菜鸟第一发：jdbc多条件组合查询

1 <form action="" method="post">
2   编号:<input type="text" name="field1" size="30"/>
3   修改日期:<input type="text" name="field2" size="30">
4   <input type="submit">
5 </form>

 1 String field1=request.getParameter("field1");                                             String field2=request.getParameter("field2");                              
 2 Map<String, Object>map=new HashMap<String,Object>();     //用HashMap以键值对的形式存储数据库字段名和赋值
 3 if(field1!=null&&!field1.equals("")){
 4                 map.put("field1", field1);               
 5             }
 6 if(field2!=null&&!field2.equals("")){
 7                 map.put("field2", field2);
 8             }
 9 StringBuffer sqlBuffer=new StringBuffer("select * from tableName where 1=1");
10 for(final Entry<String, Object> entry:map.entrySet()){
11                     sqlBuffer.append(" and ").append(entry.getKey()).append("=?");        //字符串流动态拼接sql语句
12                 }
13                 System.out.println(sqlBuffer.toString());
14                 pstmt=con.prepareStatement(sqlBuffer.toString(),ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
15                 int i=1;
16                 for(final Entry<String, Object> entry:map.entrySet()){
17                     pstmt.setObject(i, entry.getValue());                                          //动态为占位符赋值
18                     i++;
19                 }
20 pstmt.execute();
21 ResultSet rSet=pstmt.getResultSet;
22