sql解析,转换列表和表名
1、 jsqlparse介绍
JSqlParse是一款很精简的sql解析工具,它可以将常用的sql文本解析成具有层级结构的"语法树",我们可以针对解析后的"树节点(也即官网里说的有层次结构的java类)"进行处理进而生成符合我们要求的sql形式。
官网给的介绍很简洁:JSqlParser 解析 SQL 语句并将其转换为 Java 类的层次结构。生成的层次结构可以使用访问者模式进行访问(官网地址:JSqlParser - Home)。
2 pom坐标
<dependency>
<groupId>com.github.jsqlparser</groupId>
<artifactId>jsqlparser</artifactId>
<version>4.3</version>
</dependency>
3 解析工具类
private static String convertSql(String sql, Class<?> clazz) throws Exception {
Select select = (Select) CCJSqlParserUtil.parse(sql);
SelectBody selectBody = select.getSelectBody();
if (selectBody instanceof PlainSelect) {
PlainSelect plainSelect = (PlainSelect) selectBody;
Table table = (Table) plainSelect.getFromItem();
String originTableName = table.getName().toLowerCase();
Matcher matcher = pattern.matcher(originTableName);
//如果不符合原来的的表名格式就返回原sql
if (!matcher.find()) {
return sql;
}
String day = matcher.group().replace("_", "-");
long start = 0;
long end = 10;
//转换where条件
Expression where = plainSelect.getWhere();
where.accept(new MyWhereExpressionVisitorAdapter());
// 不管原来有没有时间条件,都拼接上当天的时间条件
String condExpr = where + " and time >= " + start + " and time <= " + end;
Expression newCondition = CCJSqlParserUtil.parseCondExpression(condExpr);
plainSelect.setWhere(newCondition);
//设置表名
TableName annotation = clazz.getAnnotation(TableName.class);
table.setName(annotation.value());
//转换select的列
for (SelectItem selectItem : plainSelect.getSelectItems()) {
SelectExpressionItem item = (SelectExpressionItem) selectItem;
item.accept(new MySelectExpressionVisitorAdapter(item, KEY_MAP.get(clazz)));
}
}
//加时间排序
return select + " order by time asc";
}
3 列名转换
public class MySelectExpressionVisitorAdapter extends ExpressionVisitorAdapter {
private SelectExpressionItem item;
private Map<String, String> columnMap;
public MySelectExpressionVisitorAdapter(SelectExpressionItem item, Map<String, String> columnMap) {
this.item = item;
this.columnMap = columnMap;
}
@Override
public void visit(Column column) {
Expression expression = item.getExpression();
String originColumnName = column.getColumnName();
String changeColumnName = columnMap.get(originColumnName.toUpperCase());
if (changeColumnName != null) {
column.setColumnName(changeColumnName);
//把原列名当做别名
if (!originColumnName.equals(changeColumnName) && expression instanceof Column && item.getAlias() == null) {
item.setAlias(new Alias(originColumnName));
}
}
}
@Override
public void visit(Function function) {
String name = function.getName();
if ("round".equalsIgnoreCase(name)) {
function.getParameters().getExpressions().remove(1);
function.setName("");
}
super.visit(function);
}
4 条件转换
public class MyWhereExpressionVisitorAdapter extends ExpressionVisitorAdapter {
@Override
protected void visitBinaryExpression(BinaryExpression expression) {
if (!(expression instanceof ComparisonOperator)) {
super.visitBinaryExpression(expression);
return;
}
Column column = (Column) expression.getLeftExpression();
String columnName = column.getColumnName();
if ("isAgain".equalsIgnoreCase(columnName)) {
column.setColumnName("isAgain");
Expression rightExpression = expression.getRightExpression();
if (rightExpression instanceof LongValue) {
LongValue tmp = (LongValue) rightExpression;
tmp.setStringValue(String.valueOf(tmp.getValue()>0));
}
} else if ("time".equalsIgnoreCase(columnName)) {
column.setColumnName("time");
changeTime((ComparisonOperator) expression);
} else if (changeWhereSerialColumName(columnName)) {
column.setColumnName("serialNum");
}
}
/**
* 转换时间条件列
* @param comparisonOperator
*/
private void changeTime(ComparisonOperator comparisonOperator) {
Expression rightExpression = comparisonOperator.getRightExpression();
if (rightExpression instanceof StringValue) {
long value = DateTimeUtilJdk8.getTimeMilli(((StringValue) rightExpression).getValue());
LongValue longValue = new LongValue();
longValue.setValue(value);
comparisonOperator.setRightExpression(longValue);
}
}
private boolean changeWhereSerialColumName(String column) {
return LindormUtil.getOriginalSerialNumName().contains(column.toUpperCase());
}
测试
public static void main(String[] args) throws Exception {
String sql = "select ID, username,password from Tbl_db_2023_06_26 where id='007'";
System.out.println(convertSql(sql, Object.class));
}