【Java】jdbc数据库操作简单工具包

　　dbUtils.java(本人使用的是mysql-connector-java 8.0.22)

package pers.dbutils;

import lombok.Data;

import java.io.IOException;
import java.io.InputStream;
import java.sql.*;
import java.util.*;
import java.util.stream.Collectors;

/**
 * TODO     jdbc常用操作工具类
 *
 * @author netyts@163.com
 * @date 2020/11/6 15:24
 */

@Data
public class DbUtils {
    private String driver = "com.mysql.cj.jdbc.Driver";
    private String url = "jdbc:mysql://localhost:3306/db?serverTimezone=PRC&useUnicode=true&characterEncoding=utf8";
    private String user = "root";
    private String password = "";
    private Connection conn = null;
    private int currentPage = 1;   //当前页
    private int pageCount = 0; //总页数
    private int pageSize = 10;  //每一页记录的数据量
    private int recordCount = 0;    //总数据量

    public DbUtils() {
        try {
            this.conn = DriverManager.getConnection(url, user, password);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }

    public DbUtils(String driver, String host, String port, String dbName, String user, String password) {
        this.driver = driver;
        this.url = "jdbc:mysql://" + host + ":" + port + "/" + dbName + "?serverTimezone=PRC&useUnicode=true&characterEncoding=utf8";
        this.user = user;
        this.password = password;
        try {
            this.conn = DriverManager.getConnection(this.url, this.user, this.password);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }

    //利用db.properties配置文件连接数据库
    public DbUtils(boolean flag) {
        InputStream is = DbUtils.class.getClassLoader().getResourceAsStream("db.properties");
        Properties prop = new Properties();
        try {
            prop.load(is);
            driver = prop.getProperty("db.driver", "com.mysql.cj.jdbc.Driver");
            url = prop.getProperty("db.url", "jdbc:mysql://localhost:3306/db?serverTimezone=PRC&useUnicode=true&characterEncoding=utf8");
            user = prop.getProperty("db.user", "root");
            password = prop.getProperty("db.password", "");
            pageSize = Integer.parseInt(prop.getProperty("db.pageSize", "10"));

            conn = DriverManager.getConnection(url, user, password);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }

    /**
     * 数据库数据语句操作（增、删、改）
     *
     * @param sql    sql语句
     * @param params    0个或多个
     * @return 对数据表产生影响的行数
     */
    public int execute(String sql, Object... params) {
        int row = 0;
        try {
            PreparedStatement ps = conn.prepareStatement(sql);
            int index = 1;
            for (Object p : params) {
                ps.setObject(index++, p);
            }
            row = ps.executeUpdate();
            ps.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return row;
    }

    /**
     * 数据插入
     *
     * @param tableName 表名
     * @param values    Map(key,values)键值对
     * @return  对数据表产生影响的行数
     */
    public int insert(String tableName, Map<String, Object> values) {
        int row = 0;
        Set<String> set = values.keySet();

        String fn = set.toString().replace(" ", "");
        fn = fn.substring(1, fn.length() - 1);

        String fv = set.stream().map(m -> "?").collect(Collectors.toList()).toString().replace(" ", "");
        fv = fv.substring(1, fv.length() - 1);

        String sql = String.format("insert into %s(%s) values(%s)", tableName, fn, fv);
        try {
            PreparedStatement ps = conn.prepareStatement(sql);
            int index = 1;
            for (String k : set) {
                ps.setObject(index++, values.get(k));
            }
            row = ps.executeUpdate();
            ps.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return row;
    }

    /**
     * 数据插入
     *
     * @param tableName   表名
     * @param fieldName 字段名（1个或多个）
     * @param fieldValues 数据信息（和字段名顺序保持一致）
     * @return  对数据表产生影响的行数
     */
    public int insert(String tableName, String fieldName, Object[] fieldValues) {
        int row = 0;
        String fv = Arrays.stream(fieldValues).map(m -> "?").collect(Collectors.toList()).toString().replace(" ", "");
        fv = fv.substring(1, fv.length() - 1);
        String sql = String.format("insert into %s(%s) values(%s)", tableName, fieldName, fv);
        try {
            PreparedStatement ps = conn.prepareStatement(sql);
            for (int i = 0; i < fieldValues.length; i++) {
                ps.setObject(i + 1, fieldValues[i]);
            }
            row = ps.executeUpdate();
            ps.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return row;
    }

    /**
     *  根据主键删除数据
     * @param tableName 表名
     * @param PKValues    主键值（1个或多个）
     * @return  对数据表产生影响的行数
     */
    public int deleteByPK(String tableName, Object... PKValues){
        int row = 0;
        Set<Object> set = new HashSet<>();
        for(Object o : PKValues){
            set.add(o);
        }
        StringBuilder sql = new StringBuilder("delete from "+tableName+" where "+getPK(tableName)+" in(");
        int index = 1;
        for(Object o : set){
            sql.append(o);
            if(index++ < set.size()) sql.append(",");
        }
        sql.append(")");
        try {
            PreparedStatement ps = conn.prepareStatement(sql.toString());
            row = ps.executeUpdate();
            ps.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return row;
    }

    /**
     *  根据主键修改数据
     * @param tableName 表名
     * @param fieldName 字段名（1个或多个）
     * @param updateValues  修改后的值
     * @param PKValues  主键值（1个或多个）
     * @return  对数据表产生影响的行数
     */
    public int updateByPK(String tableName, String fieldName, Object updateValues, Object... PKValues){
        int row = 0;
        Set<Object> set = new HashSet<>();
        for(Object o : PKValues){
            set.add(o);
        }
        StringBuilder sql = new StringBuilder("update "+tableName+" set "+fieldName+"="+updateValues+" where "+getPK(tableName)+" in(");
        int index = 1;
        for(Object o : PKValues){
            sql.append(o);
            if(index++ < set.size()) sql.append(",");
        }
        sql.append(")");
        try {
            PreparedStatement ps = conn.prepareStatement(sql.toString());
            row = ps.executeUpdate();
            ps.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return row;
    }

    /**
     * 对某一列（某几个）的值全部增加或减少相同的值
     *
     * @param tableName 表名
     * @param fieldName 字段名（1个或多个）
     * @param values    要增加或减少的值
     * @param condition     条件
     * @return  对数据表产生影响的行数
     */
    public int updateInc(String tableName, String fieldName, Object values, String condition) {
        int row = 0;
        String sql = String.format("update %s set %2$s=%s+%d %s", tableName, fieldName, values, condition);
        try {
            PreparedStatement ps = conn.prepareStatement(sql);
            row = ps.executeUpdate();
            ps.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return row;
    }

    /**
     *  获取主键的字段名
     * @param tableName 表名
     * @return  表的主键字段名
     */
    public String getPK(String tableName) {
        String PKName = null;
        try {
            DatabaseMetaData dmd = conn.getMetaData();
            ResultSet rs = dmd.getPrimaryKeys(null, "%", tableName);
            rs.next();
            PKName = rs.getString("column_name");
            rs.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
//        //方法二
//        String sql = String.format("show index from %s", tableName);
//        try {
//            PreparedStatement ps = conn.prepareStatement(sql);
//            ResultSet rs = ps.executeQuery();
//            rs.next();
//            PKName = rs.getString("column_name");
//            rs.close();
//            ps.close();
//        } catch (SQLException throwables) {
//            throwables.printStackTrace();
//        }
        return PKName;
    }

    /**
     *  查询操作
     * @param sql   sql语句
     * @param params    0个或多个
     * @return  list集合
     */
    public List<Map<String, Object>> select(String sql, Object... params) {
        List<Map<String, Object>> list = new LinkedList<>();
        try {
            PreparedStatement ps = conn.prepareStatement(sql);
            int index = 1;
            for (Object o : params) {
                ps.setObject(index++, o);
            }
            ResultSet rs = ps.executeQuery();
            ResultSetMetaData rsm = rs.getMetaData();
            Map<String, Object> m;
            while (rs.next()) {
                m = new LinkedHashMap<>();
                for (int i = 1; i <= rsm.getColumnCount(); i++) {
                    m.put(rsm.getColumnLabel(i), rs.getObject(rsm.getColumnLabel(i)));
                }
                list.add(m);
            }
            rs.close();
            ps.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return list;
    }

    /**
     *  查询操作
     * @param tableName 表名
     * @param fieldName 字段名（1个或多个）
     * @param condition 条件
     * @return  list集合
     */
    public List<Map<String, Object>> select(String tableName, String fieldName, String condition) {
        String sql = String.format("select %s from %s %s", fieldName, tableName, condition);
        return select(sql);
    }

//    private int currPage = 1;   //当前页
//    private int pageCount = 0; //总页数
//    private int pageSize = 10;  //每一页的数据量
//    private int recordCount = 0;    //总数据量

    /**
     *  获取总数据数量
     * @param tableName 表名
     * @param condition 条件
     * @return  总数据量
     */
    public int getRecordCount(String tableName, String condition) {
        String sql = String.format("select count(*) from %s %s", tableName, condition);
        try {
            PreparedStatement ps = conn.prepareStatement(sql);
            ResultSet rs = ps.executeQuery();
            rs.next();
            recordCount = rs.getInt(1);
            rs.close();
            ps.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return recordCount;
    }

    /**
     *  获取总页数
     * @param tableName 表名
     * @param pageSize  每一页记录的数据量
     * @param condition 条件
     * @return  总页数
     */
    public int getPageCount(String tableName, int pageSize, String condition) {
        recordCount = getRecordCount(tableName, condition);
        if (recordCount % pageSize == 0) {
            pageCount = recordCount / pageSize;
        } else {
            pageCount = recordCount / pageSize + 1;
        }
        return pageCount;
    }

    public int getPageCount(String tableName, String where) {
        return getPageCount(tableName, pageSize, where);
    }

    /**
     *  查看某一页的数据
     * @param tableName 表名
     * @param fieldName 字段名（1个或多个）
     * @param currentPage   选择要查看的页数（当前页）
     * @param pageSize  每页记录的数据量
     * @param condition 条件
     * @return list集合
     */
    public List<Map<String, Object>> page(String tableName, String fieldName, int currentPage, int pageSize, String condition) {
        pageCount = getPageCount(tableName, pageSize, condition);
        List<Map<String, Object>> list = new LinkedList<>();
        if (currentPage <= pageCount) {
            int cp = pageSize * (currentPage - 1);
            String sql = String.format("select %s from %s limit %d,%d %s", fieldName, tableName, cp, pageSize, condition);
            System.out.println(sql);
            try {
                PreparedStatement ps = conn.prepareStatement(sql);
                ResultSet rs = ps.executeQuery();
                ResultSetMetaData rsm = rs.getMetaData();
                Map<String, Object> m;
                while (rs.next()) {
                     m = new LinkedHashMap<>();
                    for (int i = 1; i <= rsm.getColumnCount(); i++) {
                        m.put(rsm.getColumnLabel(i), rs.getObject(rsm.getColumnLabel(i)));
                    }
                    list.add(m);
                }
                rs.close();
                ps.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        } else {
            Map<String, Object> m = new HashMap<>();
            m.put("error", "页码输入有误！");
            list.add(m);
        }
        return list;
    }

    /**
     *  查看某一页的数据
     * @param tableName 表名
     * @param fieldName 字段名（1个或多个）
     * @param currentPage    选择要查看的页数（当前页）
     * @return  list集合
     */
    public List<Map<String, Object>> page(String tableName, String fieldName, int currentPage){
        return page(tableName, fieldName, currentPage, pageSize, "");
    }

    /**
     *  导出表数据到txt文件,需要判断secure_file_priv(show variables like "secure_file_priv";)的状态，
     *  若为null，则是对mysqld的导入、导出做限制，修改my.ini文件添加或修改secure_file_priv="";
     * @param tableName 表名
     * @param fieldName 字段名（1个或多个）
     * @param file  文件路径
     */
    public void exportData(String tableName, String fieldName, String file) {
        String sql = String.format("select %s from %s into outfile '%s'", fieldName,tableName,file);
        try {
            PreparedStatement ps = conn.prepareStatement(sql);
            ResultSet rs = ps.executeQuery();
            ps.close();
            rs.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }

    /**
     *  导入表数据，数据库必须有此表的表结构
     * @param file  文件路径
     * @param tableName 表名
     */
    public void importData(String file, String tableName) {
        String sql = String.format("load data infile '%s' into table %s",file,tableName);
        try {
            PreparedStatement ps = conn.prepareStatement(sql);
            ResultSet rs = ps.executeQuery();
            ps.close();
            rs.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }

    public void close() {
        try {
            conn.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }
}

　　db.properties

db.driver = com.mysql.sj.jdbc.Driver
db.url = jdbc:mysql://localhost:3306/db?serverTimezone=PRC&useUnicode=true&characterEncoding=utf8
db.user = root
db.password =
db.pageSize = 5