1.配置文件为：
driver=com.mysql.jdbc.Driver url=jdbc:mysql://localhost:3306/user_info user=root password=root
2.SqlHelper类为：
package com.mysql.JDBC;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.sql.*;
public class SqlHelper
{
//定义变量
private static Connection ct = null;
//大多数情况下用preparedstatement替代statement
private static PreparedStatement ps = null;
private static ResultSet rs = null;
//连接数据库的参数
private static String url = null;
private static String username =null;
private static String driver =null;
private static String passwd =null;
private static CallableStatement cs = null;
public static CallableStatement getCs()
{
return cs;
}
private static Properties pp = null;
private static InputStream fis = null;
//加载驱动，只需要一次，用静态代码块
static
{
try
{
//从dbinfo.properties
pp = new Properties();
fis=SqlHelper.class.getClassLoader().getResourceAsStream("config.properties");
pp.load(fis);
url = pp.getProperty("url");
driver = pp.getProperty("driver");
username = pp.getProperty("user");
passwd = pp.getProperty("password");
Class.forName(driver);
}
catch (Exception e)
{
e.printStackTrace();
}
finally
{
try{
fis.close();
}
catch(IOException e) {e.printStackTrace();}
fis = null;//垃圾回收站上收拾
}
}
//得到连接
public static Connection getConnection()
{
try
{ct = DriverManager.getConnection(url,username,passwd);}
catch(Exception e) {e.printStackTrace();}
return ct;
}
//*************callPro1存储过程函数1*************
public static CallableStatement callPro1(String sql,String[] parameters)
{
try{
ct = getConnection();
cs = ct.prepareCall(sql);
if(parameters!=null){
for(int i=0;i<parameters.length;i++){
cs.setObject(i+1,parameters[i]);
}
}
cs.execute();
}
catch(Exception e) { e.printStackTrace(); throw new RuntimeException(e.getMessage());}
finally
{ close(rs,cs,ct);}
return cs;
}
//*******************callpro2存储过程2************************
public static CallableStatement callPro2(String sql,String[] inparameters,
Integer[] outparameters)
{
try
{
ct = getConnection();
cs = ct.prepareCall(sql);
if(inparameters!=null)
{
for(int i=0;i<inparameters.length;i++)
{
cs.setObject(i+1,inparameters[i]);
}
}
//cs.registerOutparameter(2,oracle.jdbc.OracleTypes.CURSOR);
if(outparameters!=null)
{
for(int i=0;i<outparameters.length;i++)
{
cs.registerOutParameter(inparameters.length+1+i,outparameters[i]);
}
}
cs.execute();
}
catch(Exception e) {
e.printStackTrace(); throw new RuntimeException(e.getMessage());
}
finally
{
}
return cs;
}
/**
*
* @param sql
* @param parameters
* @return
* @author Cally
* @date 2017-8-27 上午10:32:00
* @Description
* @return ResultSet
*/
public static ArrayList<Object[]> executeQuery(String sql,String[] parameters)
{
ArrayList<Object[]> list = null;
try
{
ct=getConnection();
ps=ct.prepareStatement(sql);
if(parameters!=null)
{
for(int i=0;i<parameters.length;i++)
{
ps.setString(i+1,parameters[i]);
}
}
rs = ps.executeQuery();
//得到结果集（rs）的结构
ResultSetMetaData rsmd = rs.getMetaData();
// if(rs.getRow()!=0)
list=new ArrayList<Object[]>();
//通过rsmd可以得到该结果集有多少列
int columnNum = rsmd.getColumnCount();
//从rs中取出数据，并且封装到ArrayList中
while (rs.next()) {
Object []objects = new Object[columnNum];
for(int i = 0; i < objects.length; i++) {
objects[i] = rs.getObject(i + 1);
}
list.add(objects);
}
return list;
}
catch(Exception e)
{
e.printStackTrace();
throw new RuntimeException(e.getMessage());
}
finally
{
close(rs, ps, ct);
}
}
public static Connection getCt()
{
return ct;
}
public static PreparedStatement getPs()
{
return ps;
}
public static ResultSet getRs()
{
return rs;
}
public static void executeUpdate2(String[] sql,String[][] parameters)
{
try
{
ct = getConnection();
ct.setAutoCommit(false);
for(int i=0;i<sql.length;i++)
{
if(null!=parameters[i])
{
ps = ct.prepareStatement(sql[i]);
for(int j=0;j<parameters[i].length;j++)
{
ps.setString(j+1,parameters[i][j]);
}
ps.executeUpdate();
}
}
ct.commit();
}catch (Exception e)
{
e.printStackTrace();
try
{
ct.rollback();
}
catch (SQLException e1)
{
e1.printStackTrace();
}
throw new RuntimeException(e.getMessage());
}finally
{
close(rs,ps,ct);
}
}
//先写一个update、delete、insert
//sql格式：update 表名 set 字段名 =？where 字段=？
//parameter神应该是（”abc“,23）
public static void executeUpdate(String sql,String[] parameters)
{
try
{
ct=getConnection();
ps = ct.prepareStatement(sql);
if(parameters!=null)
{
for(int i=0;i<parameters.length;i++)
{
ps.setString(i+1,parameters[i]);
}
}
ps.executeUpdate();
}
catch(Exception e)
{
e.printStackTrace();//开发阶段
//抛出异常
//可以处理，也可以不处理
throw new RuntimeException(e.getMessage());
}
finally
{
close(rs,ps,ct);
}
}
public static void close(ResultSet rs,Statement ps,Connection ct)
{
//关闭资源(先开后关)
if(rs!=null)
{
try
{
rs.close();
}
catch(SQLException e)
{
e.printStackTrace();
}
rs=null;
}
if(ps!=null)
{
try
{
ps.close();
}
catch(SQLException e)
{
e.printStackTrace();
}
ps=null;
}
if(null!=ct)
{
try
{
ct.close();
}
catch(SQLException e)
{
e.printStackTrace();
}
ct=null;
}
}
public static List<Object> resultSetToList(ResultSet rs) throws java.sql.SQLException {
if (rs == null)
return Collections.emptyList();
ResultSet md = (ResultSet) rs.getMetaData(); //得到结果集(rs)的结构信息，比如字段数、字段名等
int columnCount = ((ResultSetMetaData) md).getColumnCount(); //返回此 ResultSet 对象中的列数
List<Object> list = new ArrayList<Object>();
Map<Object, Object> rowData = new HashMap<Object, Object>();
while (rs.next()) {
rowData = new HashMap<Object, Object>(columnCount);
for (int i = 1; i <= columnCount; i++) {
rowData.put(((ResultSetMetaData) md).getColumnName(i), rs.getObject(i));
}
list.add(rowData);
}
return list;
}
}