本文主要是介绍Mysql - Upsert功能实现，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
在看到了
mongoTemplate的操作之后，觉得这种东西是很符合我们程序员世界的操作的，但是看到mysql的jdbc之后，瞬间一百万个小泥马从头飘过，所以就想自己实现一个mysql版本的upsert功能，有set与increase,decrease。
实现操作
参考mongoTemplate,创建一个update.java与query.java类,方便两款db之间转换
import java.util.HashMap;
import java.util.Map;public class Update {private Map<String, Object> sets = new HashMap<>();private Map<String, Object> incs = new HashMap<>();//省略get set操作
}public class Query {private Map<String,Object> values = new HashMap<>();public Query equals(String name,Object value){values.put(name,value);return this;}//省略get set操作
}
只依赖一个包
compile group: 'mysql', name: 'mysql-connector-java', version: '5.1.39'
MysqlClient 客户端工具
代码非常精简,大家可以根据自己的喜好添加功能
import java.sql.*;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.util.*;
import java.util.stream.Collectors;public class MysqlClient {private Connection connection;private String jdbcUrl;private String driver = "com.mysql.jdbc.Driver";public MysqlClient(String jdbcUrl) {this.jdbcUrl = jdbcUrl;this.init();}public void init() {try {if (connection == null || connection.isClosed()) {String[] split = jdbcUrl.split("\\|");Class.forName(driver);connection = DriverManager.getConnection(split[0], split[1], split[2]);}} catch (SQLException e) {e.printStackTrace();} catch (ClassNotFoundException e) {e.printStackTrace();}}public void upsert(String table, Query query, Update update) {List<String> names = new ArrayList<>();List<Object> params = new ArrayList<>();names.addAll(query.getValues().keySet().stream().map(item -> String.format("`%s`", item)).collect(Collectors.toList()));names.addAll(update.getSets().keySet().stream().map(item -> String.format("`%s`", item)).collect(Collectors.toList()));names.addAll(update.getIncs().keySet().stream().map(item -> String.format("`%s`", item)).collect(Collectors.toList()));List<String> values = new ArrayList<>();values.addAll(query.getValues().values().stream().map(item -> " ? ").collect(Collectors.toList()));params.addAll(query.getValues().values());values.addAll(update.getSets().values().stream().map(item -> " ? ").collect(Collectors.toList()));params.addAll(update.getSets().values());values.addAll(update.getIncs().values().stream().map(item -> " ? ").collect(Collectors.toList()));params.addAll(update.getIncs().values());List<String> updates = new ArrayList<>();update.getSets().forEach((key, value) -> {updates.add(String.format(" `%s` = ? ", key));params.add(value);});update.getIncs().forEach((key, value) -> {updates.add(String.format(" `%s` = `%s` + %s", key, key, value));});String sql = String.format("INSERT INTO `%s` (%s) VALUES(%s) ON DUPLICATE KEY UPDATE %s",table,String.join(",", names),String.join(",", values),String.join(",", updates));this.execute(sql, params.toArray());}private void fillStatement(PreparedStatement statement, Object... params) throws SQLException {for (int i = 1, len = params.length; i <= len; i++) {Object value = params[i - 1];if (value instanceof String) {statement.setString(i, value.toString());} else if (value instanceof Integer) {statement.setInt(i, Integer.parseInt(value.toString()));} else if (value instanceof Boolean) {statement.setBoolean(i, Boolean.parseBoolean(value.toString()));} else if (value instanceof LocalDate || value instanceof LocalDateTime) {statement.setString(i, value.toString());} else if (value instanceof Long) {statement.setLong(i, Long.parseLong(value.toString()));} else if (value instanceof Double) {statement.setDouble(i, Double.parseDouble(value.toString()));} else if (value instanceof Float) {statement.setDouble(i, Float.parseFloat(value.toString()));} else {statement.setString(i, value.toString());}}}public void execute(String sql, Object... params) {try {PreparedStatement statement = connection.prepareStatement(sql);this.fillStatement(statement, params);statement.executeUpdate();} catch (SQLException e) {e.printStackTrace();}}
}
使用方法
@Test
public void testUpsert(){MysqlClient mysqlClient = new MysqlClient("jdbc:mysql://demo.com:3306/db?useUnicode=true&useSSL=false&autoReconnect=true|root|password");Update update = new Update();update.set("count", 0);update.inc("active", 1);Query query = new Query();query.equals("name", "abc");mysqlClient.upsert("test", query, update);//含义：对相同行的`name`='abc',对其字段`count`重置为0,`active`新增1
}
解析
生成的sql语句会像这样子
INSERT INTO `test` (`name`,`count`,`active`,`value`) VALUES( ? , ? , ? , ? ) ON DUPLICATE KEY UPDATE `count` = ? , `active` = `active` + 1, `value` = `value` - 1
并且使用了占位符号,增加特殊符号的解析容错能力
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