一个利用正则表达式解析单句SQL的类SqlParser

先看要解析的样例SQL语句：
select * from dual
SELECT * frOm dual
Select C1,c2 From tb
select c1,c2 from tb
select count(*) from t1
select c1,c2,c3 from t1 where condi1=1
Select c1,c2,c3 From t1 Where condi1=1
select c1,c2,c3 from t1,t2 where condi3=3 or condi4=5 order by o1,o2
Select c1,c2,c3 from t1,t2 Where condi3=3 or condi4=5 Order by o1,o2
select c1,c2,c3 from t1,t2,t3 where condi1=5 and condi6=6 or condi7=7 group by g1,g2
Select c1,c2,c3 From t1,t2,t3 Where condi1=5 and condi6=6 or condi7=7 Group by g1,g2
Select c1,c2,c3 From t1,t2,t3 Where condi1=5 and condi6=6 or condi7=7 Group by g1,g2,g3 order by g2,g3

解析效果之一（isSingleLine=false）：
原SQL为select * from dual
解析后的SQL为
select
*
from
dual

原SQL为SELECT * frOm dual
解析后的SQL为
select
*
from
dual

原SQL为Select C1,c2 From tb
解析后的SQL为
select
C1,c2
from
tb

原SQL为select c1,c2 from tb
解析后的SQL为
select
c1,c2
from
tb

原SQL为select count(*) from t1
解析后的SQL为
select
count(*)
from
t1

原SQL为select c1,c2,c3 from t1 where condi1=1
解析后的SQL为
select
c1,c2,c3
from
t1
where
condi1=1

原SQL为Select c1,c2,c3 From t1 Where condi1=1
解析后的SQL为
select
c1,c2,c3
from
t1
where
condi1=1

原SQL为select c1,c2,c3 from t1,t2 where condi3=3 or condi4=5 order by o1,o2
解析后的SQL为
select
c1,c2,c3
from
t1,t2
where
condi3=3 or condi4=5
order by
o1,o2

原SQL为Select c1,c2,c3 from t1,t2 Where condi3=3 or condi4=5 Order by o1,o2
解析后的SQL为
select
c1,c2,c3
from
t1,t2
where
condi3=3 or condi4=5
order by
o1,o2

原SQL为select c1,c2,c3 from t1,t2,t3 where condi1=5 and condi6=6 or condi7=7 group by g1,g2
解析后的SQL为
select
c1,c2,c3
from
t1,t2,t3
where
condi1=5 and condi6=6 or condi7=7
group by
g1,g2

原SQL为Select c1,c2,c3 From t1,t2,t3 Where condi1=5 and condi6=6 or condi7=7 Group by g1,g2
解析后的SQL为
select
c1,c2,c3
from
t1,t2,t3
where
condi1=5 and condi6=6 or condi7=7
group by
g1,g2

原SQL为Select c1,c2,c3 From t1,t2,t3 Where condi1=5 and condi6=6 or condi7=7 Group by g1,g2,g3 order by g2,g3
解析后的SQL为
select
c1,c2,c3
from
t1,t2,t3
where
condi1=5 and condi6=6 or condi7=7
group by
g1,g2,g3
order by
g2,g3

解析效果之二（isSingleLine=true）：
原SQL为select * from dual
解析后的SQL为
select
*
from
dual

原SQL为SELECT * frOm dual
解析后的SQL为
select
*
from
dual

原SQL为Select C1,c2 From tb
解析后的SQL为
select
C1,
c2
from
tb

原SQL为select c1,c2 from tb
解析后的SQL为
select
c1,
c2
from
tb

原SQL为select count(*) from t1
解析后的SQL为
select
count(*)
from
t1

原SQL为select c1,c2,c3 from t1 where condi1=1
解析后的SQL为
select
c1,
c2,
c3
from
t1
where
condi1=1

原SQL为Select c1,c2,c3 From t1 Where condi1=1
解析后的SQL为
select
c1,
c2,
c3
from
t1
where
condi1=1

原SQL为select c1,c2,c3 from t1,t2 where condi3=3 or condi4=5 order by o1,o2
解析后的SQL为
select
c1,
c2,
c3
from
t1,
t2
where
condi3=3 or
condi4=5
order by
o1,
o2

原SQL为Select c1,c2,c3 from t1,t2 Where condi3=3 or condi4=5 Order by o1,o2
解析后的SQL为
select
c1,
c2,
c3
from
t1,
t2
where
condi3=3 or
condi4=5
order by
o1,
o2

原SQL为select c1,c2,c3 from t1,t2,t3 where condi1=5 and condi6=6 or condi7=7 group by g1,g2
解析后的SQL为
select
c1,
c2,
c3
from
t1,
t2,
t3
where
condi1=5 and
condi6=6 or
condi7=7
group by
g1,
g2

原SQL为Select c1,c2,c3 From t1,t2,t3 Where condi1=5 and condi6=6 or condi7=7 Group by g1,g2
解析后的SQL为
select
c1,
c2,
c3
from
t1,
t2,
t3
where
condi1=5 and
condi6=6 or
condi7=7
group by
g1,
g2

原SQL为Select c1,c2,c3 From t1,t2,t3 Where condi1=5 and condi6=6 or condi7=7 Group by g1,g2,g3 order by g2,g3
解析后的SQL为
select
c1,
c2,
c3
from
t1,
t2,
t3
where
condi1=5 and
condi6=6 or
condi7=7
group by
g1,
g2,
g3
order by
g2,
g3

使用的类SqlParser，你可以拷贝下来使用之：
package com.sitinspring.common.sqlFormatter;

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
* SQL语句解析器类
* @author: sitinspring(junglesong@gmail.com)
* @date: 2008-3-12
*/
public class SqlParser{
/**
* 逗号
*/
private static final String Comma = ",";

/**
* 四个空格
*/
private static final String FourSpace = " ";

/**
* 是否单行显示字段，表，条件的标识量
*/
private static boolean isSingleLine=true;

/**
* 待解析的SQL语句
*/
private String sql;

/**
* SQL中选择的列
*/
private String cols;

/**
* SQL中查找的表
*/
private String tables;

/**
* 查找条件
*/
private String conditions;

/**
* Group By的字段
*/
private String groupCols;

/**
* Order by的字段
*/
private String orderCols;

/**
* 构造函数
* 功能：传入构造函数，解析成字段，表，条件等
* @param sql：传入的SQL语句
*/
public SqlParser(String sql){
this.sql=sql.trim();

parseCols();
parseTables();
parseConditions();
parseGroupCols();
parseOrderCols();
}

/**
* 解析选择的列
*
*/
private void parseCols(){
String regex="(select)(.+)(from)";
cols=getMatchedString(regex,sql);
}

/**
* 解析选择的表
*
*/
private void parseTables(){
String regex="";

if(isContains(sql,"\\s+where\\s+")){
regex="(from)(.+)(where)";
}
else{
regex="(from)(.+)($)";
}

tables=getMatchedString(regex,sql);
}

/**
* 解析查找条件
*
*/
private void parseConditions(){
String regex="";

if(isContains(sql,"\\s+where\\s+")){
// 包括Where，有条件

if(isContains(sql,"group\\s+by")){
// 条件在where和group by之间
regex="(where)(.+)(group\\s+by)";
}
else if(isContains(sql,"order\\s+by")){
// 条件在where和order by之间
regex="(where)(.+)(order\\s+by)";
}
else{
// 条件在where到字符串末尾
regex="(where)(.+)($)";
}
}
else{
// 不包括where则条件无从谈起，返回即可
return;
}

conditions=getMatchedString(regex,sql);
}

/**
* 解析GroupBy的字段
*
*/
private void parseGroupCols(){
String regex="";

if(isContains(sql,"group\\s+by")){
// 包括GroupBy，有分组字段

if(isContains(sql,"order\\s+by")){
// group by 后有order by
regex="(group\\s+by)(.+)(order\\s+by)";
}
else{
// group by 后无order by
regex="(group\\s+by)(.+)($)";
}
}
else{
// 不包括GroupBy则分组字段无从谈起，返回即可
return;
}

groupCols=getMatchedString(regex,sql);
}

/**
* 解析OrderBy的字段
*
*/
private void parseOrderCols(){
String regex="";

if(isContains(sql,"order\\s+by")){
// 包括GroupBy，有分组字段
regex="(order\\s+by)(.+)($)";
}
else{
// 不包括GroupBy则分组字段无从谈起，返回即可
return;
}

orderCols=getMatchedString(regex,sql);
}

/**
* 从文本text中找到regex首次匹配的字符串，不区分大小写
* @param regex： 正则表达式
* @param text：欲查找的字符串
* @return regex首次匹配的字符串，如未匹配返回空
*/
private static String getMatchedString(String regex,String text){
Pattern pattern=Pattern.compile(regex,Pattern.CASE_INSENSITIVE);

Matcher matcher=pattern.matcher(text);

while(matcher.find()){
return matcher.group(2);
}

return null;
}

/**
* 看word是否在lineText中存在，支持正则表达式
* @param lineText
* @param word
* @return
*/
private static boolean isContains(String lineText,String word){
Pattern pattern=Pattern.compile(word,Pattern.CASE_INSENSITIVE);
Matcher matcher=pattern.matcher(lineText);
return matcher.find();
}

public String toString(){
// 无法解析则原样返回
if(cols==null && tables==null && conditions==null && groupCols==null && orderCols==null ){
return sql;
}

StringBuffer sb=new StringBuffer();
sb.append("原SQL为"+sql+"\n");
sb.append("解析后的SQL为\n");

for(String str:getParsedSqlList()){
sb.append(str);
}

sb.append("\n");

return sb.toString();
}

/**
* 在分隔符后加上回车
* @param str
* @param splitStr
* @return
*/
private static String getAddEnterStr(String str,String splitStr){
Pattern p = Pattern.compile(splitStr,Pattern.CASE_INSENSITIVE);

// 用Pattern类的matcher()方法生成一个Matcher对象
Matcher m = p.matcher(str);
StringBuffer sb = new StringBuffer();

// 使用find()方法查找第一个匹配的对象
boolean result = m.find();

// 使用循环找出模式匹配的内容替换之,再将内容加到sb里
while (result) {
m.appendReplacement(sb, m.group(0) + "\n ");
result = m.find();
}
// 最后调用appendTail()方法将最后一次匹配后的剩余字符串加到sb里；
m.appendTail(sb);

return FourSpace+sb.toString();
}

/**
* 取得解析的SQL字符串列表
* @return
*/
public List<String> getParsedSqlList(){
List<String> sqlList=new ArrayList<String>();

// 无法解析则原样返回
if(cols==null && tables==null && conditions==null && groupCols==null && orderCols==null ){
sqlList.add(sql);
return sqlList;
}

if(cols!=null){
sqlList.add("select\n");
if(isSingleLine){
sqlList.add(getAddEnterStr(cols,Comma));
}
else{
sqlList.add(FourSpace+cols);
}
}

if(tables!=null){
sqlList.add(" \nfrom\n");

if(isSingleLine){
sqlList.add(getAddEnterStr(tables,Comma));
}
else{
sqlList.add(FourSpace+tables);
}
}

if(conditions!=null){
sqlList.add(" \nwhere\n");

if(isSingleLine){
sqlList.add(getAddEnterStr(conditions,"(and|or)"));
}
else{
sqlList.add(FourSpace+conditions);
}
}

if(groupCols!=null){
sqlList.add(" \ngroup by\n");

if(isSingleLine){
sqlList.add(getAddEnterStr(groupCols,Comma));
}
else{
sqlList.add(FourSpace+groupCols);
}
}

if(orderCols!=null){
sqlList.add(" \norder by\n");

if(isSingleLine){
sqlList.add(getAddEnterStr(orderCols,Comma));
}
else{
sqlList.add(FourSpace+orderCols);
}
}

return sqlList;
}

/**
* 设置是否单行显示表，字段，条件等
* @param isSingleLine
*/
public static void setSingleLine(boolean isSingleLine) {
SqlParser.isSingleLine = isSingleLine;
}

/**
* 测试
* @param args
*/
public static void main(String[] args){
List<String> ls=new ArrayList<String>();
ls.add("select * from dual");
ls.add("SELECT * frOm dual");
ls.add("Select C1,c2 From tb");
ls.add("select c1,c2 from tb");
ls.add("select count(*) from t1");
ls.add("select c1,c2,c3 from t1 where condi1=1 ");
ls.add("Select c1,c2,c3 From t1 Where condi1=1 ");
ls.add("select c1,c2,c3 from t1,t2 where condi3=3 or condi4=5 order by o1,o2");
ls.add("Select c1,c2,c3 from t1,t2 Where condi3=3 or condi4=5 Order by o1,o2");
ls.add("select c1,c2,c3 from t1,t2,t3 where condi1=5 and condi6=6 or condi7=7 group by g1,g2");
ls.add("Select c1,c2,c3 From t1,t2,t3 Where condi1=5 and condi6=6 or condi7=7 Group by g1,g2");
ls.add("Select c1,c2,c3 From t1,t2,t3 Where condi1=5 and condi6=6 or condi7=7 Group by g1,g2,g3 order by g2,g3");

for(String sql:ls){
System.out.println(new SqlParser(sql));
//System.out.println(sql);
}
}
}