摘要:这两天学了Spring中的JdbcTemplate和NamedParameterJdbcTemplate。
一、JdbcTemplate
1、常用方法
- execute方法:可以用于执行任何SQL语句,一般用于执行DDL语句;
- update方法及batchUpdate方法:update方法用于执行新增、修改、删除等语句;batchUpdate方法用于执行批处理相关语句;
- query方法及queryForXXX方法:用于执行查询相关语句;
- call方法:用于执行存储过程、函数相关语句。
2、实例
①在数据库建表
②新建实体类
package com.jdbc; public class Person { private int id; private String name; private String password; private School school; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public School getSchool() { return school; } public void setSchool(School school) { this.school = school; } @Override public String toString() { return "Person [id=" + id + ", name=" + name + ", password=" + password + ", school=" + school + "]"; } }
package com.jdbc; public class School { private int id; private String school; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getSchool() { return school; } public void setSchool(String school) { this.school = school; } @Override public String toString() { return "School [id=" + id + ", school=" + school + "]"; } }
③配置xml文件
<?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:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd"> <!-- 导入资源文件 --> <context:property-placeholder location="classpath:db" /> <context:component-scan base-package="com.jdbc"></context:component-scan> <!-- 配置C3P0数据源 --> <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"> <property name="user" value="${jdbc.user}"></property> <property name="password" value="${jdbc.password}"></property> <property name="driverClass" value="${jdbc.driverClass}"></property> <property name="jdbcUrl" value="${jdbc.jdbcurl}"></property> <property name="initialPoolSize" value="${jdbc.initPoolSize}"></property> <property name="maxPoolSize" value="${jdbc.maxPoolSize}"></property> </bean> <!-- 配置spring的 JdbcTemplate --> <bean id="JdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate"> <property name="dataSource" ref="dataSource"></property> </bean> </beans>
④新建JUnit测试用例类JDBCTest.java并编写测试代码
package com.jdbc; import java.sql.SQLException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import javax.sql.DataSource; import org.junit.jupiter.api.Test; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import org.springframework.jdbc.core.BeanPropertyRowMapper; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.jdbc.core.RowMapper; import org.springframework.jdbc.core.namedparam.BeanPropertySqlParameterSource; import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate; import org.springframework.jdbc.core.namedparam.SqlParameterSource; class JDBCTest { private ApplicationContext c = null; private JdbcTemplate jdbcTemplate; private Dao dao; { c = new ClassPathXmlApplicationContext("jdbc.xml"); jdbcTemplate = (JdbcTemplate) c.getBean("JdbcTemplate"); dao = c.getBean(Dao.class); } @Test public void dao() { System.out.println(dao.get(58)); } /* * 获取单个列的值,或统计查询 */ @Test public void huoqu1() { String sql ="select count(id) from m1"; long count =jdbcTemplate.queryForObject(sql, long.class); System.out.println(count); } /* * 查到实体类集合,不调用queryforlist */ @Test public void list() { String sql="select id, name, password from m1 where id > ?"; RowMapper<Person> rowMapper=new BeanPropertyRowMapper<>(Person.class); List<Person> persons=jdbcTemplate.query(sql, rowMapper,59); System.out.println(persons); } /* *从数据库中获取一条记录,实际得到对应的一个对象 注意不是调用 queryForObject(String sql,Class<Employee> requiredType,Object...args)方法! 而需要调用queryForObject(String sql,RowMapper<Employee> rowMapper,Object...args) 1.其中的 RowMapper 指定如何去映射结果集的行,常用的实现类为 BeanPropertyRowMapper 2.使用 SQL 中列的别名完成列名和类的属性名的映射.例如last_name lastName */ @Test public void huoqu() { String sql="select id, name, password from m1 where id = ?"; RowMapper<Person> rowMapper=new BeanPropertyRowMapper<>(Person.class); Person person = jdbcTemplate.queryForObject(sql, rowMapper,56); System.out.println(person); } /* * 批量更新 */ @Test public void batchUpdateTest() { String sql="insert into m1(name,password) values(?,?)"; List<Object[]> batchArgs = new ArrayList<>(); batchArgs.add(new Object[] {"A","123"}); batchArgs.add(new Object[] {"B","123"}); batchArgs.add(new Object[] {"C","123"}); jdbcTemplate.batchUpdate(sql,batchArgs); } /* * 执行insert,update, delete */ @Test public void updateTest() { String sql="update m1 set name= ? where id = ?"; jdbcTemplate.update(sql, "mmm",1); } @Test public void testDataSource() throws SQLException { DataSource dataSource=c.getBean(DataSource.class); System.out.println(dataSource.getConnection()); } }
package com.jdbc; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.jdbc.core.BeanPropertyRowMapper; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.jdbc.core.RowMapper; import org.springframework.stereotype.Repository; @Repository public class Dao { @Autowired private JdbcTemplate jdbcTemplate; public Person get(int id) { String sql="select id, name, password from m1 where id = ?"; RowMapper<Person> rowMapper=new BeanPropertyRowMapper<>(Person.class); Person persons=jdbcTemplate.queryForObject(sql, rowMapper,id); return persons; } }
二、NamedParameterJdbcTemplate
1、简介
NamedParameterJdbcTemplate类是基于JdbcTemplate类,并对它进行了封装从而支持命名参数特性。
NamedParameterJdbcTemplate主要提供以下三类方法:execute方法、query及queryForXXX方法、update及batchUpdate方法。
2、实例
①基于实例一,在xml文件中新加配置
<!-- 配置NamedParameterJdbcTemplate,可以使用具名参数,没有无参数的构造器 --> <bean id="namedParameterJdbcTemplate" class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate"> <constructor-arg ref="dataSource"></constructor-arg> </bean>
②在JDBCTest.java中新加测试方法
package com.jdbc; import java.sql.SQLException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import javax.sql.DataSource; import org.junit.jupiter.api.Test; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import org.springframework.jdbc.core.BeanPropertyRowMapper; import org.springframework.jdbc.core.JdbcTemplate; import org.springframework.jdbc.core.RowMapper; import org.springframework.jdbc.core.namedparam.BeanPropertySqlParameterSource; import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate; import org.springframework.jdbc.core.namedparam.SqlParameterSource; class JDBCTest { private ApplicationContext c = null; private JdbcTemplate jdbcTemplate; private Dao dao; private NamedParameterJdbcTemplate namedParameterJdbcTemplate; { c = new ClassPathXmlApplicationContext("jdbc.xml"); jdbcTemplate = (JdbcTemplate) c.getBean("JdbcTemplate"); dao = c.getBean(Dao.class); namedParameterJdbcTemplate=c.getBean(NamedParameterJdbcTemplate.class); } /* * 使用namedParameterJdbcTemplate插入数据 */ @Test public void test() { String sql="insert into m1(name,password) values(:name,:password)"; Map<String, Object> pMap = new HashMap<>(); pMap.put("name", "小莫"); pMap.put("password", "123"); namedParameterJdbcTemplate.update(sql, pMap); // 不推荐使用 // Person person = new Person(); // person.setName("小莫"); // person.setPassword("123"); // SqlParameterSource parameterSource = new BeanPropertySqlParameterSource(person); // namedParameterJdbcTemplate.update(sql, parameterSource); } @Test public void dao() { System.out.println(dao.get(1)); } /* * 获取单个列的值,或统计查询 */ @Test public void huoqu1() { String sql ="select count(id) from m1"; long count =jdbcTemplate.queryForObject(sql, long.class); System.out.println(count); } /* * 查到实体类集合,不调用queryforlist */ @Test public void list() { String sql="select id, name, password from m1 where id > ?"; RowMapper<Person> rowMapper=new BeanPropertyRowMapper<>(Person.class); List<Person> persons=jdbcTemplate.query(sql, rowMapper,1); System.out.println(persons); } /* *从数据库中获取一条记录,实际得到对应的一个对象 注意不是调用 queryForObject(String sql,Class<Employee> requiredType,Object...args)方法! 而需要调用queryForObject(String sql,RowMapper<Employee> rowMapper,Object...args) 1.其中的 RowMapper 指定如何去映射结果集的行,常用的实现类为 BeanPropertyRowMapper 2.使用 SQL 中列的别名完成列名和类的属性名的映射.例如last_name lastName */ @Test public void huoqu() { String sql="select id, name, password from m1 where id = ?"; RowMapper<Person> rowMapper=new BeanPropertyRowMapper<>(Person.class); Person person = jdbcTemplate.queryForObject(sql, rowMapper,56); System.out.println(person); } /* * 批量更新 */ @Test public void batchUpdateTest() { String sql="insert into m1(name,password) values(?,?)"; List<Object[]> batchArgs = new ArrayList<>(); batchArgs.add(new Object[] {"A","123"}); batchArgs.add(new Object[] {"B","123"}); batchArgs.add(new Object[] {"C","123"}); jdbcTemplate.batchUpdate(sql,batchArgs); } /* * 执行insert,update, delete */ @Test public void updateTest() { String sql="update m1 set name= ? where id = ?"; jdbcTemplate.update(sql, "mmm",1); } @Test public void testDataSource() throws SQLException { DataSource dataSource=c.getBean(DataSource.class); System.out.println(dataSource.getConnection()); } }