案例鏈接：鏈接: https://pan.baidu.com/s/1kPzTOknuRK6a8tPqT54REg
提取碼: szr6
步驟1:
在src下新建一個(gè)applicationContext.xml文件辣吃，有幾種配置數(shù)據(jù)庫連接池的方式邑茄，以下有幾種連接池可選擇：Spring自帶的連接池遵岩、DBCP 連接池以及C3P0 連接池，我們以C3P0連接池為例案狠。
具體配置如下：
<?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:aop="http://www.springframework.org/schema/aop"
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/aop
http://www.springframework.org/schema/aop/spring-aop.xsd">
<!-- 注解掃描 -->
<context:component-scan base-package="com.hello"/>
<!-- Spring 自帶的連接池
DriverClassName 用來配置驅(qū)動(dòng)名字
Url 數(shù)據(jù)庫
Username 用戶名
Password 密碼
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
<property name="url" value="jdbc:mysql://10.25.161.7:3306/jss"></property>
<property name="username" value="root"></property>
<property name="password" value="root"></property>
</bean>
-->
<!-- 使用 DBCP 連接池
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
<property name="url" value="jdbc:mysql://10.25.161.7:3306/jss"></property>
<property name="username" value="root"></property>
<property name="password" value="root"></property>
</bean>
-->
<!-- 使用 C3P0 連接池 -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="driverClass" value="com.mysql.jdbc.Driver"></property>
<property name="jdbcUrl" value="jdbc:mysql://localhost:3306/cz3"></property>
<property name="user" value="root"></property>
<property name="password" value="root"></property>
</bean>
<!-- 配置 JDBC 模板 -->
<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource"></property>
</bean>
</beans>
步驟2：
在com.hello.pojo包下新建User類剖淀，字段和數(shù)據(jù)庫表中的字段一樣
package com.hello.pojo;
public class User {
private Integer id;
private String username;
private String password;
public User() {
super();
}
public User(Integer id, String username, String password) {
super();
this.id = id;
this.username = username;
this.password = password;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
@Override
public String toString() {
return "User [id=" + id + ", username=" + username + ", password=" + password + "]";
}
}
步驟3：
在com.hello.mapper包下新建MyRowMapper類實(shí)現(xiàn)RowMapper接口纲堵，重寫mapRow方法，指定返回User對(duì)象棍辕，這個(gè)在Dao層的時(shí)候查詢返回對(duì)象或者對(duì)象集合需要用到暮现。
package com.hello.Mapper;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.springframework.jdbc.core.RowMapper;
import com.hello.pojo.User;
public class MyRowMapper implements RowMapper<User>{
@Override
public User mapRow(ResultSet resultSet, int i) throws SQLException {
//獲取結(jié)果集中的數(shù)據(jù)
int id = resultSet.getInt("id");
String username = resultSet.getString("username");
String password = resultSet.getString("password");
//把數(shù)據(jù)封裝成User對(duì)象
User user = new User();
user.setId(id);
user.setUsername(username);
user.setPassword(password);
return user;
}
}
步驟4：
在com.hello.dao包下新建一個(gè)UserDao接口以及實(shí)現(xiàn)類UserDaoImpl
UserDao接口代碼：
package com.hello.dao;
import java.util.List;
import com.hello.pojo.User;
public interface UserDao {
//通過id查找User
public User findUserById(Integer id);
//查詢?nèi)縐ser
public List<User> selectAllUser();
//通過id查找username
public String findNameById(Integer id);
}
UserDaoImpl實(shí)現(xiàn)類代碼：
（里面舉例了查詢返回結(jié)果的3種情況：返回某個(gè)值、返回某個(gè)對(duì)象楚昭、返回某個(gè)對(duì)象集合）
package com.hello.dao;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Component;
import com.hello.Mapper.MyRowMapper;
import com.hello.pojo.User;
@Component("UserDao")
public class UserDaoImpl implements UserDao {
@Autowired
private JdbcTemplate jdbcTemplate;
/* 查詢返回某一個(gè)值!! */
// 通過id查找username
@Override
public String findNameById(Integer id) {
String sql = "select username from user where id = ?";
String name = jdbcTemplate.queryForObject(sql, String.class, id);
return name;
}
/* 查詢返回單個(gè)對(duì)象Ｆ艽！ */
// 通過id查找User
@Override
public User findUserById(Integer id) {
String sql = "select * from user where id = ?";
User user = jdbcTemplate.queryForObject(sql, new MyRowMapper(), id);
return user;
}
/* 查詢返回對(duì)象集合８塘幅！ */
// 查詢?nèi)縐ser
@Override
public List<User> selectAllUser() {
String sql = "select * from user";
List<User> userList = jdbcTemplate.query(sql, new MyRowMapper());
return userList;
}
}
上面的出現(xiàn)的
@Autowired
private JdbcTemplate jdbcTemplate;
是自動(dòng)裝載xml文件中的bean類昔案，得到一個(gè)Spring的JdbcTemplate對(duì)象，通過這個(gè)對(duì)象可以調(diào)用函數(shù)進(jìn)行增刪改查等操作晌块。
步驟5：
完成以上步驟就可以進(jìn)行測(cè)試了爱沟，新建測(cè)試類SpringTest，分別對(duì)Dao層的三個(gè)方法進(jìn)行測(cè)試
package com.hello.test;
import java.util.List;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import com.hello.dao.UserDao;
import com.hello.pojo.User;
@ContextConfiguration("classpath:applicationContext.xml")
@RunWith(SpringJUnit4ClassRunner.class)
public class SpringTest {
@Autowired
private UserDao userDao;
//通過id查找User
@Test
public void findUserById() {
User user = userDao.findUserById(1);
System.out.println(user);
}
//查詢?nèi)縐ser
@Test
public void selectAllUser(){
List<User> userList = userDao.selectAllUser();
for (User user : userList) {
System.out.println(user);
}
}
//通過id查找username
@Test
public void findNameById(){
String name = userDao.findNameById(1);
System.out.println(name);
}
}
測(cè)試運(yùn)行findUserById()方法,運(yùn)行結(jié)果：
測(cè)試結(jié)果.png
