Spring整合JDBCTemplate

灰太狼 2022-05-16 23:04 240阅读 0赞

#### Spring整合JDBC ####

Spring提供了很多模板整合Dao技术，包括JDBC,Hibernate，MyBatis，JPA等  
![这里写图片描述][70]  
spring中提供了一个可以操作数据库的对象.对象封装了jdbc技术，JDBCTemplate是JDBC的一个模板对象，与DBUtils中的QueryRunner非常相似。本文就JDBCTemplate进行相应的阐述及代码演示

#### 准备工作 ####

*  表设计  
    ![这里写图片描述][70 1]
 *  准备User实体类

package cn.itcast.bean;
    
    public class User { 
        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 "User [id=" + id + ", name=" + name + "]";
        }
    }

*  导包  
    基础包4个+日志包2个+spring-test，spring-aop，junit4类库+c3p0连接池，JDBC驱动+spring-jdbc，spring-tx事务  
    ![这里写图片描述][70 2]
 *  编写Dao层代码

//Dao层接口
    package cn.itcast.a_jdbctemplate;
    import java.util.List;
    import cn.itcast.bean.User;
    
    public interface UserDao {
        //增
        void save(User u);
        //删
        void delete(Integer id);
        //改
        void update(User u);
        //通过ID查找
        User getById(Integer id);
        //查找总记录数
        int getTotalCount();
        //查询所有
        List<User> getAll();
    }

Spring中提供了一个JdbcDaoSupport类，Dao层继承该类后，不需要手动准备JDBC模板，直接根据DataSource创建JDBC模板，从父类方法中直接获得JDBCTemplate对象。

//Dao层实现类
    package cn.itcast.a_jdbctemplate;
    
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.util.List;
    import org.springframework.jdbc.core.JdbcTemplate;
    import org.springframework.jdbc.core.RowMapper;
    import org.springframework.jdbc.core.support.JdbcDaoSupport;
    
    import cn.itcast.bean.User;
    //使用JDBC模板实现增删改查，继承了JdbcDaoSupport类。
    public class UserDaoImpl extends JdbcDaoSupport implements UserDao { 
        @Override
        public void save(User u) {
            String sql = "insert into t_user values(null,?) ";
            super.getJdbcTemplate().update(sql, u.getName());
        }
        @Override
        public void delete(Integer id) {
            String sql = "delete from t_user where id = ? ";
            super.getJdbcTemplate().update(sql,id);
        }
        @Override
        public void update(User u) {
            String sql = "update t_user set name = ? where id=? ";
            super.getJdbcTemplate().update(sql, u.getName(),u.getId());
        }
        @Override
        public User getById(Integer id) {
            String sql = "select * from t_user where id = ? ";
            return super.getJdbcTemplate().queryForObject(sql,new RowMapper<User>(){
                @Override
                public User mapRow(ResultSet rs, int arg1) throws SQLException {
                    User u = new User();
                    u.setId(rs.getInt("id"));
                    u.setName(rs.getString("name"));
                    return u;
                }}, id);
    
        }
        @Override
        public int getTotalCount() {
            String sql = "select count(*) from t_user ";
            Integer count = super.getJdbcTemplate().queryForObject(sql, Integer.class);
            return count;
        }
    
        @Override
        public List<User> getAll() {
            String sql = "select * from t_user ";
            List<User> list = super.getJdbcTemplate().query(sql, new RowMapper<User>(){
                @Override
                public User mapRow(ResultSet rs, int arg1) throws SQLException {
                    User u = new User();
                    u.setId(rs.getInt("id"));
                    u.setName(rs.getString("name"));
                    return u;
                }});
            return list;
        }
    }

*  配置文件  
    通过读取外部的Properties文件，来加载连接数据库的参数值

jdbc.jdbcUrl=jdbc:mysql:///hibernate_32
    jdbc.driverClass=com.mysql.jdbc.Driver
    jdbc.user=root
    jdbc.password=1234

配置文件

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd ">
    
    
    <context:property-placeholder location="classpath:db.properties" />
    
    
    <bean name="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" >
        <property name="jdbcUrl" value="${jdbc.jdbcUrl}" ></property>
        <property name="driverClass" value="${jdbc.driverClass}" ></property>
        <property name="user" value="${jdbc.user}" ></property>
        <property name="password" value="${jdbc.password}" ></property>
    </bean>
    
    
    
    
    
    <bean name="userDao" class="cn.itcast.a_jdbctemplate.UserDaoImpl" >
        
        
        <property name="dataSource" ref="dataSource" ></property>
    </bean>
    </beans>

测试

package cn.itcast.a_jdbctemplate;
    
    import javax.annotation.Resource;
    
    import org.junit.Test;
    import org.junit.runner.RunWith;
    import org.springframework.test.context.ContextConfiguration;
    import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
    
    import cn.itcast.bean.User;
    
    //演示JDBC模板
    @RunWith(SpringJUnit4ClassRunner.class)
    @ContextConfiguration("classpath:applicationContext.xml")
    public class Demo { 
        @Resource(name="userDao")
        private UserDao ud;
    
        @Test
        public void fun1() throws Exception{
            User u = new User();
            u.setName("tom");
            ud.save(u);
        }
        @Test
        public void fun2() throws Exception{
            User u = new User();
            u.setId(2);
            u.setName("jack");
            ud.update(u);
    
        }
        @Test
        public void fun3() throws Exception{
            ud.delete(2);
        }
        @Test
        public void fun4() throws Exception{
            System.out.println(ud.getTotalCount());
        }
        @Test
        public void fun5() throws Exception{
            System.out.println(ud.getById(1));
        }
        @Test
        public void fun6() throws Exception{
            System.out.println(ud.getAll());
        }
    }

[70]: /images/20220517/211f513c47f24f238a308d46dc68ec2e.png
[70 1]: /images/20220517/415d713599064def8f26976fe3df8c22.png
[70 2]: /images/20220517/3acdefe5033e42869384ccc5929ce9ef.png