如何解决这个问题，它说'queryForObject(java.lang.String, java.lang.Object[], java.lang.Class<T>)' 已弃用答案

【问题标题】：How do I fix this problem it say's 'queryForObject(java.lang.String, java.lang.Object[], java.lang.Class<T>)' is deprecated如何解决这个问题，它说'queryForObject(java.lang.String, java.lang.Object[], java.lang.Class<T>)' 已弃用
【发布时间】：2021-12-15 10:47:15
【问题描述】：

我不知道如何解决这个问题，因为我上周四才开始做 Spring Boot 项目。不幸的是，今天是我项目的最后期限，坦率地说，我现在很恐慌：/

这是我的示例问题代码：

@Override
public Integer getCountByEmail(String email) {
    return jdbcTemplate.queryForObject(SQL_COUNT_BY_EMAIL, new Object[]{email}, Integer.class);
}

@Override
public User findById(Integer userId) {
    return null;
}

Java类的整体代码如下：

package com.example.Spring.boot.Repositories;

import com.example.Spring.boot.Entity.User;
import com.example.Spring.boot.Exceptions.EtAuthException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.support.GeneratedKeyHolder;
import org.springframework.jdbc.support.KeyHolder;
import org.springframework.stereotype.Repository;

import java.sql.PreparedStatement;
import java.sql.Statement;

@Repository
public class UserRepositoryImpl implements UserRepository {

private static final String SQL_CREATE = "INSERT INTO SB_USERS(USER_ID, 
FIRST_NAME, LAST_NAME, EMAIL," +`"PASSWORD) VALUES(NEXTVAL('SB_USERS_SEQ'), ?, ?, ?, ?)";`
private static final String SQL_COUNT_BY_EMAIL = "SELECT COUNT(*) FROM SB_USERS WHERE EMAIL = ?";
private static final String ID = "SELECT USER_ID, FIRST_NAME, LAST_NAME, EMAIL, PASSWORD " +`"FROM SB_USERS WHERE USER_ID = ?";`
       
@Autowired
JdbcTemplate jdbcTemplate;

@Override
public Integer create(String firstName, String lastName, String email, String password) throws EtAuthException {
    try {
        KeyHolder keyHolder = new GeneratedKeyHolder();
        jdbcTemplate.update(connection -> {
            PreparedStatement ps = connection.prepareStatement(SQL_CREATE, Statement.RETURN_GENERATED_KEYS);
            ps.setString(1, firstName);
            ps.setString(2, lastName);
            ps.setString(3, email);
            ps.setString(4, password);
            return ps;
        }, keyHolder);
        return (Integer) keyHolder.getKeys().get("USER_ID");
    }catch (Exception e) {
        throw new EtAuthException("Invalid details. Failed to create account");
    }
}

@Override
public User findByEmailAndPassword(String email, String password) throws EtAuthException {
    return null;
}

@Override
public Integer getCountByEmail(String email) {
    return jdbcTemplate.queryForObject(SQL_COUNT_BY_EMAIL, new Object[]{email}, Integer.class);
}

@Override
public User findById(Integer userId) {
    return null;
}

}

【问题讨论】：

标签： java-11 jdbctemplate spring-boot-maven-plugin implements postgresql-14

【解决方案1】：

以下方法已被弃用，不得使用：

public <T> T queryForObject(String sql, @Nullable Object[] args, Class<T> requiredType)

请改用以下等效方法：

 <T> T queryForObject(String sql, Class<T> requiredType, @Nullable Object... args)

例子：

return jdbcTemplate.queryForObject(SQL_COUNT_BY_EMAIL, Integer.class, email);

【讨论】：