String sql ="insert into userinfo(name,pwd) values(?,?)";
PreparedStatement pst=getConnection().prepareStatement(sql);
pst.setString(1，"小明");
pst.setString(2,"123");
pst.executeUpdate();
小伙子给你写了一个通用的增删改查的工具类，你那样写太麻烦
资源文件jdbc.properties
jdbc.Driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/xxx
jdbc.username=root
jdbc.password=root
package com.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import org.apache.commons.beanutils.BeanUtils;
import org.apache.log4j.Logger;
public class BaseDao {
private static String DRIVDR;
private static String URL;
private static String USER;
private static String PWD;
private static Connection connection;
private static Properties properties = new Properties();
private static Logger logger = Logger.getLogger(BaseDao.class);
private static PreparedStatement pst;
private static ResultSet rs;
private static final String CLASS_NOT_EXCEPTION = "驱动加载失败";
static {
try {
properties.load(BaseDao.class.getResourceAsStream("/jdbc.properties"));
DRIVDR = properties.getProperty("jdbc.Driver");
URL = properties.getProperty("jdbc.url");
USER = properties.getProperty("jdbc.username");
PWD = properties.getProperty("jdbc.password");
Class.forName(DRIVDR);
} catch (Exception e) {
logger.debug(CLASS_NOT_EXCEPTION + e.getMessage());
}
}
/**
* 通用的增删改
*
* @param sql
* @param args
* @return
*/
public static int executeCommand(String sql, Object... args) {
int m = 0;
try {
initPreparedStatement(sql, args);
m = pst.executeUpdate();
} catch (Exception e) {
logger.debug("执行增、删、该。错误。。请检查preparedStatement参数。。。"+e.getMessage());
} finally {
closeAll(null, pst, connection);
}
return m;
}
private static PreparedStatement initPreparedStatement(String sql,Object...args){
try {
pst=getConnection().prepareStatement(sql);
if(args!=null){
for(int i=0;i pst.setObject(i+1, args[i]);
}
}
} catch (Exception e) {
logger.debug("为pst对象赋值错误。。请检查preparedStatement参数。。。"+e.getMessage());
}
return pst;
}
/**
* 通用的执行聚合函数
* @param sql
* @param args
* @return
*/
public static int executeScalare(String sql,Object...args){
int count=0;
initPreparedStatement(sql, args);
try {
rs=pst.executeQuery();
if(rs.next()){
count=rs.getInt(1);
}
} catch (SQLException e) {
logger.debug("执行聚合函数出错。。。请检查preparedStatement参数。。。"+e.getMessage());
}finally{
closeAll(rs, pst, connection);
}
return count;
}
/**
* 根据id查询单个对象
* @param sql
* @param clazz
* @param args
* @return
*/
public static T findById(String sql,Class clazz,Object...args){
T t = null;
try {
initPreparedStatement(sql, args);
rs = pst.executeQuery();
ResultSetMetaData metaData = rs.getMetaData();
// 以上的代码：获取元数据（各个字段的数据类型）
int count = metaData.getColumnCount();
// 获取字段的数量
if(rs.next()) {
try {
t = clazz.newInstance();// 利用反射自动创建对象的类型的对象 User.class User
// u=new User();
for (int i = 1; i <= count; i++) {
BeanUtils.copyProperty(t, metaData.getColumnName(i), rs.getObject(i));
// 自动获取各个字段的名称并获取该字段的值
}
} catch (Exception e) {
logger.debug("查询单个对象，错误。。请检查preparedStatement参数。。。。"+e.getMessage());
}
}
} catch (SQLException e) {
logger.debug("查询失败。。。。。" + e.getMessage());
}
return t;
}
/**
* 通用的查询
*
* @param sql
* @param clazz
* @param args
* @return
*/
public static List findAll(String sql, Class clazz, Object... args) {
List list = new ArrayList(100);
T t = null;
try {
initPreparedStatement(sql, args);
rs = pst.executeQuery();
ResultSetMetaData metaData = rs.getMetaData();
// 以上的代码：获取元数据（各个字段的数据类型）
int count = metaData.getColumnCount();
// 获取字段的数量
while (rs.next()) {
try {
t = clazz.newInstance();// 利用反射自动创建对象的类型的对象 User.class User
// u=new User();
for (int i = 1; i <= count; i++) {
BeanUtils.copyProperty(t, metaData.getColumnName(i), rs.getObject(i));
// 自动获取各个字段的名称并获取该字段的值
}
} catch (Exception e) {
logger.debug("查询集合，错误。。。。。"+e.getMessage());
}
list.add(t);// 将对象添加到集合中
}
} catch (SQLException e) {
logger.debug("查询失败。。。。。" + e.getMessage());
}
return list;
}
public static Connection getConnection() {
try {
if (connection == null || connection.isClosed()) {
connection = DriverManager.getConnection(URL, USER, PWD);
}
} catch (SQLException e) {
logger.debug("获取connection失败，请检查配置文件！" + e.getMessage());
}
return connection;
}
public static void closeAll(ResultSet rs, PreparedStatement pst, Connection conn) {
if (rs != null)
try {
rs.close();
} catch (SQLException e) {
logger.debug("关闭ResultSet错误。。。。。" + e.getMessage());
}
if (pst != null)
try {
pst.close();
} catch (SQLException e) {
logger.debug("关闭PreparedStatement错误。。。。。" + e.getMessage());
}
if (conn != null)
closeConnection(conn);
}
private static void closeConnection(Connection conn) {
try {
if (!conn.isClosed()) {
conn.close();
}
} catch (SQLException e) {
logger.debug("关闭Connection错误。。。。。" + e.getMessage());
} finally {
conn = null;
}
}
public static void main(String[] args) {
System.out.println(BaseDao.getConnection());
}
}
