Question

求JAVA连接SQL数据库的代码

比如一个SQL server的数据库test，现在要一个能嵌入网页的JAVA程序，实现的功能是搜索test库当中一个表的数据并在网页当中显示出来，比如就是搜索表abc中id为1的数据
试着写了一个程序，但嵌入网页后报了好多错……
java.lang.reflect.InvocationTargetException
……一堆错
Caused by: java.lang.ClassCastException: showequip cannot be cast to java.applet.Applet
……又一堆
异常：java.lang.reflect.InvocationTargetException
错误太多，不能全部粘上来，就象征性地挑概括的了，如果不是extends applet的能嵌入网页吗？

Answer 1

package com.conn;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.HashMap;
import java.util.Map;

public class ConPool {

private String strDriverClass;
private String strJdbcUrl;
private String strUserName;
private String strUserPwd;

public ConPool(){
}

public Connection getMyJdbcConn()
{
Connection myConn=null;

try {
Class.forName(this.getStrDriverClass()).newInstance();
//DriverManager.registerDriver (new org.postgresql.Driver());
myConn= DriverManager.getConnection(this.getStrJdbcUrl(),this.getStrUserName(),this.getStrUserPwd());
}catch (Exception ex) {
System.out.print(ex);
}
return myConn;
}

public void closeConn(Connection myConn)
{
if (myConn!=null) {
try{
myConn.close();
myConn=null;
}catch(Exception e){}
}
}

/**
* @return the strDriverClass
*/
public String getStrDriverClass() {
return strDriverClass;
}

/**
* @param strDriverClass the strDriverClass to set
*/
public void setStrDriverClass(String strDriverClass) {
this.strDriverClass = strDriverClass;
}

/**
* @return the strJdbcUrl
*/
public String getStrJdbcUrl() {
return strJdbcUrl;
}

/**
* @param strJdbcUrl the strJdbcUrl to set
*/
public void setStrJdbcUrl(String strJdbcUrl) {
this.strJdbcUrl = strJdbcUrl;
}

/**
* @return the strUserName
*/
public String getStrUserName() {
return strUserName;
}

/**
* @param strUserName the strUserName to set
*/
public void setStrUserName(String strUserName) {
this.strUserName = strUserName;
}

/**
* @return the strUserPwd
*/
public String getStrUserPwd() {
return strUserPwd;
}

/**
* @param strUserPwd the strUserPwd to set
*/
public void setStrUserPwd(String strUserPwd) {
this.strUserPwd = strUserPwd;
}

public static void main(String[] args) {
Connection crmCon=null;
ConPool cp = new ConPool();
// //MySQL数据库
// cp.setStrDriverClass("com.mysql.jdbc.Driver");
// cp.setStrJdbcUrl("jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=gbk");
// cp.setStrUserName("test");
// cp.setStrUserPwd("test");

//postgre数据库
cp.setStrDriverClass("org.postgresql.Driver");
cp.setStrJdbcUrl("jdbc:postgresql://127.0.0.1:5432/test");
cp.setStrUserName("test");
cp.setStrUserPwd("test");

crmCon=cp.getMyJdbcConn();
if (crmCon!=null) {
System.out.println("通过jdbc连接成功！");
}

// try {
// Statement stmtCrmUpd = crmCon.createStatement();
//
// stmtCrmUpd.addBatch("truncate table trade.sms_tmp_feild ");
// stmtCrmUpd.addBatch("INSERT INTO trade.sms_tmp_feild VALUES (0, 'membername', '%s', '会员姓名')");
// stmtCrmUpd.addBatch("INSERT INTO trade.sms_tmp_feild VALUES (1, 'cardwh', '%s', '卡号末四位')");
// stmtCrmUpd.addBatch("INSERT INTO trade.sms_tmp_feild VALUES (2, 'transmerchant', '%s', '交易店')");
// stmtCrmUpd.addBatch("INSERT INTO trade.sms_tmp_feild VALUES (3, 'transtype', '%s', '交易类型')");
// stmtCrmUpd.addBatch("INSERT INTO trade.sms_tmp_feild VALUES (4, 'transamount', '%.2f', '交易金额')");
// stmtCrmUpd.addBatch("INSERT INTO trade.sms_tmp_feild VALUES (5, 'cardbalance', '%.2f', '卡余额')");
// stmtCrmUpd.addBatch("INSERT INTO trade.sms_tmp_feild VALUES (6, 'merchantbrand', '%s', '交易商户集团名称')");
// stmtCrmUpd.addBatch("INSERT INTO trade.sms_tmp_feild VALUES (7, 'couponname', '%s', '券名称')");
// stmtCrmUpd.addBatch("INSERT INTO trade.sms_tmp_feild VALUES (9, 'cardno', '%s', '卡号')");
// stmtCrmUpd.addBatch("INSERT INTO trade.sms_tmp_feild VALUES (10, 'cardmerchant', '%s', '卡属商户名')");
// stmtCrmUpd.addBatch("INSERT INTO trade.sms_tmp_feild VALUES (11, 'transdate', '%tm月%te日', '交易日期')");
// stmtCrmUpd.addBatch("INSERT INTO trade.sms_tmp_feild VALUES (12, 'transtime', '%tT', '交易时间')");
//
// crmCon.setAutoCommit(false);
// //成功的话再提交保存当前最大ID号和失败日志
// stmtCrmUpd.executeBatch();
// crmCon.commit();
// crmCon.setAutoCommit(true);
//
// }catch (Exception ex) {
// System.out.println("数据库执行异常！");
// System.out.println(ex);
// try {
// crmCon.rollback();
// }catch (Exception e) {
// System.out.println("数据库回滚异常！");
// System.out.println(e);
// }
// }
//
// ResultSet rset = null;
//
// String sql = "select field_name,field_type from trade.sms_tmp_feild";
// Map<String,String> m = new HashMap<String,String>();
// try {
// Statement stmtCrm = crmCon.createStatement();
// rset = stmtCrm.executeQuery(sql);
//
// if (rset!=null){
// while (rset.next()){
// m.put(rset.getString("field_name"), rset.getString("field_type"));
// }
// rset.close();
// }
// rset = null;
// stmtCrm.close();
// stmtCrm = null;
// }catch (Exception ex) {
// System.out.println("数据库执行异常！");
// System.out.println(ex);
// }
//
//
// String strSql = "SELECT id,replace(replace(replace(replace(replace(replace(message_template,'tm月%te日',''),'d',''),'.2f',''),'tF',''),'tT',''),'s','') as message_template," +
// "template_feilds FROM trade.message_template";
//
// try {
// Statement stmtCrm = crmCon.createStatement();
// Statement stmtCrmUpd = crmCon.createStatement();
// rset = stmtCrm.executeQuery(strSql);
//
// if (rset!=null){
// while (rset.next()){
// if (rset.getString("template_feilds")!=null&&rset.getString("message_template")!=null){
// String[] aryFeild = rset.getString("template_feilds").split(",");
// String[] aryCon = rset.getString("message_template").split("%");
// String tid = rset.getString("id");
//
// if (aryFeild!=null&&aryFeild.length>0&&aryCon!=null&&aryCon.length>0){
// StringBuilder strB = new StringBuilder();
// StringBuilder strF = new StringBuilder();
// StringBuilder bSql = new StringBuilder();
// strB.append(aryCon[0]);
// for (int i=1;i<aryCon.length;i++){
// String strFormatCon = m.get(aryFeild[i-1]);
// if (strFormatCon.indexOf("%", 1)>0){
// strF.append(aryFeild[i-1]+",");
// }
// strF.append(aryFeild[i-1]+",");
// strB.append(strFormatCon);
// strB.append(aryCon[i]);
// }
//
// if (strF.lastIndexOf(",")==strF.length()-1){
// strF.delete(strF.length()-1, strF.length());
// }
// System.out.println("原模板内容："+rset.getString("message_template"));
// System.out.println("新摸版内容："+strB.toString());
// System.out.println("原模板字段："+rset.getString("template_feilds"));
// System.out.println("新模板字段："+strF.toString());
//
// bSql.append("update trade.message_template set message_template='"+strB.toString()+"',template_feilds='"+strF.toString()+"' where id="+tid);
//
// System.out.println("修改模板Sql："+strF.toString());
//
// stmtCrmUpd.addBatch(bSql.toString());
// }
// }
// }
// rset.close();
// }
// rset = null;
// stmtCrm.close();
// stmtCrm = null;
//
// crmCon.setAutoCommit(false);
// stmtCrmUpd.executeBatch();
// crmCon.commit();
// crmCon.setAutoCommit(true);
//
// stmtCrmUpd.close();
// stmtCrmUpd = null;
// }catch (Exception ex) {
// System.out.println("数据库执行异常！");
// System.out.println(ex);
// try {
// crmCon.rollback();
// }catch (Exception e) {
// System.out.println("数据库回滚异常！");
// System.out.println(e);
// }
// }

cp.closeConn(crmCon);
}
}

Answer 2

package newtest;
import java.sql.*;
public class Sql_Test {
static Connection con;
static Statement sql;
static ResultSet rs;

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
String url="jdbc:odbc:test";
String user="username";
String password="password";
try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");//加载驱动器
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try{
con=DriverManager.getConnection(url,user,password);//创建Connection对象，Connection对象负责和数据源进行连接
sql=con.createStatement();//创建Statement对象，Statement对象负责执行sql语句,暂解
rs=sql.executeQuery("select * from Students");
System.out.print("学号\t"+"姓名\t"+"出生日期\t\t"+"性别\t"+"专业\n");
while(rs.next()){
System.out.print(rs.getString(1)+"\t"+rs.getString(2)+"\t"+rs.getDate(3)
+"\t"+rs.getString(4)+"\t"+rs.getString(5)+"\n");
// System.out.println(rs.getInt(1)+"\t"+rs.getString(2)+"\t"+rs.getDate(3)+
// "\t"+rs.getString(4)+"\t"+rs.getInt(5));
}
}catch(SQLException se){}

}

}

Answer 3

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DButil {
private static String username="scott";
private static String password="tiger";
private static String url="jdbc:oracle:thin:@192.168.1.100:1521:ORCL";
static{
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

public static Connection getConn(){
Connection conn=null;
try {
System.out.println("--------------");
conn=DriverManager.getConnection(url, username, password);

} catch (SQLException e) {
// TODO Auto-generated catch block

e.printStackTrace();
System.out.println("没有获得连接");
}
return conn;
}

public static void free(Connection conn,PreparedStatement ps,ResultSet rs){
try{
if(rs!=null) rs.close();
if(ps!=null) ps.close();
if(conn!=null) conn.close();
}catch(Exception e){
e.printStackTrace();
}
}

public static void main(String[] args) throws SQLException {
DButil db=new DButil();
Connection conn=DriverManager.getConnection(url, username, password);
if(conn!=null){

System.out.println("连接成功");
}
System.out.println(db.getConn().getClass().getName());
}
}

追问

麻烦我要的是连接SQLserver的不是oracle的

追答

不是一样的吗