Java通过xml文件方法实现JDBC代码案例

Java熬夜党
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今天和大家分享一下Java通过xml文件方法实现JDBC代码案例。

一、使用步骤

1.Maven导包

<pre class="prettyprint hljs xml" style="padding: 0.5em; font-family: Menlo, Monaco, Consolas, &quot;Courier New&quot;, monospace; color: rgb(68, 68, 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246, 246, 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;"><?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.iteheima</groupId>
    <artifactId>jdbc</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.30</version>
        </dependency>

        <dependency>
            <groupId>org.dom4j</groupId>
            <artifactId>dom4j</artifactId>
            <version>2.0.0</version>
        </dependency>
    </dependencies>
</project></pre>

2.定义xml文件

按照自己情况定义Url，Username，Password等信息

<pre class="prettyprint hljs xml" style="padding: 0.5em; font-family: Menlo, Monaco, Consolas, &quot;Courier New&quot;, monospace; color: rgb(68, 68, 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246, 246, 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;"><?xml version="1.0" encoding="utf-8" ?>
<jdbc_config>
    <mysql_config>
        <DriverClass>com.mysql.cj.jdbc.Driver</DriverClass>
        <Url>jdbc:mysql://localhost:3306/aaa</Url>
        <Username>root</Username>
        <Password>12345678</Password>
        <Sql>select * from employee</Sql>
    </mysql_config>
</jdbc_config></pre>

3.定义JDBCUtils类

<pre class="prettyprint hljs dart" style="padding: 0.5em; font-family: Menlo, Monaco, Consolas, &quot;Courier New&quot;, monospace; color: rgb(68, 68, 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246, 246, 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">package pack03;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.io.InputStream;
import java.sql.*;
import java.util.Iterator;
import java.util.Properties;

public class JDBCUtils { 

    private static String driverClass;
    private static String url;
    private static String username;
    private static String password;
    private static String sql;

    private JDBCUtils(){ }
    //封装注册驱动.这里是mysql 8.0的版本
    static { 
        try { 
            //1.加载Reader对象
            SAXReader reader = new SAXReader();
            //2.加载xml对象
            InputStream inputStream =
                    JDBCUtils.class.getClassLoader().getResourceAsStream("jdbc.xml");
            Document document = reader.read(inputStream);

            //3.获得根结点
            Element rootElement = document.getRootElement();

            //4.获得子元素
            Iterator<Element> iterator = rootElement.elementIterator();
            while (iterator.hasNext()){ 
                Element element = iterator.next();
                Iterator<Element> iterator1 = element.elementIterator();
                while (iterator1.hasNext()){ 
                    Element element1 = iterator1.next();
                    String name = element1.getName();
                    if (name.equals("DriverClass")){ 
                        driverClass = element1.getStringValue();
                    }
                    else if (name.equals("Url")){ 
                        url = element1.getStringValue();
                    }
                    else if (name.equals("Username")){ 
                        username = element1.getStringValue();
                    }
                    else if (name.equals("Password")){ 
                        password = element1.getStringValue();
                    }
                    else if (name.equals("Sql")){ 
                        sql = element1.getStringValue();
                    }
                }
            }

            Class.forName(driverClass);
        } catch (Exception e) { 
            throw new RuntimeException(e);
        }
    }
    //封装获得连接
    public static Connection getConnection(){ 
        try { 

            return DriverManager.getConnection(url, username, password);
        } catch (SQLException e) { 
            throw new RuntimeException(e);
        }
    }
    //封装获得执行sql语句的对象
    public static ResultSet getResult(Statement statement,Connection connection){ 
        try { 
            return statement.executeQuery(sql);
        } catch (SQLException e) { 
            throw new RuntimeException(e);
        }
    }
    //封装处理结果
    public static void printResult(ResultSet resultSet){ 
        try { 
            ResultSetMetaData metaData = resultSet.getMetaData();
            int columnCount = metaData.getColumnCount();

            while (resultSet.next()){ 
                for (int i = 1; i <= columnCount; i++) { 
                    Object object = resultSet.getObject(i);
                    System.out.print(object + "\t");
                }
                System.out.println();
            }
        } catch (SQLException e) { 
            throw new RuntimeException(e);
        }
    }
    //封装释放资源
    public static void closeAll(Statement statement,Connection connection){ 
        try { 
            statement.close();
            connection.close();
        } catch (SQLException e) { 
            throw new RuntimeException(e);
        }
    }

}</pre>

4.最后定义测试类

<pre class="prettyprint hljs java" style="padding: 0.5em; font-family: Menlo, Monaco, Consolas, &quot;Courier New&quot;, monospace; color: rgb(68, 68, 68); border-radius: 4px; display: block; margin: 0px 0px 1.5em; font-size: 14px; line-height: 1.5em; word-break: break-all; overflow-wrap: break-word; white-space: pre; background-color: rgb(246, 246, 246); border: none; overflow-x: auto; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">package pack03;

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

public class demo01 { 
    public static  void  main(String[] args) throws Exception { 
        //注册驱动.这里是mysql 8.0的版本
        //获得连接.
        Connection connection = JDBCUtils.getConnection();

        //获得执行sql语句的对象
        Statement statement = connection.createStatement();
        //执行sql语句，并返回结果
        ResultSet resultSet =
                JDBCUtils.getResult(statement,connection);

        //处理结果
        JDBCUtils.printResult(resultSet);

        //释放资源
        JDBCUtils.closeAll(statement,connection);
    }
}</pre>

今天通过一个小案例和大家分享了一下JDBC的另外一种通过xml的使用方法，xml比properties方法更为常见。大家根据自己实际项目情况使用即可。

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