExpression) {
        parserInExpression(expression);
    } else if (expression instanceof IsNullExpression) {
        parserIsNullExpression(expression);
    } else if (expression instanceof Parenthesis) {//遞歸調用
        Expression expression1 = ((Parenthesis) expression).getExpression();
        getParser(expression1);
    }
    return set;
}

/**
 * 解析in關鍵字左邊的條件
 *
 * @param expression
 */
public static void parserInExpression(Expression expression) {
    Expression leftExpression = ((InExpression) expression).getLeftExpression();
    if (leftExpression instanceof Column) {
        columnName = ((Column) leftExpression).getColumnName();
        set.add(columnName);
    }
}

/**
 * 解析is null 和 is not null關鍵字左邊的條件
 *
 * @param expression
 */
public static void parserIsNullExpression(Expression expression) {
    Expression leftExpression = ((IsNullExpression) expression).getLeftExpression();
    if (leftExpression instanceof Column) {
        columnName = ((Column) leftExpression).getColumnName();
        set.add(columnName);
    }
}

public static void parserBinaryExpression(Expression expression) {
    Expression leftExpression = ((BinaryExpression) expression).getLeftExpression();
    if (leftExpression instanceof Column) {
        columnName = ((Column) leftExpression).getColumnName();
        set.add(columnName);
    }
}

5. 獲取from ，如果from關鍵字后面是子查詢語句，則遞歸調用原處理語句

private static String test_select_from(String sql) throws JSQLParserException {
        CCJSqlParserManager parserManager = new CCJSqlParserManager();
        Select select = (Select) parserManager.parse(new StringReader(sql));
        // 訪問from
        PlainSelect plain = (PlainSelect) select.getSelectBody();
        // 訪問from
        FromItem fromItem = plain.getFromItem();
        if (fromItem instanceof SubSelect) {
            System.out.println("-----------------子查詢開始-----------------");
            SelectBody selectBody = ((SubSelect) fromItem).getSelectBody();
            System.out.println("子查詢"+selectBody.toString());
            test_select(selectBody.toString());
            System.out.println("-----------------子查詢結束-----------------");
        }
        return fromItem.toString();
    }

6.整體執行語句如下：

public static void test_select(String sql) throws JSQLParserException {
        // *********select body items內容
        List<String> str_items = Prasing_Test.test_select_items(sql);
        System.out.println("查詢字段為："+str_items.toString());

        // **********select table
        List<String> tableList = Prasing_Test.test_select_table(sql);
        System.out.println("表名為："+tableList.toString());

        String fromTable = Prasing_Test.test_select_from(sql);
        System.out.println("from 表名："+fromTable);
        // **********select table with join
        List<String> tablewithjoin = Prasing_Test.test_select_join(sql);
        for (String join:tablewithjoin) {
            System.out.println("連接方式為："+join);
        }

        // // *******select where
        String str = Prasing_Test.test_select_where(sql);
        System.out.println("where 條件"+str);
        // // ******select group by
        List<String> str_groupby = Prasing_Test.test_select_groupby(sql);
        System.out.println("group by 字段為："+str_groupby.toString());
        // //**************select order by
        List<String> str_orderby = Prasing_Test.test_select_orderby(sql);
        System.out.println("order by 條件為："+str_orderby.toString());
    }

后續補充。