Java：解析sql语句的一个开源项目

有时候一些数据不支持sql语句，那么我们为了使其应用更加方便，sql语句可以在接口中包装一下，自己写parser太复杂，工作量不小，这里有一个开源的项目可以帮助我们做这个事情。

http://jsqlparser.sourceforge.net/example.php

Example: a tables names finder

With this example class you can easily get the list of tables in a select statement (including subqueries and joins and, as soon as the union code will be ready, unions)

  
public class TablesNamesFinder implements SelectVisitor, FromItemVisitor, JoinVisitor, ExpressionVisitor, ItemsListVisitor {
	private List tables;

	public List getTableList(Select select) {
		tables = new ArrayList();
		select.getSelectBody().accept(this);
		return tables;
	}

	public void visit(PlainSelect plainSelect) {
		plainSelect.getFromItem().accept(this);
		
		if (plainSelect.getJoins() != null) {
			for (Iterator joinsIt = plainSelect.getJoins().iterator(); joinsIt.hasNext();) {
				Join join = (Join) joinsIt.next();
				join.getRightItem().accept(this);
			}
		}
		if (plainSelect.getWhere() != null)
			plainSelect.getWhere().accept(this);

	}

	public void visit(Union union) {
		for (Iterator iter = union.getPlainSelects().iterator(); iter.hasNext();) {
			PlainSelect plainSelect = (PlainSelect) iter.next();
			visit(plainSelect);
		}
	}

	public void visit(Table tableName) {
		String tableWholeName = tableName.getWholeTableName();
		tables.add(tableWholeName);
	}

	public void visit(SubSelect subSelect) {
		subSelect.getSelectBody().accept(this);
	}

	public void visit(Addition addition) {
		visitBinaryExpression(addition);
	}

	public void visit(AndExpression andExpression) {
		visitBinaryExpression(andExpression);
	}

	public void visit(Between between) {
		between.getLeftExpression().accept(this);
		between.getBetweenExpressionStart().accept(this);
		between.getBetweenExpressionEnd().accept(this);
	}

	public void visit(Column tableColumn) {
	}

	public void visit(Division division) {
		visitBinaryExpression(division);
	}

	public void visit(DoubleValue doubleValue) {
	}

	public void visit(EqualsTo equalsTo) {
		visitBinaryExpression(equalsTo);
	}

	public void visit(Function function) {
	}

	public void visit(GreaterThan greaterThan) {
		visitBinaryExpression(greaterThan);
	}

	public void visit(GreaterThanEquals greaterThanEquals) {
		visitBinaryExpression(greaterThanEquals);
	}

	public void visit(InExpression inExpression) {
		inExpression.getLeftExpression().accept(this);
		inExpression.getItemsList().accept(this);
	}

	public void visit(InverseExpression inverseExpression) {
		inverseExpression.getExpression().accept(this);
	}

	public void visit(IsNullExpression isNullExpression) {
	}

	public void visit(JdbcParameter jdbcParameter) {
	}

	public void visit(LikeExpression likeExpression) {
		visitBinaryExpression(likeExpression);
	}

	public void visit(ExistsExpression existsExpression) {
		existsExpression.getRightExpression().accept(this);
	}

	public void visit(LongValue longValue) {
	}

	public void visit(MinorThan minorThan) {
		visitBinaryExpression(minorThan);
	}

	public void visit(MinorThanEquals minorThanEquals) {
		visitBinaryExpression(minorThanEquals);
	}

	public void visit(Multiplication multiplication) {
		visitBinaryExpression(multiplication);
	}

	public void visit(NotEqualsTo notEqualsTo) {
		visitBinaryExpression(notEqualsTo);
	}

	public void visit(NullValue nullValue) {
	}

	public void visit(OrExpression orExpression) {
		visitBinaryExpression(orExpression);
	}

	public void visit(Parenthesis parenthesis) {
		parenthesis.getExpression().accept(this);
	}

	public void visit(StringValue stringValue) {
	}

	public void visit(Subtraction subtraction) {
		visitBinaryExpression(subtraction);
	}

	public void visitBinaryExpression(BinaryExpression binaryExpression) {
		binaryExpression.getLeftExpression().accept(this);
		binaryExpression.getRightExpression().accept(this);
	}

	public void visit(ExpressionList expressionList) {
		for (Iterator iter = expressionList.getExpressions().iterator(); iter.hasNext();) {
			Expression expression = (Expression) iter.next();
			expression.accept(this);
		}

	}

	public void visit(DateValue dateValue) {
	}
	
	public void visit(TimestampValue timestampValue) {
	}
	
	public void visit(TimeValue timeValue) {
	}

	public void visit(CaseExpression caseExpression) {
	}

	public void visit(WhenClause whenClause) {
	}

	public void visit(AllComparisonExpression allComparisonExpression) {
		allComparisonExpression.GetSubSelect().getSelectBody().accept(this);
	}

	public void visit(AnyComparisonExpression anyComparisonExpression) {
		anyComparisonExpression.GetSubSelect().getSelectBody().accept(this);
	}

	public void visit(SubJoin subjoin) {
		subjoin.getLeft().accept(this);
		subjoin.getJoin().getRightItem().accept(this);
	}

}

Code using TablesNamesFinder:

  
[..]
CCJSqlParserManager pm = new CCJSqlParserManager();
String sql = "SELECT * FROM MY_TABLE1, MY_TABLE2, (SELECT * FROM MY_TABLE3) LEFT OUTER JOIN MY_TABLE4 "+
" WHERE ID = (SELECT MAX(ID) FROM MY_TABLE5) AND ID2 IN (SELECT * FROM MY_TABLE6)" ;
net.sf.jsqlparser.statement.Statement statement = pm.parse(new StringReader(sql));
/* 
now you should use a class that implements StatementVisitor to decide what to do
based on the kind of the statement, that is SELECT or INSERT etc. but here we are only
interested in SELECTS
*/
if (statement instanceof Select) {
	Select selectStatement = (Select) statement;
	TablesNamesFinder tablesNamesFinder = new TablesNamesFinder();
	List tableList = tablesNamesFinder.getTableList(selectStatement);
	for (Iterator iter = tableList.iterator(); iter.hasNext();) {
		System.out.println(tableName);
	}
}