我试图通过Prepared Statement使用相同的连接执行多个查询但是无法完全实现它！
代码段：
public class PostPrReqDaoImpl implements PostPrReqDaoInterface {
@Override
public boolean validate(PostPrReqBean pprb1,PostPrReqBean pprb2,PostPrReqBean pprb3) {
System.out.println("Inside PostPrReq Dao");
int resstat=1;
//snuname,snuusrname,snupass,snuempid,snuemail,snudob,snuskill,snuexp,snudesg;
java.io.PrintWriter out = null;
try {
out = pprb1.getBeanresponse().getWriter();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
pprb1.getBeanresponse().setContentType("text/html");
Connection conn=null;
try {
/* get the DataSource from using the JNDI name */
Class.forName("com.mysql.jdbc.Driver");
InitialContext ctx = new InitialContext();
DataSource ds = (DataSource)ctx.lookup("java:comp/env/jdbc/Test");
//username, pass,name, id,dob ,skillset, exp,designation ,email
//Create connection and then continue as usual other JDBC calls
conn=ds.getConnection();
System.out.println("Connection succesful!");
if(resstat == 1)
{
System.out.println();
String sqlproj1 = "INSERT INTO tblproject (name,code,location,type,lastdate)"
+ " VALUES (?,?,?,?,?)";
//Create a PreparedStatment with that sql and insert the values with index:
PreparedStatement preparedStatement1a = conn.prepareStatement(sqlproj1);
preparedStatement1a.setString(1,pprb1.getBeanprojname());
preparedStatement1a.setString(2,pprb1.getBeanprojcode());
preparedStatement1a.setString(3,pprb1.getBeanprojlocation());
preparedStatement1a.setString(4,pprb1.getBeanprojtype());
preparedStatement1a.setString(5,pprb1.getBeanprojlastdate());
preparedStatement1a.executeUpdate();
preparedStatement1a.clearParameters();
String sqlreq1="INSERT INTO tblrequirements (code,designation,skillset,exp,ncand)"
+ " VALUES (?,?,?,?,?)";
//Create a PreparedStatment with that sql and insert the values with index:
PreparedStatement preparedStatement1b = conn.prepareStatement(sqlreq1);
preparedStatement1b.setString(1,pprb1.getBeanprojcode());
preparedStatement1b.setString(2,pprb1.getBeandesg());
preparedStatement1b.setString(3,pprb1.getBeanskill());
preparedStatement1b.setInt(4,pprb1.getBeanexp());
preparedStatement1b.setInt(5,pprb1.getBeanncand());
preparedStatement1a.executeUpdate();
preparedStatement1b.executeUpdate();
System.out.println("Data 1 inserted successfully!");
String sqlproj2 = "INSERT INTO tblproject (name,code,location,type,lastdate)"
+ " VALUES (?,?,?,?,?)";
//Create a PreparedStatment with that sql and insert the values with index:
PreparedStatement preparedStatement2a = conn.prepareStatement(sqlproj2);
preparedStatement2a.setString(1,pprb2.getBeanprojname());
preparedStatement2a.setString(2,pprb2.getBeanprojcode());
preparedStatement2a.setString(3,pprb2.getBeanprojlocation());
preparedStatement2a.setString(4,pprb2.getBeanprojtype());
preparedStatement2a.setString(5,pprb2.getBeanprojlastdate());
String sqlreq2="INSERT INTO tblrequirements (code,designation,skillset,exp,ncand)"
+ " VALUES (?,?,?,?,?)";
//Create a PreparedStatment with that sql and insert the values with index:
PreparedStatement preparedStatement2b = conn.prepareStatement(sqlreq2);
preparedStatement2b.setString(1,pprb2.getBeanprojcode());
preparedStatement2b.setString(2,pprb2.getBeandesg());
preparedStatement2b.setString(3,pprb2.getBeanskill());
preparedStatement2b.setInt(4,pprb2.getBeanexp());
preparedStatement2b.setInt(5,pprb2.getBeanncand());
preparedStatement2a.executeUpdate();
preparedStatement2b.executeUpdate();
System.out.println("Data 2 inserted successfully!");
String sqlproj3= "INSERT INTO tblproject (name,code,location,type,lastdate)"
+ " VALUES (?,?,?,?,?)";
//Create a PreparedStatment with that sql and insert the values with index:
PreparedStatement preparedStatement3a = conn.prepareStatement(sqlproj3);
preparedStatement3a.setString(1,pprb3.getBeanprojname());
preparedStatement3a.setString(2,pprb3.getBeanprojcode());
preparedStatement3a.setString(3,pprb3.getBeanprojlocation());
preparedStatement3a.setString(4,pprb3.getBeanprojtype());
preparedStatement3a.setString(5,pprb3.getBeanprojlastdate());
String sqlreq3="INSERT INTO tblrequirements (code,designation,skillset,exp,ncand)"
+ " VALUES (?,?,?,?,?)";
//Create a PreparedStatment with that sql and insert the values with index:
PreparedStatement preparedStatement3b = conn.prepareStatement(sqlreq3);
preparedStatement3b.setString(1,pprb3.getBeanprojcode());
preparedStatement3b.setString(2,pprb3.getBeandesg());
preparedStatement3b.setString(3,pprb3.getBeanskill());
preparedStatement3b.setInt(4,pprb3.getBeanexp());
preparedStatement3b.setInt(5,pprb3.getBeanncand());
preparedStatement3a.executeUpdate();
preparedStatement3b.executeUpdate();
System.out.println("Data 3 inserted successfully!");
preparedStatement1a.clearParameters();
preparedStatement1b.clearParameters();
preparedStatement2a.clearParameters();
preparedStatement2b.clearParameters();
preparedStatement3a.clearParameters();
preparedStatement3b.clearParameters();
}
} catch (Exception e){
out.println("Failed!"+ e);
resstat=0;
}
if(resstat==1)
return true;
else
return false;
}
}
它正在执行前两个查询，但不是从第3个开始执行。
答案 0 :(得分：3)
我在这里看到一个潜在的问题：
...
preparedStatement1a.executeUpdate();
preparedStatement1a.clearParameters(); // you clear the parameters of
// preparedStatement1a
...
preparedStatement1a.executeUpdate(); // then you try to execute it
// again without parameters
preparedStatement1b.executeUpdate();