采用c3p0数据库连接池底层是jdbc的数据库的增删改查

1.新建dbutils包，里面是JdbcUtils类：

package cn.com.xxx.xxx.dbutil;

import java.sql.Connection;
import java.sql.SQLException;

import javax.sql.DataSource;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class JdbcUtils {

    /*
     *释放数据库的连接
     *
     */
        public static void releaseConnection(Connection connection){

            try {
                if(connection !=null){
                    connection.close();
                }
            } catch (Exception e) {
              e.printStackTrace();
            }
        }

        private static DataSource dataSource=null;
        static {
            /*
             * 数据源只能被创建一次
             */
            dataSource=new ComboPooledDataSource("stormTest");
        }

        public static Connection getConnection() throws SQLException{
             //dataSource=new ComboPooledDataSource("mvcapp");若要是放在这里就说明，获得一次就创建一下，比较耗费内存
            return dataSource.getConnection();
        }

}

2.c3p0的配置文件:c3p0-config.xml

<?xml version="1.0" encoding="UTF-8"?>

<c3p0-config>

  <named-config name="stormTest"> 

    <property name="user">root</property>
    <property name="password">12345678</property>
    <property name="driverClass">com.mysql.jdbc.Driver</property>
    <property name="jdbcUrl">jdbc:mysql://127.0.0.1:3306/ies?rewriteBatchedStatements=true&amp;useUnicode=true&amp;characterEncoding=utf-8</property>

    <property name="acquireIncrement">5</property>
    <property name="initialPoolSize">10</property>
    <property name="minPoolSize">10</property>
    <property name="maxPoolSize">50</property>

    <property name="maxStatements">20</property>
    <property name="maxStatementsPerConnection">5</property>

  </named-config>
</c3p0-config>

rewriteBatchedStatements=true 这个是配置mysql数据库批量处理（批量插入，删除，更新）的一个配置项

<named-config name="stormTest"> 中的stormTest,要跟JdbcUtils.java中的

 dataSource=new ComboPooledDataSource("stormTest");   构造函数的参数一致
3.写基本的Dao:(包含QueryRunner的批处理方法)

package cn.com.sgcc.gdt.dao;

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.sql.Connection;
import java.util.List;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;

import cn.com.sgcc.gdt.dbutil.JdbcUtils;

public class Dao<T> {

    private QueryRunner queryRunner=new QueryRunner();
    private Class<T> clazz;

    public Dao(){
        Type superClass=getClass().getGenericSuperclass();
        if(superClass instanceof ParameterizedType){
            ParameterizedType parameterizedType= (ParameterizedType) superClass;

            Type[] typeArgs=parameterizedType.getActualTypeArguments();
            if(typeArgs!=null&&typeArgs.length>0){
               if(typeArgs[0] instanceof Class){
                   clazz=(Class<T>) typeArgs[0];
               }
            }
        }
    }
    /*
     *这个方法是只获取，表格中的某一行属性中的某一个属性值，就是返回某一个字段的值，例如返回某一条记录的customerName，或者返回数据表中有多少条记录等。
     */
    public <E> E getForValue(String sql,Object ... args){
        Connection connection=null;
        try {connection=JdbcUtils.getConnection();
            return (E) queryRunner.query(connection, sql, new ScalarHandler(), args);
        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            JdbcUtils.releaseConnection(connection);
        }
        return null;
    }

    /*
     * 该方法是返回一组数据对象实体类，返回T所对应的List，其实质就是查询
     */
    public List<T> getForList(String sql,Object ... agrs ){
        Connection connection=null;
        try {connection=JdbcUtils.getConnection();
            return queryRunner.query(connection, sql, new BeanListHandler<T>(clazz), agrs);
        } catch (Exception e) {
           e.printStackTrace();
        }finally{
            JdbcUtils.releaseConnection(connection);
        }
        return null;
    }
    /*执行查询的语句，结果是返回数据表中的一个对象（一条记录）其实质就是查询！
     */
      public T get(String sql,Object ... agrs){

          Connection connection=null;
          try {connection=JdbcUtils.getConnection();
            return queryRunner.query(connection, sql, new BeanHandler<T>(clazz), agrs);
        } catch (Exception e) {
               e.printStackTrace();
        }finally{
            JdbcUtils.releaseConnection(connection);
        }
         return null;
      }
      /*
       * 该方法封装了INSERT、UPDATE、DELETE操作
       * sql是sql语句
       * args是占位符
       * result 1:代表操作成功; 0:代表操作失败
       */
    public int update(String sql,Object ... args){
        Connection connection=null;
        int result =0;
        try {connection=JdbcUtils.getConnection();
        result=queryRunner.update(connection, sql, args);

        } catch (Exception e) {
           e.printStackTrace();
        }finally{
            JdbcUtils.releaseConnection(connection);
        }
        return result;
    }

    /**
     * 批处理
     * @param sql
     * @param args :二维数组,高维确定执行sql语句的次数，低维是给？赋值
     * @return
     */
    public void batchUpdate(String sql,Object[][] args){
         Connection connection = null;
        //int result = 0;
         try {connection=JdbcUtils.getConnection();
         queryRunner.batch(connection, sql, args);

         } catch (Exception e) {
            e.printStackTrace();
         }finally{
             JdbcUtils.releaseConnection(connection);
         }

    }
}

4.写要查询结果的封装对象javabean，注意：Javabean中的属性需要和查询的表的属性一致(JDBC没有rowmapper,所以对于数据别名可以在sql查询语句中 as ‘新的表头名字’)

package cn.com.sgcc.gdt.bean;

import java.io.Serializable;
import java.util.Date;

/**
 * 当前值(update)
 * @author Joy
 *
 */
public class StatusCurrent implements Serializable{

    /**
     *
     */
    private static final long serialVersionUID = 1L;
    /**监测对象编码*/
    private String MS_NO;
    /**指标编码*/
    private String INDI_NO;
    /**数据类型*/
    private String DATA_TYPE;
    /**数据刷新时间*/
    private Date REFRESH_TIME;
    /**数据值*/
    private Double RVAL;
    public String getMS_NO() {
        return MS_NO;
    }
    public void setMS_NO(String mS_NO) {
        MS_NO = mS_NO;
    }
    public String getINDI_NO() {
        return INDI_NO;
    }
    public void setINDI_NO(String iNDI_NO) {
        INDI_NO = iNDI_NO;
    }
    public String getDATA_TYPE() {
        return DATA_TYPE;
    }
    public void setDATA_TYPE(String dATA_TYPE) {
        DATA_TYPE = dATA_TYPE;
    }
    public Date getREFRESH_TIME() {
        return REFRESH_TIME;
    }
    public void setREFRESH_TIME(Date rEFRESH_TIME) {
        REFRESH_TIME = rEFRESH_TIME;
    }
    public Double getRVAL() {
        return RVAL;
    }
    public void setRVAL(Double rVAL) {
        RVAL = rVAL;
    }
    public StatusCurrent() {
        super();
    }
    @Override
    public String toString() {
        return "StatusCurrent [MS_NO=" + MS_NO + ", INDI_NO=" + INDI_NO
                + ", DATA_TYPE=" + DATA_TYPE + ", REFRESH_TIME=" + REFRESH_TIME
                + ", RVAL=" + RVAL + "]";
    }
    public StatusCurrent(String mS_NO, String iNDI_NO, String dATA_TYPE,
            Date rEFRESH_TIME, Double rVAL) {
        super();
        MS_NO = mS_NO;
        INDI_NO = iNDI_NO;
        DATA_TYPE = dATA_TYPE;
        REFRESH_TIME = rEFRESH_TIME;
        RVAL = rVAL;
    }

}

5.写某个表进行增删改查的dao接口:

package cn.com.sgcc.gdt.dao;

import java.util.List;

import cn.com.sgcc.gdt.bean.StatusCurrent;

public interface StatusCurrentDao {

    public int update(StatusCurrent sd);

    public int save(StatusCurrent sd);

    public void batchUpdate(List<StatusCurrent> sds);

    public void batchSave(List<StatusCurrent> sds);
}

6.5中接口的实现类（批量插入和批量删除，批量更新的代码）：

package cn.com.sgcc.gdt.daoImpl;

import java.util.List;

import cn.com.sgcc.gdt.bean.StatusCurrent;
import cn.com.sgcc.gdt.dao.Dao;
import cn.com.sgcc.gdt.dao.StatusCurrentDao;

public class StatusCurrentDaoJdbcImpl extends Dao<StatusCurrent> implements
        StatusCurrentDao {

    @Override
    public int update(StatusCurrent sc) {
        String sql ="update r_status_curr set data_type=?,rval=?,refresh_time=?  where ms_no=? and indi_no=?";
        return update(sql,sc.getDATA_TYPE(),sc.getRVAL(),sc.getREFRESH_TIME(),sc.getMS_NO(),sc.getINDI_NO());

    }

    @Override
    public int save(StatusCurrent sd) {
        String sql = "insert into r_status_curr(ms_no,data_type,indi_no,rval,refresh_time) values(?,?,?,?,?)";
        return update(sql,sd.getMS_NO(),sd.getDATA_TYPE(),sd.getINDI_NO(),sd.getRVAL(),sd.getREFRESH_TIME());
    }

    @Override
    public void batchUpdate(List<StatusCurrent> sds) {
        String sql ="update r_status_curr set rval=? where ms_no=? and indi_no=? ";
        Object[][] params = new Object[sds.size()][];
        for (int i = 0; i < sds.size(); i++) {
            params[i] = new Object[]{sds.get(i).getRVAL(),sds.get(i).getMS_NO(),sds.get(i).getINDI_NO()};
        }

        batchUpdate(sql, params);
    }

    @Override
    public void batchSave(List<StatusCurrent> sds) {
        String sql = "insert into r_status_curr(ms_no,data_type,indi_no,rval,refresh_time) values(?,?,?,?,?)";
        Object[][] params = new Object[sds.size()][];
        for (int i = 0; i < sds.size(); i++) {
            params[i] = new Object[]{sds.get(i).getMS_NO(),sds.get(i).getDATA_TYPE(),sds.get(i).getINDI_NO(),sds.get(i).getRVAL(),sds.get(i).getREFRESH_TIME()};
        }

        batchUpdate(sql, params);

    }

    /*@Override
    public void batchUpdate(List<StatusCurrent> sds) {
        String sql ="replace into r_status_curr (ms_no,indi_no,data_type,rval,refresh_time) values (?,?,?,?,?)";
        Object[][] params = new Object[sds.size()][];
        for (int i = 0; i < sds.size(); i++) {
            params[i] = new Object[]{sds.get(i).getMS_NO(),sds.get(i).getINDI_NO(),sds.get(i).getDATA_TYPE(),sds.get(i).getRVAL(),sds.get(i).getREFRESH_TIME()};
        }

        batchUpdate(sql, params);
    }*/

}

7.普通调用:

private static StatusCurrentDao statusCurrentDao = new StatusCurrentDaoJdbcImpl();

statusCurrentDao.方法名字()就可以使用了