动态SQL拼接处理工具类,为了传动态参数sql语句拼接的灵活使用。具体源代码见：

https://github.com/ticktack/kungfu/blob/master/src/main/java/org/kungfu/sql/DynamicSQL.java

下面简单介绍下使用Demo:

public static void main(String[] args) throws IOException {
	DynamicSQL dsql = new DynamicSQL();
	dsql.append("SELECT s.dept_name, s.id, s.name, t.year, t.semester, t.course_id, t.grade  ");
	dsql.append("  FROM student s   ");
	dsql.append("  LEFT JOIN takes t ON s.id = t.id ");
	dsql.append("  where s.id = '1'      ");
	dsql.isNotEmpty(" and t.year = #    ", "2015");
	dsql.isNotEmpty(" and t.month = #    ", "");
	dsql.isEqual(" and t.semester = $  ", 2, 2);

	System.out.println(dsql.getSql());
	System.out.println(dsql.getParams());
	System.out.println(dsql);
	System.out.println("+++++++++++++++++++++++++++++++++++++++++++");
	dsql.clear();

	dsql.append("SELECT s.dept_name, s.id, s.name, t.year, t.semester, t.course_id, t.grade  ");
	dsql.append("  FROM student s   ");
	dsql.append("  LEFT JOIN takes t ON s.id = t.id ");
	dsql.append("  where s.id = '1'      ");
	dsql.isNotEmpty(" and t.year = #    ", "2015");
	dsql.isNotEmpty(" and t.month = $    ", "");
	dsql.isEqual(" and t.semester = $  ", new Integer(3), new Integer(3));
	dsql.isEqual(" and t.semester2 = $  ", 5, 5);

	System.out.println(dsql.getSql());
	System.out.println(dsql.getParams());
	System.out.println(dsql);
	System.out.println("+++++++++++++++++++++++++++++++++++++++++++");
	dsql.clear();


	String ids = "1, 2, 3, 4, 5";
	//dsql.append("delete from sdt_bdi_std_type ");
	//dsql.isNotEmpty("  where id in ($) ", ids);
	dsql.isNotEmpty(String.format("delete from %s where id in ($) ", "sdt_bdi_std_type"), ids);
	System.out.println(dsql.getSql());
	System.out.println(dsql.getParams());
	System.out.println(dsql);
}

运行的结果如下：

SELECT s.dept_name, s.id, s.name, t.year, t.semester, t.course_id, t.grade FROM student s LEFT JOIN takes t ON s.id = t.id where s.id = '1' and t.year = ? and t.semester = ? 

[2015, 2]

SELECT s.dept_name, s.id, s.name, t.year, t.semester, t.course_id, t.grade FROM student s LEFT JOIN takes t ON s.id = t.id where s.id = '1' and t.year = '2015' and t.semester =  2  

+++++++++++++++++++++++++++++++++++++++++++

SELECT s.dept_name, s.id, s.name, t.year, t.semester, t.course_id, t.grade FROM student s LEFT JOIN takes t ON s.id = t.id where s.id = '1' and t.year = ? and t.semester2 = ? 

[2015, 5]

SELECT s.dept_name, s.id, s.name, t.year, t.semester, t.course_id, t.grade FROM student s LEFT JOIN takes t ON s.id = t.id where s.id = '1' and t.year = '2015' and t.semester2 =  5  

+++++++++++++++++++++++++++++++++++++++++++

delete from sdt_bdi_std_type where id in (?) 

[1, 2, 3, 4, 5]

delete from sdt_bdi_std_type where id in ( 1, 2, 3, 4, 5 )