Statement stat = conn.createStatement(); 或者 preparedstatement
或者dbutil辅助类,接收不同类型的数据库查询结果
4.执行sql
5.处理结果
6.回收资源
jdbctample
spring中提供了 jdbctample辅助查询,不用再管连接池 回收资源 之类的
1.需要在xml中声明 jdbctample,并提供数据源
2.调用时,@autowired声明 jdbctample
package com.hxut.rj92.zyk.dao;
import com.hxut.rj92.zyk.Student;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Component;
import javax.sql.DataSource;
import java.util.Arrays;
import java.util.List;
@Component
public class UserdaoImpl implements Userdao{
@Autowired
JdbcTemplate jdbcTemplate;
@Override
public int add_dao(Student student) {
int a= jdbcTemplate.update(" insert student values(?,?,?);", new Object[]{student.getName(), (Integer)student.getId(), student.getLoc()});
return a;
}
@Override
public int change_dao(Student student) {
int a= jdbcTemplate.update(" update student set name=?,loc=? where id=?;", new Object[]{student.getName(),student.getLoc(),(Integer)student.getId() });
return a;
}
public int del_dao(int id)
{
int a =jdbcTemplate.update("delete from student where id =?",new Object [] {id});
return a;
}
public int select_counts_dao()//查询行数
{
int a=jdbcTemplate.queryForObject("select count(*) from student",Integer.class);//第二个参数表示返回类型的class,因为是int类型,所以就是intenger
return a;
}
public Student select_one_info_dao(int id)//查询一行数据的详细信息
{ //注意student类中要有无参的构造函数
String sql="select * from student where id=?";
//第一个参数是sql语句,第二个是返回值类型(固定写法),第三个是sql参数的值
Student student=jdbcTemplate.queryForObject(sql,new BeanPropertyRowMapper(Student.class),id);
return student;
}
public List select_all_list_dao()
{//和查询一个相比,使用的是query方法,参数没变
String sql="select * from student where id<=?";
List students=jdbcTemplate.query(sql,new BeanPropertyRowMapper(Student.class),99);
return students;
}
//批量插入,一下插入好几行数据
public void add_batch_dao(List