35.Spring-jdbc支持.md

1.JdbcTemplate类

传统的jdbc开始，需要对Connection、Stream的创建、使用和关闭一一操作。开发负责，代码耦合。在Spring中提供JdbcTemplate简化开发。配合连接池数据库的jdbc操作将和简单

1.1导入jar包

其中，tx是事务管理，接下来用。这里咱不用理会。

1.2创建Dao对象

创建Dao对象，在Dao对象中通过DataSource类来管理连接，通过JdbcTemplate类来处理sql。注意DataSource类是：javax.sql.DataSource

import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;
import java.util.Map;

/**
 * Created by liyue on 2016/11/30.
 */
public class PersonDao
{
    private JdbcTemplate jdbcTemplate;

    public JdbcTemplate getJdbcTemplate()
    {
        return jdbcTemplate;
    }

    public void setJdbcTemplate(JdbcTemplate jdbcTemplate)
    {
        this.jdbcTemplate = jdbcTemplate;
    }

    public void save(String sql)
    {
        System.out.println("保存开始:");
        //插入、保存和更新这一类都是update
        jdbcTemplate.update(sql);
        System.out.println("保存结束");
    }

    public void queryForList()
    {
        String sql = "SELECT * FROM role LIMIT 100;";
        List<Map<String, Object>> list = jdbcTemplate.queryForList(sql);
        System.out.println(list);
    }

    public void queryById(int id)
    {
        String sql = "SELECT * FROM role  WHERE r_id = " + String.valueOf(id) + ";";
        Map<String, Object> m = jdbcTemplate.queryForMap(sql);
        System.out.println(m);
    }
}

然后配置xml文件：

<?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"
       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/tx        
       http://www.springframework.org/schema/tx/spring-tx.xsd        http://www.springframework.org/schema/aop        http://www.springframework.org/schema/aop/spring-aop.xsd">    <!--数据源：c3p0连接池-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
        <property name="jdbcUrl" value="jdbc:mysql:///hi"></property>
        <property name="user" value="root"></property>
        <property name="password" value="root"></property>
        <property name="initialPoolSize" value="3"></property>
    </bean>
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"></property>
    </bean>    <!--Dao对象-->
    <bean id="personDao" class="per.liyue.spring.jdbc_base.PersonDao">
        <property name="jdbcTemplate" ref="jdbcTemplate"></property>
    </bean>
</beans>

最后写测试调用例子

package per.liyue.spring.jdbc_base;

import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;
import java.util.Map;

/**
 * Created by liyue on 2016/11/30.
 */
public class PersonDao
{
    private JdbcTemplate jdbcTemplate;

    public JdbcTemplate getJdbcTemplate()
    {
        return jdbcTemplate;

    }

    public void setJdbcTemplate(JdbcTemplate jdbcTemplate)
    {
        this.jdbcTemplate = jdbcTemplate;

    }

    public void save(String sql)
    {
        System.out.println("保存开始:");
        //插入、保存和更新这一类都是update        jdbcTemplate.update(sql);
        System.out.println("保存结束");

    }

    public void queryForList()
    {
        String sql = "SELECT * FROM role LIMIT 100;";
        List<Map<String, Object>> list = jdbcTemplate.queryForList(sql);
        System.out.println(list);

    }

    public void queryById(int id)
    {
        String sql = "SELECT * FROM role  WHERE r_id = " + String.valueOf(id) + "; ";
        Map<String, Object> m = jdbcTemplate.queryForMap(sql);
        System.out.println(m);

    }

}

1.3将上述例子封装后

增加一个查询结果类

package per.liyue.spring.jdbc_base;

/**
 * Created by liyue on 2016/11/30.
 */
public class Role
{
    private int roleId;

    public int getRoleId()
    {
        return roleId;
    }

    public void setRoleId(int roleId)
    {
        this.roleId = roleId;
    }

    public String getRoleName()
    {
        return roleName;
    }

    public void setRoleName(String roleName)
    {
        this.roleName = roleName;
    }

    private String roleName;

    @Override
    public String toString()
    {
        return "roleId: " + roleId + " roleName: " + roleName;
    }
}

改造Dao类

package per.liyue.spring.jdbc_base;

import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import java.util.Map;

/**
 * Created by liyue on 2016/11/30.
 */
public class PersonDao
{
    private JdbcTemplate jdbcTemplate;

    public JdbcTemplate getJdbcTemplate()
    {
        return jdbcTemplate;
    }

    public void setJdbcTemplate(JdbcTemplate jdbcTemplate)
    {
        this.jdbcTemplate = jdbcTemplate;
    }

    public void save(String sql)
    {
        System.out.println("保存开始:");        //插入、保存和更新这一类都是update
        jdbcTemplate.update(sql);
        System.out.println("保存结束");
    }

    public void queryForList()
    {
        String sql = "SELECT * FROM role LIMIT 100;";
        List<Map<String, Object>> list = jdbcTemplate.queryForList(sql);
        System.out.println(list);
    }

    public Role queryById(int id)
    {
        String sql = "SELECT * FROM role  WHERE r_id = " + String.valueOf(id) + ";";        /*        简单查询        Map<String, Object>m = jdbcTemplate.queryForMap(sql);        System.out.println(m);        */        /*        封装查询         */
        List<Role> list = jdbcTemplate.query(sql, new MyResult());
        return ((list != null) && (list.size() > 0)) ? list.get(0) : null;
    }

    class MyResult implements RowMapper<Role>
    {
        @Override
        public Role mapRow(ResultSet resultSet, int i) throws SQLException
        {
            Role role = new Role();
            role.setRoleId(resultSet.getInt("r_id"));
            role.setRoleName(resultSet.getString("r_name"));
            return role;
        }
    }
}

package per.liyue.spring.jdbc_base;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * Created by liyue on 2016/11/30.
 */
public class App
{
    private ApplicationContext applicationContext = new ClassPathXmlApplicationContext("per/liyue/spring/jdbc_base/applicationContext.xml");

    @Test
    public void testSave()
    {
        System.out.println("开始:");
        PersonDao personDao = applicationContext.getBean("personDao", PersonDao.class);
        String sql = "INSERT INTO role(r_name) VALUE('架构')";
        personDao.save(sql);
        System.out.println("结束");
    }

    @Test
    public void find100()
    {
        System.out.println("开始:");
        PersonDao personDao = applicationContext.getBean("personDao", PersonDao.class);
        personDao.queryForList();
        System.out.println("结束");
    }

    @Test
    public void findById()
    {
        System.out.println("开始:");
        PersonDao personDao = applicationContext.getBean("personDao", PersonDao.class);
        Role role = personDao.queryById(1);
        System.out.println(role);
        System.out.println("结束");
    }
}

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