DBUtils工具类：
package com.example.demo;
import java.lang.reflect.Field;
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.HashMap;
import java.util.List;
import java.util.Map;
public class DBUtils {
private static String USERNAME = "root";
// 定义数据库的密码
private static String PASSWORD = "root";
// 定义数据库的驱动信息
private static String DRIVER = "com.mysql.jdbc.Driver";
// 定义访问数据库的地址
private static String URL = "jdbc:mysql://localhost:3306/demo";
private static DBUtils per = null;
// 定义数据库的链接
private Connection con = null;
// 定义sql语句的执行对象
private PreparedStatement pstmt = null;
// 定义查询返回的结果集合
private ResultSet resultSet = null;
private DBUtils() {
}
/**
* 单例模式，获得工具类的一个对象
*
* @return
*/
public static DBUtils getInstance() {
if (per == null) {
per = new DBUtils();
per.registeredDriver();
}
return per;
}
private void registeredDriver() {
// TODO Auto-generated method stub
try {
Class.forName(DRIVER);
System.out.println("注册驱动成功！");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* 获得数据库的连接
*
* @return
*/
public Connection getConnection() {
try {
con = DriverManager.getConnection(URL, USERNAME, PASSWORD);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//System.out.println("连接数据库成功!!");
return con;
}
/**
* 完成对数据库的表的添加删除和修改的操作
*
* @param sql
* @param params
* @return
* @throws SQLException
*/
public boolean executeUpdate(String sql, List<Object> params) throws SQLException {
boolean flag = false;
int result = -1; // 表示当用户执行添加删除和修改的时候所影响数据库的行数
pstmt = con.prepareStatement(sql);
if (params != null && !params.isEmpty()) {
int index = 1;
for (int i = 0; i < params.size(); i++) {
pstmt.setObject(index++, i);
}
}
result = pstmt.executeUpdate();
flag = result > 0 ? true : false;
return flag;
}
/**
* 从数据库中查询数据
*
* @param sql
* @param params
* @return
* @throws SQLException
*/
public List<Map<String, Object>> executeQuery(String sql, List<Object> params) throws SQLException {
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
int index = 1;
pstmt = con.prepareStatement(sql);
if (params != null && !params.isEmpty()) {
for (int i = 0; i < params.size(); i++) {
pstmt.setObject(index++, params.get(i));
}
}
resultSet = pstmt.executeQuery();
ResultSetMetaData metaData = resultSet.getMetaData();
int cols_len = metaData.getColumnCount();
while (resultSet.next()) {
Map<String, Object> map = new HashMap<String, Object>();
for (int i = 0; i < cols_len; i++) {
String cols_name = metaData.getColumnName(i + 1);
Object cols_value = resultSet.getObject(cols_name);
if (cols_value == null) {
cols_value = "";
}
map.put(cols_name, cols_value);
}
list.add(map);
}
return list;
}
/**
* jdbc的封装可以用反射机制来封装,把从数据库中获取的数据封装到一个类的对象里
*
* @param sql
* @param params
* @param cls
* @return
* @throws Exception
*/
public <T> List<T> executeQueryByRef(String sql, List<Object> params, Class<T> cls) throws Exception {
List<T> list = new ArrayList<T>();
int index = 1;
pstmt = con.prepareStatement(sql);
if (params != null && !params.isEmpty()) {
for (int i = 0; i < params.size(); i++) {
pstmt.setObject(index++, params.get(i));
}
}
resultSet = pstmt.executeQuery();
ResultSetMetaData metaData = resultSet.getMetaData();
int cols_len = metaData.getColumnCount();
while (resultSet.next()) {
T resultObject = cls.newInstance(); // 通过反射机制创建实例
for (int i = 0; i < cols_len; i++) {
String cols_name = metaData.getColumnName(i + 1);
Object cols_value = resultSet.getObject(cols_name);
if (cols_value == null) {
cols_value = "";
}
Field field = cls.getDeclaredField(cols_name);
field.setAccessible(true); // 打开javabean的访问private权限
field.set(resultObject, cols_value);
}
list.add(resultObject);
}
return list;
}
public void closeDB() {
if (resultSet != null) {
try {
resultSet.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (pstmt != null) {
try {
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if (con != null) {
try {
con.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
运行测试：
package com.example.demo;
import java.io.PrintWriter;
import java.util.List;
import java.util.Random;
import com.avic.user.entity.User;
public class Test {
public static void main(String[] args) throws Exception {
PrintWriter p1 = new PrintWriter("e://demo//2018822//us_user.txt");
PrintWriter p2 = new PrintWriter("e://demo//2018822//us_passwrd.txt");
PrintWriter p3 = new PrintWriter("e://demo//2018822//us_account.txt");
PrintWriter p4 = new PrintWriter("e://demo//2018822//us_user_detail.txt");
DBUtils regionUtils = DBUtils.getInstance();
regionUtils.getConnection();
String[] mobiles = { "177777777777", "18888888888", "19999999999" };
for (int i = 0; i < mobiles.length; i++) {
// 插入user
StringBuffer userbuf = new StringBuffer();
userbuf.append("INSERT INTO `us_user` VALUES (");
userbuf.append("null").append(",");
userbuf.append(mobiles[i]).append(",");
userbuf.append("null").append(",'");
userbuf.append(createDefulatUserName()).append("',");
userbuf.append("now()").append(",");
userbuf.append("1").append(",");
userbuf.append("0").append(",");
userbuf.append("0").append(",");
userbuf.append("0").append(",");
userbuf.append("0").append(",");
userbuf.append("null").append(",");
userbuf.append("0").append(",");
userbuf.append("null").append(",");
userbuf.append("null").append(",");
userbuf.append("null").append(");");
regionUtils.executeUpdate(userbuf.toString(), null);
System.out.println(userbuf.toString());
p1.write(userbuf.toString());
p1.write("\r\n");
}
// 插入密码表
for (int i = 0; i < mobiles.length; i++) {
String sql2 = "INSERT INTO `us_password` VALUES (null,(SELECT u.user_id from us_user u where u.mobile='"
+ mobiles[i] + "'), '0', '" + mobiles[i] + "', '123456', null);";
regionUtils.executeUpdate(sql2.toString(), null);
String sql5 = "INSERT INTO `us_password` VALUES (null,(SELECT u.user_id from us_user u where u.mobile='"
+ mobiles[i] + "'), '0', (SELECT u.user_name from us_user u where u.mobile='" + mobiles[i]
+ "'), '123456', null);";
regionUtils.executeUpdate(sql5.toString(), null);
System.out.println(sql5.toString());
p2.write(sql2);
p2.write("\r\n");
String sql3 = "INSERT INTO `us_account` VALUES ((SELECT u.user_id from us_user u where u.mobile='"
+ mobiles[i] + "'),0.01,0.00,0,0,0.00);";
regionUtils.executeUpdate(sql3.toString(), null);
System.out.println(sql3.toString());
p3.write(sql3);
p3.write("\r\n");
String sql4 = "INSERT INTO `us_user_detail` VALUES ((SELECT u.user_id from us_user u where u.mobile='"
+ mobiles[i]
+ "'),0,null,null,0,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null,null);";
regionUtils.executeUpdate(sql4.toString(), null);
System.out.println(sql4);
p4.write(sql4);
p4.write("\r\n");
}
p1.flush();
p1.close();
p2.flush();
p2.close();
p3.flush();
p3.close();
p4.flush();
p4.close();
}
private static String createDefulatUserName() {
String userName = null;
try {
DBUtils regionUtils = DBUtils.getInstance();
regionUtils.getConnection();
String code = "123456789ABCDEFGHIJKLMNOPQSTUVWXYZ";
StringBuffer checkCode = new StringBuffer();
userName = "";
Random ran = new Random();
for (int i = 0; i < 5; i++) {
checkCode.append(code.charAt(ran.nextInt(code.length())));
}
userName = "RR" + checkCode.toString();
String sql = "select * from us_user where user_name='" + userName + "'";
List<User> users = regionUtils.executeQueryByRef(sql, null, User.class);
if (users.size() > 0) {
userName = createDefulatUserName();
return userName;
}
} catch (Exception e) {
e.printStackTrace();
}
return userName;
}
}