Spring_使用 JdbcTemplate和JdbcDaoSupport-代码

Posted 2020-08-05 疯狂的tiger

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-4.1.xsd">

 

<context:component-scan base-package="om.hy.spring.JdbcTemplate">
</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>

</beans>

db.properties

jdbc.user=sems
jdbc.password=iotcomm
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.jdbcUrl=jdbc:mysql://61.131.64.118\:3204/test?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull
jdbc.initPoolSize=5
jdbc.maxPoolSize=10

 

Department.java

package com.atguigu.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.atguigu.spring.jdbc;

import javax.sql.DataSource;

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;

/**
* 不推荐使用 JdbcDaoSupport, 而推荐直接使用 JdbcTempate 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.atguigu.spring.jdbc;

public class Employee {

private Integer id;
private String lastName;
private String email;

private Integer dpetId;

public Integer getId() {
return id;
}

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

public String getLastName() {
return lastName;
}

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

public String getEmail() {
return email;
}

public void setEmail(String email) {
this.email = email;
}

public Integer getDpetId() {
return dpetId;
}

public void setDpetId(Integer dpetId) {
this.dpetId = dpetId;
}

@Override
public String toString() {
return "Employee [id=" + id + ", lastName=" + lastName + ", email="
+ email + ", dpetId=" + dpetId + "]";
}

}

 

EmployeeDao.java

package com.atguigu.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 FROM employees WHERE id = ?";
RowMapper<Employee> rowMapper = new BeanPropertyRowMapper<>(Employee.class);
Employee employee = jdbcTemplate.queryForObject(sql, rowMapper, id);

return employee;
}
}

 

JDBCTest.java

package com.atguigu.spring.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.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;

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 实现类作为参数.
*/
@Test
public void testNamedParameterJdbcTemplate2(){
String sql = "INSERT INTO employees(last_name, email, dept_id) "
+ "VALUES(:lastName,:email,:dpetId)";

Employee employee = new Employee();
employee.setLastName("XYZ");
employee.setEmail("[email protected]");
employee.setDpetId(3);

SqlParameterSource paramSource = new BeanPropertySqlParameterSource(employee);
namedParameterJdbcTemplate.update(sql, paramSource);
}

/**
* 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.
*/
@Test
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);
}

@Test
public void testDepartmentDao(){
System.out.println(departmentDao.get(1));
}

@Test
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)
*/
@Test
public void testQueryForObject2(){
String sql = "SELECT count(id) FROM 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
*/
@Test
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<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
* 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
*/
@Test
public void testQueryForObject(){
String sql = "SELECT id, last_name lastName, email, dept_id as \"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
*/
@Test
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);
}

/**
* 执行 INSERT, UPDATE, DELETE
*/
@Test
public void testUpdate(){
String sql = "UPDATE employees SET last_name = ? WHERE id = ?";
jdbcTemplate.update(sql, "Jack", 5);
}

@Test
public void testDataSource() throws SQLException {
DataSource dataSource = ctx.getBean(DataSource.class);
System.out.println(dataSource.getConnection());
}

}