例子程序
基本结构
db.properties
jdbc.user=root
jdbc.password=etron
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.jdbcUrl=jdbc:mysql:///spring4
jdbc.initPoolSize=5
jdbc.maxPoolSize=50
Department.java
package com.spring.jdbc;
public class Department {
private Integer id;
private String name;
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;
}
@Override
public String toString() {
return "Department{" +
"id=" + id +
", name='" + name + '\'' +
'}';
}
}
DepartmentDao.java
package com.spring.jdbc;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
import org.springframework.stereotype.Repository;
import javax.sql.DataSource;
/**
* 不推荐使用JdbcDaoSupport,而直接使用JdbcTemplate作为Dao类的成员变量
*/
@Repository
public class DepartmentDao extends JdbcDaoSupport {
@Autowired
public void setDataSource2(DataSource dataSource){
setDataSource(dataSource);
}
public Department get(Integer id){
String sql = "SELECT id, dept_name name FROM departments WHERE id = ?";
RowMapper<Department> rowMapper = new BeanPropertyRowMapper<>(Department.class);
return getJdbcTemplate().queryForObject(sql,rowMapper,id);
}
}
Employee.java
package com.spring.jdbc;
public class Employee {
private Integer id;
private String lastname;
private String email;
private Integer deptId;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getLastname() {
return lastname;
}
public void setLastname(String last_name) {
this.lastname = last_name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public Integer getDeptId() {
return deptId;
}
public void setDeptId(Integer deptId) {
this.deptId = deptId;
}
@Override
public String toString() {
return "Employee{" +
"id=" + id +
", lastname='" + lastname + '\'' +
", email='" + email + '\'' +
", deptId=" + deptId +
'}';
}
}
EmployeeDao.java
package com.spring.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 EmployeeDao {
@Autowired
private JdbcTemplate jdbcTemplate;
public Employee get(Integer id){
String sql = "SELECT id,last_name lastname,email,dept_id \"department.id\" from employees where ID = ? ";
RowMapper<Employee> rowMapper = new BeanPropertyRowMapper<>(Employee.class);
Employee employee = jdbcTemplate.queryForObject(sql,rowMapper,id);
return employee;
}
}
JDBCTest.java
package com.spring.jdbc;
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;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class JDBCTest {
private ApplicationContext ctx = null;
private JdbcTemplate jdbcTemplate;
private EmployeeDao employeeDao;
private DepartmentDao departmentDao;
private NamedParameterJdbcTemplate namedParameterJdbcTemplate;
{
ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
jdbcTemplate = (JdbcTemplate) ctx.getBean("jdbcTemplate");
employeeDao = ctx.getBean(EmployeeDao.class);
departmentDao = ctx.getBean(DepartmentDao.class);
namedParameterJdbcTemplate = ctx.getBean(NamedParameterJdbcTemplate.class);
}
/**
* 使用具名参数时,可以使用update(String sql,SqlParameterSource paramSource)方法进行更新操作
* 1.SQL语句中的参数名和类的属性一致!
* 2.使用SqlParameterSource的BeanPropertySqlParameterSource实现作为参数。
*/
public void testNamedParameterJdbcTemplate2() {
String sql = "INSERT INTO employees(last_name,email, dept_id)" +
" values(:lastname,:email,:deptId)";
Employee employee = new Employee();
employee.setLastname("XYZ");
employee.setEmail("[email protected]");
employee.setDeptId(3);
SqlParameterSource parameterSource = new BeanPropertySqlParameterSource(employee);
namedParameterJdbcTemplate.update(sql,parameterSource);
}
/**
* 可以为参数起名字。
* 1.好处:若有多个参数,则不用再去对应位置,直接对应参数名,便于维护
* 2.缺点:较为麻烦。
*/
public void testNamedParameterJdbcTemplate(){
String sql = "INSERT INTO employees(last_name,email, dept_id) values(:ln,:email,:deptid)";
Map<String,Object> paramMap = new HashMap<>();
paramMap.put("ln","FF");
paramMap.put("email","[email protected]");
paramMap.put("deptid",2);
namedParameterJdbcTemplate.update(sql,paramMap);
}
public void testDepartmentDao(){
System.out.println(departmentDao.get(1));
}
public void testEmployeeDao(){
System.out.println(employeeDao.get(1));
}
/**
* 获取单个列的值,或做统计查询
* 使用 queryForObject(String sql,Class<Long> requiredType);
*/
public void testQueryForObject2(){
String sql = "SELECT count(id) FORM employees";
long count = jdbcTemplate.queryForObject(sql,Long.class);
System.out.println(count);
}
/**
* 查到实体类的集合
* 注意调用的不是queryForList方法
*/
public void testQueryForList(){
String sql = "SELECT id,last_name lastname,email from employees where ID < ? ";
RowMapper<Employee> rowMapper = new BeanPropertyRowMapper<>(Employee.class);
List<Employee> employees = jdbcTemplate.query(sql,rowMapper,5);
System.out.println(employees);
}
/**
* 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<Employees> requiredType, Object...args)方法!
* 而需要调用 queryForObject(String sql,RowMapper<Emplyee> 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BeanPropertyMapper
* 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
* 3.不支持级联属性。JdbcTemplate 到底是一个JDBC的小工具,而不是ORM框架
*/
public void testQueryForObject(){
String sql = "SELECT id,last_name lastname,email,dept_id \"department.id\" from employees where ID = ? ";
RowMapper<Employee> rowMapper = new BeanPropertyRowMapper<>(Employee.class);
Employee employee = jdbcTemplate.queryForObject(sql,rowMapper,1);
System.out.println(employee);
}
/**
* 执行批量更新:批量的INSERT, UPDATE, DELETE
* 最后一个参数是Object[] 的List 类型:因为修改一条记录需要一个Object的数组,那么多条不就需要多个Object的数组吗
*/
public void testBatchUpdate(){
String sql = "INSERT INTO employees(last_name,email,dept_id) values(?,?,?)";
List<Object[]> batchArgs = new ArrayList<>();
batchArgs.add(new Object[]{"AA","[email protected]",1});
batchArgs.add(new Object[]{"BB","[email protected]",2});
batchArgs.add(new Object[]{"CC","[email protected]",3});
batchArgs.add(new Object[]{"DD","[email protected]",3});
batchArgs.add(new Object[]{"EE","[email protected]",2});
jdbcTemplate.batchUpdate(sql,batchArgs);
}
public void testUpdate(){
String sql = "UPDATE employees SET last_name = ? WHERE id = ?";
jdbcTemplate.update(sql,"Jack",2);
}
}
applicationContext.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"
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.xsd">
<context:component-scan base-package="com.spring.jdbc"></context:component-scan>
<!-- 导入资源文件 -->
<context:property-placeholder location="classpath:db.properties"/>
<!-- 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="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
<property name="driverClass" value="${jdbc.driverClass}"></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>
<!--配置 NamedParameterJdbcTemplate , 该对象可以使用具名参数,其没有无参数的狗在其,所以必须为其构造器指定参数-->
<bean id="namedParameterJdbcTemplate"
class = "org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
<constructor-arg ref="dataSource"></constructor-arg>
</bean>
</beans>
package com.spring.jdbc;
public class Main {
public static void main(String[] args){
JDBCTest a = new JDBCTest();
a.testNamedParameterJdbcTemplate2();
}
}