Java原生操作数据库（不使用框架）

Posted 2020-09-07

1.引入数据库驱动的jar包 以通过maven引入mysql driver为例

　　1.1 到http://mvnrepository.com 搜索 mysql

　　1.2 复制所需maven配置文件到工程的 pom.xml

<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>6.0.6</version>
</dependency>

 

2.创建数据库连接类DBUtil.java用以连接与关闭数据库

//文件名：DBUtil.java

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DBUtil {

    static String user = "root";
    static String password = "root";
    static String url = "jdbc:mysql://localhost【数据库地址】:3306【端口】/【数据库名称】?serverTimezone=UTC";

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

    public static Connection getConnection() {
        Connection conn = null;
        try {
            conn = DriverManager.getConnection(url, user, password);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return conn;
    }

    public static void closeJDBC(ResultSet rs, Statement stmt, Connection conn) {
        if (rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (stmt != null) {
            try {
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if (conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

 

3.在java代码中对表进行操作

3.1 查，删，改类似

//查找table表重的 id和name
String sql = "select id,name from table";
Connection conn = DBUtil.getConnection();
PreparedStatement pstmt = null;
try {
      conn.setAutoCommit(false);
      pstmt = conn.prepareStatement(sql);
       ResultSet rs = pstmt.executeQuery();
       json = ResultSetToJson.ResultSetToJsonArray(rs);
     }catch (SQLException e){
     try {
           conn.rollback();
     }catch (SQLException e1){
           e1.printStackTrace();
     }
}finally {
    DBUtil.closeJDBC(null, pstmt, conn);
}
     return json;

3.1 增

int basicinfoID = 0;
String sql = "INSERT INTO tb_resume_basicinfo("
　　　　+ "basicinfo_id, realname, gender, birthday, current_loc, "
　　　　+ "resident_loc, telephone, email, job_intension, job_experience, head_shot,applicant_id) "
　　　　+"VALUES(SEQ_ITOFFER_RESUMEBASICINFO.NEXTVAL,?,?,?,?,?,?,?,?,?,?,?)";
Connection conn = DBUtil.getConnection();
PreparedStatement pstmt = null;
        try {
            // 关闭自动提交
            conn.setAutoCommit(false);
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, basicinfo.getRealName());
            pstmt.setString(2, basicinfo.getGender());
            pstmt.setTimestamp(3, basicinfo.getBirthday() == null ? null
                    : new Timestamp(basicinfo.getBirthday().getTime()));
            pstmt.setString(4, basicinfo.getCurrentLoc());
            pstmt.setString(5, basicinfo.getResidentLoc());
            pstmt.setString(6, basicinfo.getTelephone());
            pstmt.setString(7, basicinfo.getEmail());
            pstmt.setString(8, basicinfo.getJobIntension());
            pstmt.setString(9, basicinfo.getJobExperience());
            pstmt.setString(10, basicinfo.getHeadShot());
            pstmt.setInt(11, applicantID);
            pstmt.executeUpdate();
} catch (SQLException e) {
            try {
                // 事务回滚
                conn.rollback();
            } catch (SQLException e1) {
                e1.printStackTrace();
            }
            e.printStackTrace();
        } finally {
            DBUtil.closeJDBC(null, pstmt, conn);
        }