spring JdbcTemplate

 

主要类：JdbcTemplate、BeanPropertyRowMapper

　　spring提供了对原始Jdbc API的简单封装：

　　（1）操作关系型数据库

　　　　JdbcTemplate、HibernateTemplate

　　（2）操作nosql数据库

　　　　RedisTemplate

　　（3）操作消息队列

　　　　JmsTemplate

　　需要 spring-jdbc-version.jar 和 spring-tx-version.jar(事务相关) 

<dependency>
    <groupId>org.springframeworkgroupId>
    <artifactId>spring-jdbcartifactId>
    <version>5.2.6.RELEASEversion>
dependency>

<dependency>
    <groupId>org.springframeworkgroupId>
    <artifactId>spring-txartifactId>
    <version>5.2.6.RELEASEversion>
dependency>

 

 

例子：

package com.database.jdbctemplate;

import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DriverManagerDataSource;

import java.util.List;
import java.util.Map;

public class JdbcTemplateDemo {
    public static void main(String[] args) {
        //1.准备数据源(c3p0、druid、DriverManagerDataSource)
        DriverManagerDataSource ds = new DriverManagerDataSource();
        ds.setDriverClassName("com.mysql.cj.jdbc.Driver");
        ds.setUrl("jdbc:mysql://127.0.0.1:3306/testx?serverTimezone=UTC&useUnicode=true&characterEncoding=utf8");
        ds.setUsername("root");
        ds.setPassword("xxx");
        //2.创建JdbcTemplate对象
        JdbcTemplate jt = new JdbcTemplate(ds);
        //3.执行操作
        List> list = jt.queryForList("select * from person");
        for(int i=0;i) {
            Map map = list.get(i);
            for(String key:map.keySet()) {
                System.out.print(key+"  ");
            }
            System.out.println();
        }
        for(int i=0;i) {
            Map map = list.get(i);
            for(String key:map.keySet()) {
                System.out.print(map.get(key)+"  ");
            }
            System.out.println();
        }
    }
}

 

　　可将Driver、url、userName、password放在配置文件里，然后读入：

driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://127.0.0.1:3306/contacts?serverTimezone=UTC&useUnicode=true&characterEncoding=utf8
username=root
password=xxx

　　

try {
    Properties pro = new Properties();

    ClassLoader classLoader = JdbcUtils.class.getClassLoader();
    URL proUrl = classLoader.getResource("jdbc.properties");
    String proPath = proUrl.getPath();

    pro.load(new FileReader(proPath));
    driver = pro.getProperty("driver");
    url = pro.getProperty("url");
    user = pro.getProperty("user");
    password = pro.getProperty("password");
    
}catch(FileNotFoundException e) {
    e.printStackTrace();
}catch(IOException e) {
    e.printStackTrace();
}

 

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改：将JdbcTemplate交给IOC容器创建

　　beanJdbc.xml

xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource1">property>
    bean>

    
    <bean id="dataSource1" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://127.0.0.1:3306/testx?serverTimezone=UTC&useUnicode=true&characterEncoding=utf8"/>    
        <property name="username" value="root"/>
        <property name="password" value="xxx"/>
    bean>
beans>

　　主方法：

//1.获取容器
ApplicationContext ac = new ClassPathXmlApplicationContext("beanJdbc.xml");
//2.获取jdbcTemplate
JdbcTemplate jt = ac.getBean("jdbcTemplate",JdbcTemplate.class);
//3.执行操作
//3.执行操作
List> list = jt.queryForList("select * from person");

 

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查询返回list：

（1）返回 List>

List> list = jt.queryForList("select * from person");

（2）定义实体类，返回实体类的List，自定义结果到实体的映射

package com.database.domain;

/*
* 数据库中表的实体类
* */

import java.io.Serializable;

public class Person implements Serializable {
    private String id;
    private String firstName;
    private String lastName;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
}

　　实体类--结果映射类：

class PersonRowMapper implements RowMapper {

    @Override
    public Person mapRow(ResultSet resultSet, int i) throws SQLException {
        Person p = new Person();
        p.setId(resultSet.getString("PersonId"));
        p.setFirstName(resultSet.getString("FirstName"));
        p.setLastName(resultSet.getString("LastName"));
        return p;
    }
}

　　调用：

List list2 = jt.query("select * from person where PersonId > ?", new PersonRowMapper(), 1);

 

（3）定义实体类，返回实体类的List，使用spring框架的结果--实体映射

　　实体类同上；spring提供了  org.springframework.jdbc.core.BeanPropertyRowMapper

List list3 = jt.query("select * from person where PersonId > ?", new BeanPropertyRowMapper(Person.class), 1);

 

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