java - org.apache.commons.dbcp.DelegatingPreparedStatement 无法转换为 com.mysql.jdbc.PreparedStatement

Question

我正在尝试使用准备好的语句查询数据库，但是出现错误:org.apache.commons.dbcp.DelegatingPreparedStatement 无法转换为 com.mysql.jdbc.PreparedStatement。

导入

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.PreparedStatementCreator;
import org.springframework.jdbc.core.ResultSetExtractor;
import org.springframework.jdbc.core.simple.ParameterizedRowMapper;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
import org.springframework.jdbc.support.GeneratedKeyHolder;
import org.springframework.jdbc.support.KeyHolder;
import org.springframework.stereotype.Repository;


import com.mysql.jdbc.PreparedStatement;
import com.mysql.jdbc.Statement;

JDBC

public List<Crime> getCrimeList(Crime crime) {
        String where_clause = "";

        final List<Object> args = new ArrayList<Object>();
        final StringBuilder whereClause = new StringBuilder();


        if (crime.getCrimeDate()!= null){
             whereClause.append(" and crime.crimeDate = ?");
             args.add(crime.getCrimeDate());

        }

        if(crime.getCrimeDetails() != null){
            whereClause.append(" and crime.crimeDetails = ?");
             args.add(crime.getCrimeDetails());

        }

        ..............

        logger.debug("In getCrimeList()");
        final String sql = "select crime.*, "+
                     "criminalSocialSecurityNumber,criminal.fName as criminalFName,criminal.lName as criminalLName,"+
                     "criminal.photo as criminalPhoto,criminal.dob as criminalDob,victimSocialSecurityNumber,"+
                     "victim.fName as victimFName,victim.lName as victimLName,victim.photo as victimPhoto, victim.dob as victimDob "+ 
                     "from tblcrimes crime "+
                     "left join tblcriminalcrime on crime.crimeRecNo = tblcriminalcrime.crimeRecNo "+
                     "left join tblvictimcrime on crime.crimeRecNo = tblvictimcrime.crimeRecNo "+
                     "inner join tblcitizens criminal on criminal.socialSecurityNumber = tblcriminalcrime.criminalSocialSecurityNumber "+
                     "inner join tblcitizens victim on victim.socialSecurityNumber = tblvictimcrime.victimSocialSecurityNumber ";

        logger.debug("Executing getCrimeList String "+sql);



        List<Crime> crimeList = getJdbcTemplate().query(new PreparedStatementCreator(){

        public java.sql.PreparedStatement createPreparedStatement(
                java.sql.Connection connection) throws SQLException {

            PreparedStatement ps =(PreparedStatement) connection.prepareStatement(sql + whereClause);
            int i = 1;
            for (Object arg : args) {
                ps.setObject(i, arg);
                i++;
            }

            return ps;
        }
        },  new CrimeMapper());      



        return crimeList;   

    }

错误

HTTP Status 500 - Request processing failed; nested exception is java.lang.ClassCastException: org.apache.commons.dbcp.DelegatingPreparedStatement cannot be cast to com.mysql.jdbc.PreparedStatement

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.ClassCastException: org.apache.commons.dbcp.DelegatingPreparedStatement cannot be cast to com.mysql.jdbc.PreparedStatement

org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:894)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)

root cause

java.lang.ClassCastException: org.apache.commons.dbcp.DelegatingPreparedStatement cannot be cast to com.mysql.jdbc.PreparedStatement
    com.crimetrack.jdbc.JdbcCrimeDAO$2.createPreparedStatement(JdbcCrimeDAO.java:372)
    org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:581)
    org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:637)
    org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:662)
    com.crimetrack.jdbc.JdbcCrimeDAO.getCrimeList(JdbcCrimeDAO.java:367)
    com.crimetrack.service.CrimeManager.getCrimesList(CrimeManager.java:24)
    com.crimetrack.web.CrimeRegistrationController.handelCrimeList(CrimeRegistrationController.java:229)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    java.lang.reflect.Method.invoke(Unknown Source)
    org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:213)
    org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
    org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617)
    org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
    org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
    org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:728)

Answer 1

上线:

PreparedStatement ps =(PreparedStatement) connection.prepareStatement(sql + whereClause);

您确定 PreparedStatement 是 java.sql.PreparedStatement 吗？

不确定为什么需要转换从 connection.prepareStatement() 返回的对象。此方法返回 java.sql.PreparedStatement 类型的对象。请检查您的导入语句是否正确导入了类。