首页 > 编程学习 > Spring框架JDBC Template使用教程

Spring框架JDBC Template使用教程

发布时间:2022/12/10 17:55:19

前言

Spring提供了一个JDBCTemplate对象简化JDBC的开发,本文将简单讲解一下Spring框架JDBC Template使用教程以及Spring框架对JDBC的简单封装。

步骤

1.导入jar包

2.创建JdbcTemplate对象。依赖于数据源DataSource

  • JdbcTemplate template = new JdbcTemplate(ds);

3.调用JdbcTemplate的方法来完成CRUD的操作

  • update():执行DML语句。增、删、改语句
  • queryForMap():查询结果将结果集封装为map集合,将列名作为key,将值作为value 将这条记录封装为一个map集合
    * 注意:这个方法查询的结果集长度只能是1
  • queryForList():查询结果将结果集封装为list集合
    * 注意:将每一条记录封装为一个Map集合,再将Map集合装载到List集合中
  • query():查询结果,将结果封装为JavaBean对象
    • query的参数:RowMapper
      * 一般我们使用BeanPropertyRowMapper实现类。可以完成数据到JavaBean的自动封装
      * new BeanPropertyRowMapper<类型>(类型.class)
  • queryForObject:查询结果,将结果封装为对象
    * 一般用于聚合函数的查询

练习:

需求:

  1. 修改1号数据的 salary 为 10000
  2. 添加一条记录
  3. 删除刚才添加的记录
  4. 查询id为1的记录,将其封装为Map集合
  5. 查询所有记录,将其封装为List
  6. 查询所有记录,将其封装为Emp对象的List集合
  7. 查询总记录数

实体类Emp:

import java.util.Date;public class Emp {private Integer id;private String ename;private Integer job_id;private Integer mgr;private Date joindate;private Double salary;private Double bonus;private Integer dept_id;public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getEname() {return ename;}public void setEname(String ename) {this.ename = ename;}public Integer getJob_id() {return job_id;}public void setJob_id(Integer job_id) {this.job_id = job_id;}public Integer getMgr() {return mgr;}public void setMgr(Integer mgr) {this.mgr = mgr;}public Date getJoindate() {return joindate;}public void setJoindate(Date joindate) {this.joindate = joindate;}public Double getSalary() {return salary;}public void setSalary(Double salary) {this.salary = salary;}public Double getBonus() {return bonus;}public void setBonus(Double bonus) {this.bonus = bonus;}public Integer getDept_id() {return dept_id;}public void setDept_id(Integer dept_id) {this.dept_id = dept_id;}@Overridepublic String toString() {return "Emp{" +"id=" + id +", ename='" + ename + '\'' +", job_id=" + job_id +", mgr=" + mgr +", joindate=" + joindate +", salary=" + salary +", bonus=" + bonus +", dept_id=" + dept_id +'}';}
}

Druid连接池的工具类

import com.alibaba.druid.pool.DruidDataSourceFactory;import javax.sql.DataSource;
import java.io.IOException;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;/*** Druid连接池的工具类*/
public class JDBCUtils {//1.定义成员变量 DataSourceprivate static DataSource ds ;static{try {//1.加载配置文件Properties pro = new Properties();pro.load(JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties"));//2.获取DataSourceds = DruidDataSourceFactory.createDataSource(pro);} catch (IOException e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();}}/*** 获取连接*/public static Connection getConnection() throws SQLException {return ds.getConnection();}/*** 释放资源*/public static void close(Statement stmt,Connection conn){/* if(stmt != null){try {stmt.close();} catch (SQLException e) {e.printStackTrace();}}if(conn != null){try {conn.close();//归还连接} catch (SQLException e) {e.printStackTrace();}}*/close(null,stmt,conn);}public static void close(ResultSet rs , Statement stmt, Connection conn){if(rs != null){try {rs.close();} catch (SQLException e) {e.printStackTrace();}}if(stmt != null){try {stmt.close();} catch (SQLException e) {e.printStackTrace();}}if(conn != null){try {conn.close();//归还连接} catch (SQLException e) {e.printStackTrace();}}}/*** 获取连接池方法*/public static DataSource getDataSource(){return  ds;}}

增删改查:

import cn.itcast.domain.Emp;
import cn.itcast.utils.JDBCUtils;
import org.junit.Test;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;import java.sql.Date;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import java.util.Map;public class JdbcTemplateDemo2 {//Junit单元测试,可以让方法独立执行//1. 获取JDBCTemplate对象private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());/*** 1. 修改1号数据的 salary 为 10000*/@Testpublic void test1(){//2. 定义sqlString sql = "update emp set salary = 10000 where id = 1001";//3. 执行sqlint count = template.update(sql);System.out.println(count);}/*** 2. 添加一条记录*/@Testpublic void test2(){String sql = "insert into emp(id,ename,dept_id) values(?,?,?)";int count = template.update(sql, 1015, "郭靖", 10);System.out.println(count);}/*** 3.删除刚才添加的记录*/@Testpublic void test3(){String sql = "delete from emp where id = ?";int count = template.update(sql, 1015);System.out.println(count);}/*** 4.查询id为1001的记录,将其封装为Map集合* 注意:这个方法查询的结果集长度只能是1*/@Testpublic void test4(){String sql = "select * from emp where id = ? or id = ?";Map<String, Object> map = template.queryForMap(sql, 1001,1002);System.out.println(map);//{id=1001, ename=孙悟空, job_id=4, mgr=1004, joindate=2000-12-17, salary=10000.00, bonus=null, dept_id=20}}/*** 5. 查询所有记录,将其封装为List*/@Testpublic void test5(){String sql = "select * from emp";List<Map<String, Object>> list = template.queryForList(sql);for (Map<String, Object> stringObjectMap : list) {System.out.println(stringObjectMap);}}/*** 6. 查询所有记录,将其封装为Emp对象的List集合*/@Testpublic void test6(){String sql = "select * from emp";List<Emp> list = template.query(sql, new RowMapper<Emp>() {@Overridepublic Emp mapRow(ResultSet rs, int i) throws SQLException {Emp emp = new Emp();int id = rs.getInt("id");String ename = rs.getString("ename");int job_id = rs.getInt("job_id");int mgr = rs.getInt("mgr");Date joindate = rs.getDate("joindate");double salary = rs.getDouble("salary");double bonus = rs.getDouble("bonus");int dept_id = rs.getInt("dept_id");emp.setId(id);emp.setEname(ename);emp.setJob_id(job_id);emp.setMgr(mgr);emp.setJoindate(joindate);emp.setSalary(salary);emp.setBonus(bonus);emp.setDept_id(dept_id);return emp;}});for (Emp emp : list) {System.out.println(emp);}}/*** 6. 查询所有记录,将其封装为Emp对象的List集合*/@Testpublic void test6_2(){String sql = "select * from emp";List<Emp> list = template.query(sql, new BeanPropertyRowMapper<Emp>(Emp.class));for (Emp emp : list) {System.out.println(emp);}}/*** 7. 查询总记录数*/@Testpublic void test7(){String sql = "select count(id) from emp";Long total = template.queryForObject(sql, Long.class);System.out.println(total);}}

本文链接:https://www.ngui.cc/el/2314910.html
Copyright © 2010-2022 ngui.cc 版权所有 |关于我们| 联系方式| 豫B2-20100000