jdbc中对mysql数据库操作的简单封装--（仅做备忘记录）

本次使用jdbc中的mysql-connector-java-5.1.47-bin.jar的连接包，下载这个jar包放在javaee项目的WEB-INF/lib目录下，再把它作为外包jar包进入到libraries中，这样就可以使用mysql的jdbc接口了。

自己封装的代码中引入了两个自己字义的Exception:
SqlSecureException.java

package com.myproweb.exception;

public class SqlSecureException extends Exception {

    /**
     * 
     */
    private static final long serialVersionUID = -185202535331616389L;

}

SqlErrorException.java

package com.myproweb.exception;

public class SqlSecureException extends Exception {

    /**
     * 
     */
    private static final long serialVersionUID = -185202535331616389L;

}

最后封装代码如下：

package com.myproweb.utils;

import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

import com.myproweb.exception.SqlErrorException;
import com.myproweb.exception.SqlSecureException;
import com.mysql.jdbc.Connection;
import com.mysql.jdbc.Statement;

public class MysqlDatabaseConnection {

    private static String mysql_username = "root";
    private static String mysql_password = "";
    private static String mysql_connection_url = "jdbc:mysql://localhost:3306/javadb";
    private static Connection mysql_connection;
    private static Boolean check_fileds_safety = true;

    static {
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

    private static Boolean validateValueString(String value_string) {
        value_string = value_string.toLowerCase();
        String validateString="'|or|and|;|-|--|+|,|like|//|/|*|%|#";
        String[] validateStrings = validateString.split("\\|");
        for (int i = 0; i < validateStrings.length; i++) {
            if (value_string.indexOf(validateStrings[i]) >= 0) {
                return false;
            }
        }
        return true;
    }
    private static String getSqlValue(Object obj) throws SqlSecureException {
        String sql_value_string = null;
        if (obj instanceof String) {
            if(check_fileds_safety){
                if(validateValueString(obj.toString().trim())) {
                    sql_value_string = "'" + obj.toString().trim() + "'";
                }else {
                    throw new SqlSecureException();
                }
            }else {
                sql_value_string = "'" + obj.toString().trim() + "'";
            }
        }

        if (obj instanceof Integer) {
            sql_value_string = ((Integer) obj).toString();
        }

        if (obj instanceof Long) {
            sql_value_string = ((Long) obj).toString();
        }

        if (obj instanceof Float) {
            sql_value_string = ((Float) obj).toString();
        }

        if (obj instanceof Double) {
            sql_value_string = ((Double) obj).toString();
        }
        return sql_value_string;
    }

    private static String getWheresSqlString(Map wheres) throws SqlErrorException, SqlSecureException {
        String where_string = "";
        for (String key : wheres.keySet()) {
            Object[] condition = wheres.get(key);
            String value_string = getSqlValue(condition[0]);
            if (condition.length == 1) {
                if (null != value_string) {
                    if ("".equals(where_string)) {
                        where_string += " " + key.trim() + "=" + value_string + " ";
                    } else {
                        where_string += "and " + key.trim() + "=" + value_string + " ";
                    }

                }
            }

            if (condition.length == 2) {
                if (!(condition[1] instanceof String)) {
                    throw new SqlErrorException("key words error[0001]!");
                }
                String judgement_condition = condition[1].toString().trim();
                if ("=".equals(judgement_condition) || "<=".equals(judgement_condition)
                        || ">=".equals(judgement_condition) || "!=".equals(judgement_condition)
                        || "<>".equals(judgement_condition)) {
                    if (null != value_string) {
                        if ("".equals(where_string)) {
                            where_string += " " + key.trim() + judgement_condition + value_string + " ";
                        } else {
                            where_string += "and " + key.trim() + judgement_condition + value_string + " ";
                        }

                    }
                } else {
                    throw new SqlErrorException("key words error[0002]!");
                }
            }

            if (condition.length == 3) {
                if (!(condition[2] instanceof String) || !(condition[1] instanceof String)) {
                    throw new SqlErrorException("key words error[0001]!");
                }
                String and_or_string = condition[2].toString().toUpperCase();
                String judgement_condition = condition[1].toString().trim();
                if (("AND".equals(and_or_string) || "OR".equals(and_or_string)) && ("=".equals(judgement_condition)
                        || "<=".equals(judgement_condition) || ">=".equals(judgement_condition)
                        || "!=".equals(judgement_condition) || "<>".equals(judgement_condition))) {
                    if (!"".equals(where_string)) {
                        where_string += and_or_string + ' ';
                    }
                    if (null != value_string) {
                        where_string += key.trim() + judgement_condition + value_string + ' ';
                    }
                } else {
                    throw new SqlErrorException("key words error[0002]!");
                }
            }
        }
        if ("".equals(where_string)) {
            throw new SqlErrorException("key words error[0003]!");
        }
        return where_string;
    }

    /**
     * 是否设置对字符值进行安全检查
     * @param is_fields_safety  true:进行安全检查  false:不进行安全检查
     */
    public static void setFieldsSecure(Boolean is_fields_safety) {
        check_fileds_safety=is_fields_safety;
    }

    // 连接数据库边接
    public static Connection getConnection() throws SQLException {
        if (null != mysql_connection) {
            close(mysql_connection);
        }
        mysql_connection = (Connection) DriverManager.getConnection(mysql_connection_url, mysql_username,
                mysql_password);
        return mysql_connection;
    }

    /**
     * 通用的删除、更新、删除函数
     * @param sql_string delete or update or insert sql语句
     * @return sql操作影响的行数
     * @throws SQLException
     */
    public static int commonDeleteOrUpdateOrInsert(String sql_string) throws SQLException {
        Connection connection = getConnection();
        Statement statement = (Statement) connection.createStatement();
        int result = statement.executeUpdate(sql_string);
        close(connection);
        close(statement);
        return result;
    }

    /**
     * 通用的查询函数
     * @param sql_string  select sql语句
     * @return 把查询的结果集放到一个二唯数组中
     * @throws SQLException
     */
    public static ArrayList> commonQuery(String sql_string) throws SQLException {
        Connection connection = getConnection();
        Statement statement = (Statement) connection.createStatement();
        ResultSet resultSet = statement.executeQuery(sql_string);
        ArrayList> arraylist = new ArrayList>();
        int column_count =resultSet.getMetaData().getColumnCount();
        while(resultSet.next()) {
            ArrayList