介绍jdbc访问数据库
依赖:
spring-context spring-jdbc c3p0 mysql-connector-java
详细:
User.java:
package com.shuoeasy.test; public class User { private int id; private String name; private double money; 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 double getMoney() { return money; } public void setMoney(double money) { this.money = money; } @Override public String toString() { return "User [id=" + id + ", name=" + name + ", money=" + money + "]"; } }
JDBCTest.java:
package com.shuoeasy.test;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
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 junit.framework.TestCase;
public class JDBCTest extends TestCase {
private ApplicationContext ctx = null;
private JdbcTemplate jdbcTemplate;
{
this.ctx = new ClassPathXmlApplicationContext("bean.xml");
this.jdbcTemplate = (JdbcTemplate) this.ctx.getBean("jdbcTemplate");
}
/**
* 测试连接数据库
*/
@Test
public void testDataSource() throws SQLException{
DataSource dataSource = (DataSource) ctx.getBean("dataSource");
System.out.println(dataSource.getConnection());
}
/**
* 测试修改一条数据
*/
@Test
public void testUpdate(){
String sql = "UPDATE user SET money=money+1 WHERE id=?";
jdbcTemplate.update(sql,1);
}
/**
* 测试插入修改jdbcTemplate
*/
@Test
public void testBatchInsert(){
System.out.println("批量插入数据");
String sql = "INSERT INTO user(name,money) VALUES(?,?)";
List<Object[]> batchArgs = new ArrayList<Object[]>();
batchArgs.add(new Object[]{"用户1",0});
batchArgs.add(new Object[]{"用户2",0});
batchArgs.add(new Object[]{"用户3",0});
int[] num = jdbcTemplate.batchUpdate(sql,batchArgs);
System.out.println("受影响行数:" + Arrays.asList(num));
}
/**
* 从数据库中获取一条记录,并返回对象
*/
@Test
public void testQueryForObject(){
String sql = "SELECT id,name,money FROM user WHERE id=?";
BeanPropertyRowMapper<User> rowMapper = new BeanPropertyRowMapper<User>(User.class);
User user = jdbcTemplate.queryForObject(sql, rowMapper, 1);
System.out.println("user:" + user);
}
/**
* 获取集合
*/
@Test
public void testQueryForList(){
String sql = "SELECT id,name,money FROM user WHERE id>?";
BeanPropertyRowMapper<User> rowMapper = new BeanPropertyRowMapper<>(User.class);
List<User> users = jdbcTemplate.query(sql,rowMapper,1);
System.out.println("users:" + users.size());
}
/**
* 获取一个值,例如总数
*/
@Test
public void testQueryCount(){
String sql = "SELECT count(*) FROM user";
long count = jdbcTemplate.queryForObject(sql, long.class);
System.out.println("count:" + count);
}
}pom.xml:
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.shuoeasy</groupId> <artifactId>test</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>test</name> <url>http://maven.apache.org</url> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> </properties> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>3.8.1</version> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>4.2.6.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-jdbc</artifactId> <version>4.2.6.RELEASE</version> </dependency> <dependency> <groupId>c3p0</groupId> <artifactId>c3p0</artifactId> <version>0.9.1.2</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>6.0.2</version> </dependency> </dependencies> </project>
db.properties:
jdbc.user=root jdbc.password=111111 jdbc.driverClass=com.mysql.jdbc.Driver jdbc.jdbcUrl=jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false jdbc.initialPoolSize=5 jdbc.maxPoolSize=5
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:p="http://www.springframework.org/schema/p"
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-4.2.xsd">
<!-- 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="${jdbc.initialPoolSize}"></property>
<property name="maxPoolSize" value="${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>