版权声明:本文为博主原创文章,未经允许不得转载。 https://blog.csdn.net/qq_24672657/article/details/83213166
传统方式和spring jdbcTemplate方式 访问数据库
环境准备
导入依赖
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
创建数据库
CREATE DATABASE spring_data
CREATE TABLE student(
id int not NULL auto_increment,
name VARCHAR(20) NOT NULL,
age int not null,
primary KEY(id)
);
开发JDBCUtil工具类
获取Connection
jdbc.url= jdbc:mysql://localhost:3306/spring_data
jdbc.user = root
jdbc.password = root
jdbc.driverClass = com.mysql.jdbc.Driver
package com.dsdj.util;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;
/**
* @ClassName JDBCUtil
* @Description JDBC工具类
* @Author dsdj
* @Date 2018/10/20 上午9:17
* @Version 1.0
**/
public class JDBCUtil {
/**
* 获取connection
* @return
*/
public static Connection getConnection() throws Exception {
InputStream resourceAsStream = ClassLoader.getSystemClassLoader().getResourceAsStream("db.properties");
Properties properties = new Properties();
properties.load(resourceAsStream);
String url = properties.getProperty("jdbc.url");
String user = properties.getProperty("jdbc.user");
String password = properties.getProperty("jdbc.password");
String driverClass = properties.getProperty("jdbc.driverClass");
Class.forName(driverClass);
Connection connection = DriverManager.getConnection(url, user, password);
return connection;
}
public void release(ResultSet resultSet,
Statement statement, Connection connection){
if (resultSet != null){
try {
resultSet.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (statement != null){
try {
statement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (connection != null) {
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
测试类
public class TestJDBCUtil {
@Test
public void testGetConnetion() throws Exception {
Connection connection = JDBCUtil.getConnection();
Assert.assertNotNull(connection);
}
}
测试通过
数据库访问层
实体类
package com.dsdj.domain;
/**
* @ClassName Student
* @Description Student 实体类
* @Author dsdj
* @Date 2018/10/20 上午10:10
* @Version 1.0
**/
public class Student {
/**
* 主键字段
*/
private int id;
/**
* 姓名
*/
private String name;
/**
* 年龄
*/
private int age;
public Student(int id, String name, int age) {
this.id = id;
this.name = name;
this.age = age;
}
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 int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "Student{" +
"id=" + id +
", name='" + name + '\'' +
", age=" + age +
'}';
}
}
dao接口
package com.dsdj.dao;
import com.dsdj.domain.Student;
import java.util.List;
/**
* @ClassName StudentDAO
* @Description TODO
* @Author dsdj
* @Date 2018/10/20 上午10:13
* @Version 1.0
**/
public interface StudentDAO {
/**
* 查询所有学生
* @return 所有学生
*/
List<Student> query();
int save(Student student);
}
package com.dsdj.dao;
import com.dsdj.domain.Student;
import com.dsdj.util.JDBCUtil;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
/**
* @ClassName StudentDAOImpl
* @Description Student访问接口实现类:通过最原始的JDBC访问方式
* @Author dsdj
* @Date 2018/10/20 上午10:15
* @Version 1.0
**/
public class StudentDAOImpl implements StudentDAO {
@Override
public List<Student> query() {
List<Student> students = new ArrayList<>();
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
String sql = "select * from student";
try {
connection = JDBCUtil.getConnection();
preparedStatement = connection.prepareStatement(sql);
resultSet = preparedStatement.executeQuery();
while (resultSet.next()){
students.add(new Student(resultSet.getInt("id"),
resultSet.getString("name"),
resultSet.getInt("age")));
}
}catch (Exception e){
e.printStackTrace();
}finally {
JDBCUtil.release(resultSet,preparedStatement,connection);
}
return students;
}
@Override
public int save(Student student) {
List<Student> students = new ArrayList<>();
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
String sql = "insert into student (name,age) values (?,?)";
int i =0;
try {
connection = JDBCUtil.getConnection();
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1,student.getName());
preparedStatement.setInt(2,student.getAge());
i = preparedStatement.executeUpdate();
}catch (Exception e){
e.printStackTrace();
}finally {
JDBCUtil.release(resultSet,preparedStatement,connection);
}
return i;
}
}
测试类
package com.dsdj.dao;
import com.dsdj.domain.Student;
import org.junit.Assert;
import org.junit.Test;
import javax.sound.midi.Soundbank;
import java.util.List;
/**
* @ClassName TestStudentDAOImpl
* @Description TODO
* @Author dsdj
* @Date 2018/10/20 上午10:29
* @Version 1.0
**/
public class TestStudentDAOImpl {
@Test
public void testQuery(){
StudentDAO studentDAO = new StudentDAOImpl();
List<Student> query = studentDAO.query();
for (Student s:query){
System.out.println(s.toString());
}
Assert.assertNotNull(query);
}
@Test
public void testSave(){
StudentDAO studentDAO = new StudentDAOImpl();
int i = studentDAO.save(new Student(2, "zhao", 23));
Assert.assertEquals(1,i);
}
}
测试成功
总结
上面就是原始的JDBC数据访问的原始方法
可以发现dao实现类存在许多重复的代码
使用原始的方法开发太慢,太繁琐了
使用Spring JdbcTemplate
搭建环境
添加依赖
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>4.3.18.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.3.18.RELEASE</version>
</dependency>
添加配置文件 bean.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"
xmlns:tx="http://www.springframework.org/schema/tx"
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
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd">
<context:component-scan base-package="com.dsdj.*"></context:component-scan>
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="url" value="jdbc:mysql://localhost:3306/spring_data?useSSL=true"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
</bean>
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"/>
</bean>
</beans>
StudentDaoJDBCTemplateImpl类实现dao接口
package com.dsdj.dao;
import com.dsdj.domain.Student;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowCallbackHandler;
import org.springframework.stereotype.Repository;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
/**
* @ClassName StudentDaoJDBCTemplateImpl
* @Description TODO
* @Author dsdj
* @Date 2018/10/20 下午2:02
* @Version 1.0
**/
@Repository(value = "studentDaoJDBCTemplateImpl")
public class StudentDaoJDBCTemplateImpl implements StudentDAO {
@Autowired
private JdbcTemplate jdbcTemplate;
@Override
public List<Student> query() {
/**
* 使用JDBCtemplate就不需要管理connection了
*/
final List<Student> students = new ArrayList<>();
String sql = "select * from student";
jdbcTemplate.query(sql, new RowCallbackHandler() {
@Override
public void processRow(ResultSet resultSet) throws SQLException {
while (resultSet.next()){
students.add(new Student(resultSet.getInt("id"),
resultSet.getString("name"),
resultSet.getInt("age")));
}
}
});
return students;
}
@Override
public int save(Student student) {
String sql = "insert into student(name, age) values(?,?)";
int update = jdbcTemplate.update(sql, new Object[]{student.getName(), student.getAge()});
return update;
}
}
测试类
package com.dsdj;
import com.dsdj.dao.StudentDAO;
import com.dsdj.domain.Student;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;
import javax.sql.DataSource;
import java.util.List;
/**
* @ClassName TestDataSource
* @Description TODO
* @Author dsdj
* @Date 2018/10/20 上午10:57
* @Version 1.0
**/
public class TestDataSource {
ApplicationContext ctx = null;
private StudentDAO studentDAO;
@Before
public void setUp(){
System.out.println("setup");
ctx = new ClassPathXmlApplicationContext("bean.xml");
studentDAO = (StudentDAO) ctx.getBean("studentDaoJDBCTemplateImpl");
}
@After
public void after(){
ctx = null;
System.out.println("close");
}
@Test
public void testDataSource(){
DataSource dataSource = (DataSource) ctx.getBean("dataSource");
Assert.assertNotNull(dataSource);
}
@Test
public void testJdbcTemplate(){
JdbcTemplate jdbcTemplate = (JdbcTemplate) ctx.getBean("jdbcTemplate");
Assert.assertNotNull(jdbcTemplate);
}
@Test
public void textQuery(){
List<Student> query = studentDAO.query();
for (Student s:query){
System.out.println(s.toString());
}
}
}
测试成功
总结
使用使用spring自带的datasource省去了对connection的管理,使用JDBCTemlate和原生的方式有一定的改进,JDBCTemlate只是对原生的方式进行了包装,但是在dao层的代码还是很多。
下篇文章将介绍spring data访问数据库的优势。