Spring与JDBC整合应用

Posted 2020-10-02

Spring与JDBC整合背景：

1.Spring提供了编写Dao的工具类：JdbcTemplate

　　　　JdbcTemplate.update("insert....",参数);

　　　　JdbcTemplate.query();//查询多行记录

               JdbcTemplate.queryForObject();//查询单行记录

               int rows=JdbcTemplate.queryForInt();

2.Spring提供了AOP式事务管理（不需要在方法中追加事务提交和回滚）

3.提供了统一的异常处理：DataAccessException

 

Spring整合JDBC步骤:

A.搭建开发环境：引入Spring(ioc,aop,dao)开发包，添加applicationContext.xml文件

　　　　　　　　配置数据驱动及dbcp连接池

B.编写实体类及

package com.web.entity;
import java.io.Serializable;
public class Emp implements Serializable {
    //封装类可以分装null值
    private Integer id;
    private String name;
    private Double salary;
    private Integer age;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Double getSalary() {
        return salary;
    }
    public void setSalary(Double salary) {
        this.salary = salary;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
}

注意：当需要查询时必须创建该表对应的RowMapper类（将记录映射成对象）如下：

package com.web.entity;

import java.sql.ResultSet;
import java.sql.SQLException;

import org.springframework.jdbc.core.RowMapper;
/*
 * 将emp记录封装为Emp对象
 */

public class EmpRowMapper implements RowMapper<Emp>{

    public Emp mapRow(ResultSet rs, int index) throws SQLException {
        //将当前rs指针指向的记录取出，封装成Emp返回
        Emp emp=new Emp();
        emp.setId(rs.getInt("id"));
        emp.setName(rs.getString("name"));
        emp.setSalary(rs.getDouble("salary"));
        emp.setAge(rs.getInt("age"));
        return emp;
    }
}

 

C.编写DAO组件：实现增删改查

package com.web.dao;

import java.util.List;

import javax.annotation.Resource;

import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

import com.web.entity.Emp;
import com.web.entity.EmpRowMapper;

@Repository //扫描Dao
public class EmpDao {
    @Resource//注入
    private JdbcTemplate template;//注入，另一种方法是继承
    public void save(Emp emp){
        String sql="insert into emp (name,salary,age) values(?,?,?)";
        Object[] params={emp.getName(),
                         emp.getSalary(),
                         emp.getAge()
                         };
        template.update(sql,params);
    }
    
    public void delete(int id){
        String sql="delete from emp where id=?";
        Object[] params={id};
        template.update(sql,params);
    }

    public List<Emp> finalAll(){
        String sql="select * from emp";
        EmpRowMapper rowMapper=new EmpRowMapper();
        List<Emp> list=template.query(sql, rowMapper);//rowMapper
        return list;
    }
    //多行查询用query()方法
    //单行查询用queryForObject()方法
    
    public Emp findById(int id){
        String sql="select * from emp where id=?";
        Object[] params={id};
        EmpRowMapper rowMapper=new EmpRowMapper();
        Emp emp=template.queryForObject(sql, params,rowMapper);
        return emp;
    }
    
    
}

 

D.在applicationContext.xml中扫描EmpDao,注入JdbcTemplate

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jpa="http://www.springframework.org/schema/data/jpa" xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:tx="http://www.springframework.org/schema/tx" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
    http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
    http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
    http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.0.xsd">

<!-- 开启组件扫描 -->
<context:component-scan base-package="com.web"/>

<!-- 定义JDBCTemplate -->
<bean id="template" class="org.springframework.jdbc.core.JdbcTemplate">
    <!-- 注入连接信息 -->
    <!-- DataSource:数据源，连接池 -->
    <property name="dataSource" ref="dbcp"></property>
</bean>
    <bean id="dbcp" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="username" value="root"></property>
        <property name="password" value="1234"></property>
        <property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql:///jsd1507db?useUnicode=true&amp;characterEncoding=utf8"></property>
    </bean>
</beans>