Java操作DB2 XML数据实践
 
自学了90分钟的DB2 XQuery,还不很熟悉,就要在项目中用了,心里很不踏实,还是先跑个CRUD的Demo看看,以免走弯路。
 
代码很粗糙,主要目的是看看JDBC是否能很好的执行这种新SQL,呵呵。
 
另外,在此之前,看到Oracle老大已经开始实现一个操作XML数据的规范,目前还没有正式出台,希望Sun能尽快跟进,将标准的API接口定出来,以支持广大的Java社区。项目有期限,我们也没时间等Sun给我们做好任何东西,自己动手实现吧。
 
下面是我做的一个Demo,希望能给正在研究这一块的朋友一点参考,XQuery SQL代码参考了DB2官方文档。
 
一、实现一个简单的数据库工具
import java.sql.*;

/**
* 简单的数据连接工具
* File: DBUtils.java
* User: leizhimin
* Date: 2008-3-18 15:19:12
*/

public class DBUtils {
    public static final String url = "jdbc:db2://192.168.3.143:50000/lavasoft";
    public static final String username = "lavasoft";
    public static final String password = "lavasoftdb2";
    public static final String driverClassName = "com.ibm.db2.jcc.DB2Driver";

    /**
     * 获取数据库连接Connection
     *
     * @return 数据库连接Connection
     */

    public static Connection makeConnection() {
        Connection conn = null;
        try {
            Class.forName(driverClassName);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        try {
            conn = DriverManager.getConnection(url, username, password);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return conn;
    }

    public static void main(String args[]) {
        testConnection();
    }

    /**
     * 测试连接方法
     */

    public static void testConnection() {
        Connection conn = makeConnection();
        try {
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery("SELECT * FROM DM_HYML");
            while (rs.next()) {
                String s1 = rs.getString(1);
                String s2 = rs.getString(2);
                System.out.println(s1 + s2);
            }
            rs.close();
            stmt.close();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}
 
二、写一个简单的测试类执行各种XQuery SQL
 
import com.topsoft.icib.common.utils.DBUtils;

import java.sql.*;
import java.io.ByteArrayInputStream;
import java.io.InputStream;
import java.io.IOException;

/**
* DB2 XML数据操作测试
* File: TestXMLDAO.java
* User: leizhimin
* Date: 2008-3-18 16:33:51
*/

public class TestDB2XML {

    /**
     * 预删除表Customer
     *
     * @throws SQLException
     */

    public static void testDropXMLTable() throws SQLException {
        String drop_sql = "DROP TABLE Customer";
        Connection conn = DBUtils.makeConnection();
        Statement stmt = conn.createStatement();
        stmt.executeUpdate(drop_sql);
        stmt.close();
        conn.close();
    }

    /**
     * 创建表
     *
     * @throws SQLException
     */

    public static void testCreateXMLTable() throws SQLException {
        String ct_sql = "CREATE TABLE Customer (Cid BIGINT NOT NULL PRIMARY KEY, Info XML)";
        Connection conn = DBUtils.makeConnection();
        Statement stmt = conn.createStatement();
        stmt.executeUpdate(ct_sql);
        stmt.close();
        conn.close();
    }

    /**
     * 插入数据
     *
     * @throws SQLException
     * @throws IOException
     */

    public static void testInsertXMLTable() throws SQLException, IOException {
        String xml = "<customerinfo xmlns=\"http://posample.org\" Cid=\"1000\">\n" +
                "<name>Robert Shoemaker</name>\n" +
                "<addr country=\"Canada\">\n" +
                "<street>1596 Baseline</street>\n" +
                "<city>zhengzhou</city>\n" +
                "<prov-state>Ontario</prov-state>\n" +
                "<pcode-zip>N8X 7F8</pcode-zip>\n" +
                "</addr>\n" +
                "<phone type=\"work\">905-555-2937</phone>\n" +
                "</customerinfo>";
        String ins_sql = "INSERT INTO CUSTOMER (CID, INFO) VALUES (1000, ?)";
        Connection conn = DBUtils.makeConnection();
        conn.setAutoCommit(false);
        PreparedStatement pstmt = conn.prepareStatement(ins_sql);
        byte[] b = xml.getBytes();
        InputStream ins = new ByteArrayInputStream(b);
        pstmt.setBinaryStream(1, ins, b.length);
        pstmt.executeUpdate();
        conn.commit();
        ins.close();
        pstmt.close();
        conn.close();
    }

    /**
     * XQuery查询数据
     *
     * @throws SQLException
     */

    public static void testQueryXMLTable() throws SQLException {
        String query_sql = "SELECT XMLQUERY (\n" +
                "'declare default element namespace \"http://posample.org\";\n" +
                "for $d in $doc/customerinfo\n" +
                "return <out>{$d/name}</out>'\n" +
                "passing INFO as \"doc\")\n" +
                "FROM Customer as c\n" +
                "WHERE XMLEXISTS ('declare default element namespace \"http://posample.org\";\n" +
                "$i/customerinfo/addr[city=\"zhengzhou\"]' passing c.INFO as \"i\")";
        Connection conn = DBUtils.makeConnection();
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery(query_sql);
        StringBuffer xmls = new StringBuffer();
        while (rs.next()) {
            xmls.append(rs.getString(1)).append("\n");
        }
        System.out.println(xmls.toString());
        stmt.close();
        conn.close();
    }

    /**
     * XQuery更新数据
     *
     * @throws SQLException
     * @throws IOException
     */

    public static void testUpdateXMLTable() throws SQLException, IOException {
        String xml = "<customerinfo xmlns=\"http://posample.org\" Cid=\"1002\">\n" +
                "<name>Jim Noodle</name>\n" +
                "<addr country=\"Canada\">\n" +
                "<street>1150 Maple Drive</street>\n" +
                "<city>Newtown</city>\n" +
                "<prov-state>Ontario</prov-state>\n" +
                "<pcode-zip>Z9Z 2P2</pcode-zip>\n" +
                "</addr>\n" +
                "<phone type=\"work\">905-555-7258</phone>\n" +
                "</customerinfo>";
        String up_sql = "UPDATE customer SET info =?" +
                "WHERE XMLEXISTS (\n" +
                "'declare default element namespace \"http://posample.org\";\n" +
                "$doc/customerinfo[@Cid = 1000]'\n" +
                "passing INFO as \"doc\")";

        Connection conn = DBUtils.makeConnection();
        conn.setAutoCommit(false);
        PreparedStatement pstmt = conn.prepareStatement(up_sql);
        byte[] b = xml.getBytes();
        InputStream ins = new ByteArrayInputStream(b);
        pstmt.setBinaryStream(1, ins, b.length);
        pstmt.executeUpdate();
        conn.commit();
        ins.close();
        pstmt.close();
        conn.close();
    }

    /**
     * 查询xml列数据,用于验证
     *
     * @throws SQLException
     */

    public static void testQueryXMLColumn() throws SQLException {
        String query_sql = "SELECT INFO FROM Customer";
        Connection conn = DBUtils.makeConnection();
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery(query_sql);
        StringBuffer xmls = new StringBuffer();
        while (rs.next()) {
            xmls.append(rs.getString(1)).append("\n");
        }
        System.out.println(xmls.toString());
        stmt.close();
        conn.close();
    }

    /**
     * 测试入口,方法组调用
     *
     * @param rags
     * @throws Exception
     */

    public static void main(String rags[]) throws Exception {
        testDropXMLTable();
        testCreateXMLTable();
        testInsertXMLTable();
        testQueryXMLTable();
        testUpdateXMLTable();
        testQueryXMLColumn();
    }
}
 
三、运行结果
 
<out xmlns="http://posample.org"><name>Robert Shoemaker</name></out>

<customerinfo xmlns="http://posample.org" Cid="1002"><name>Jim Noodle</name><addr country="Canada"><street>1150 Maple Drive</street><city>Newtown</city><prov-state>Ontario</prov-state><pcode-zip>Z9Z 2P2</pcode-zip></addr><phone type="work">905-555-7258</phone></customerinfo>


Process finished with exit code 0
 
呵呵,终于看到运行结果了。。。