DBUtils使用详细示例（参考）

原文链接为：http://wallimn.iteye.com/blog/1606930

用了好长一段时间JAVA，今天才知道有DBUtils这个东西。看了一下，使用方便，上手很快，是个不错的东西。 

一、使用示例 

package com.exam.test;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import junit.framework.TestCase;
import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.ArrayHandler;
import org.apache.commons.dbutils.handlers.ArrayListHandler;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.ColumnListHandler;
import org.apache.commons.dbutils.handlers.MapHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.apache.commons.dbutils.handlers.ScalarHandler;
import com.exam.db.DbManager;
import com.exam.util.BasicRowProcessorEx;

public class TestSomething extends TestCase {
    public void testDBUtilSelect() {
        Connection conn = DbManager.getInstance().getConnection();

        QueryRunner queryRunner = new QueryRunner();

        try {
            // 返回单行记录，使用Map
            System.out.println("使用Map处理单行记录！");
            Map<String, Object> map = queryRunner.query(conn,
                    "select * from tab where rownum=1", new MapHandler(),
                    (Object[]) null);

            for (Iterator<Entry<String, Object>> i = map.entrySet().iterator(); i
                    .hasNext();) {
                Entry<String, Object> e = i.next();
                System.out.println(e.getKey() + "=" + e.getValue());
            }

            System.out.println("处理多行记录！");
            List<Map<String, Object>> list = queryRunner.query(conn,
                    "select * from tab where rownum<=3", new MapListHandler(),
                    (Object[]) null);

            for (Iterator<Map<String, Object>> li = list.iterator(); li
                    .hasNext();) {
                System.out.println("--------------");
                Map<String, Object> m = li.next();
                for (Iterator<Entry<String, Object>> mi = m.entrySet()
                        .iterator(); mi.hasNext();) {
                    Entry<String, Object> e = mi.next();
                    System.out.println(e.getKey() + "=" + e.getValue());
                }
            }

            System.out.println("使用Bean处理单行记录！");

            // com.exam.test.TestSomething.Tab
            Tab tab = queryRunner.query(conn,
                    "select tname from tab where rownum=1",
                    new BeanHandler<Tab>(Tab.class));
            System.out.println("tname=" + tab.getTname());
            System.out.println("tabtype=" + tab.getTabtype());

            System.out.println("使用Array处理单行记录！");
            Object[] array = queryRunner.query(conn,
                    "select * from tab where rownum=1", new ArrayHandler());

            for (int i = 0; i < array.length; i++) {
                System.out.println(array[i]);
            }

            System.out.println("使用Array处理多行记录！");
            List<Object[]> arraylist = queryRunner
                    .query(conn, "select * from tab where rownum<=3",
                            new ArrayListHandler());

            for (Iterator<Object[]> itr = arraylist.iterator(); itr.hasNext();) {
                Object[] a = itr.next();
                System.out.println("--------------");
                for (int i = 0; i < a.length; i++) {
                    System.out.println(a[i]);

                }
            }

            System.out.println("使用ColumnListHandler处理单行记录，返回其中指定的一列！");
            List<Object> colList = queryRunner.query(conn,
                    "select * from tab where rownum=1", new ColumnListHandler(
                            "tname"));
            for (Iterator<Object> itr = colList.iterator(); itr.hasNext();) {
                System.out.println(itr.next());
            }

            System.out
                    .println("使用ScalarHandler处理单行记录，只返回结果集第一行中的指定字段，如未指定字段，则返回第一个字段！");
            Object scalar1 = queryRunner.query(conn, "select * from tab",
                    new ScalarHandler("tname"));
            System.out.println(scalar1);
            Object scalar2 = queryRunner.query(conn,
                    "select tname,tabtype from tab", new ScalarHandler());
            System.out.println(scalar2);

            // 使用自定义的行处理器
            // Map中的KEY可按输入顺序输出
            System.out.println("使用Map处理单行记录(使用自定义行处理器)！");
            Map<String, Object> linkedmap = queryRunner
                    .query(
                            conn,
                            "select tabtype,tname,'wallimn' as programmer from tab where rownum=1",
                            new MapHandler(new BasicRowProcessorEx()),
                            (Object[]) null);

            for (Iterator<Entry<String, Object>> i = linkedmap.entrySet()
                    .iterator(); i.hasNext();) {
                Entry<String, Object> e = i.next();
                System.out.println(e.getKey() + "=" + e.getValue());
            }

            // 使用自定义的行处理器
            // Map中的KEY可按输入顺序输出
            System.out.println("处理多行记录(使用自定义行处理器)！");
            List<Map<String, Object>> listLinedMap = queryRunner
                    .query(
                            conn,
                            "select tabtype,tname,'wallimn' as programmer from tab where rownum<=3",
                            new MapListHandler(new BasicRowProcessorEx()),
                            (Object[]) null);

            for (Iterator<Map<String, Object>> li = listLinedMap.iterator(); li
                    .hasNext();) {
                System.out.println("--------------");
                Map<String, Object> m = li.next();
                for (Iterator<Entry<String, Object>> mi = m.entrySet()
                        .iterator(); mi.hasNext();) {
                    Entry<String, Object> e = mi.next();
                    System.out.println(e.getKey() + "=" + e.getValue());
                }
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        DbUtils.closeQuietly(conn);
    }

    public void testDBUtilInsertDeleteUpdateSelect() {
        // 建一个简单的测试表，建表脚本如下
        // create table T_DBUTILTEST(
        // id integer,
        // name varchar2(255)
        // );
        Connection conn = DbManager.getInstance().getConnection();

        QueryRunner queryRunner = new QueryRunner(true);

        try {
            queryRunner.update(conn, "delete from T_DBUTILTEST");
            // queryRunner.update(conn, "truncate table T_DBUTILTEST");
            // 插一条
            for (int i = 0; i < 10; i++) {
                queryRunner.update(conn,
                        "insert into T_DBUTILTEST (id,name) values (?,?)", i,
                        "http://wallimn.iteye.com");
            }

            // 再插多条
            queryRunner.batch(conn,
                    "insert into T_DBUTILTEST (id,name) values (?,?)",
                    new Object[][] { { 11, "batch:wallimn@sohu.com" },
                            { 12, "batch:wallimn@sohu.com" } });

            // 删除示例
            queryRunner.update(conn, "delete from T_DBUTILTEST where id=1");
            queryRunner.update(conn, "delete from T_DBUTILTEST where id=?", 2);
            queryRunner.batch(conn, "delete from T_DBUTILTEST where id=?",
                    new Object[][] { { 3 }, { 4 } });

            // 修改示例
            queryRunner.update(conn,
                    "update T_DBUTILTEST set name = ? where id=?", "修改后的新值", 5);

            System.out.println("最终结果显示结果");
            List<Map<String, Object>> list = queryRunner.query(conn,
                    "select name,id from T_DBUTILTEST", new MapListHandler(),
                    (Object[]) null);

            for (Iterator<Map<String, Object>> li = list.iterator(); li
                    .hasNext();) {
                System.out.println("--------------");
                Map<String, Object> m = li.next();
                for (Iterator<Entry<String, Object>> mi = m.entrySet()
                        .iterator(); mi.hasNext();) {
                    Entry<String, Object> e = mi.next();
                    System.out.print(e.getValue());
                    System.out.print(",");
                }
                System.out.println();
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        DbUtils.closeQuietly(conn);
    }
}

二、自定义扩展 
　　如果用户想要依照存入Map的顺序显示内容，好像不能直接支持。看了看源码，自定义了一个扩展类。用法在前的代码中有示例。 

package com.exam.util;

import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;

import org.apache.commons.dbutils.BasicRowProcessor;

/**
 * 用于apache的dbutil类的功能改进，当需要Map中的Key能按输入的顺序输出时，使用这个类来进行处理。简单改了一下基类。<br/>
 */
public class BasicRowProcessorEx extends BasicRowProcessor {

    private static class CaseInsensitiveLinkedHashMap extends HashMap<String, Object> {
        private final Map<String, String> lowerCaseMap = new LinkedHashMap<String, String>();
        private static final long serialVersionUID = -2848100435296897392L;

        /** {@inheritDoc} */
        @Override
        public boolean containsKey(Object key) {
            Object realKey = lowerCaseMap.get(key.toString().toLowerCase());
            return super.containsKey(realKey);
        }

        /** {@inheritDoc} */
        @Override
        public Object get(Object key) {
            Object realKey = lowerCaseMap.get(key.toString().toLowerCase());
            return super.get(realKey);
        }

        /** {@inheritDoc} */
        @Override
        public Object put(String key, Object value) {
            Object oldKey = lowerCaseMap.put(key.toLowerCase(), key);
            Object oldValue = super.remove(oldKey);
            super.put(key, value);
            return oldValue;
        }

        /** {@inheritDoc} */
        @Override
        public void putAll(Map<? extends String, ?> m) {
            for (Map.Entry<? extends String, ?> entry : m.entrySet()) {
                String key = entry.getKey();
                Object value = entry.getValue();
                this.put(key, value);
            }
        }

        /** {@inheritDoc} */
        @Override
        public Object remove(Object key) {
            Object realKey = lowerCaseMap.remove(key.toString().toLowerCase());
            return super.remove(realKey);
        }
    }
    @Override
    public Map<String, Object> toMap(ResultSet rs) throws SQLException {
        Map<String, Object> result = new CaseInsensitiveLinkedHashMap();
        ResultSetMetaData rsmd = rs.getMetaData();
        int cols = rsmd.getColumnCount();

        for (int i = 1; i <= cols; i++) {
            result.put(rsmd.getColumnName(i), rs.getObject(i));
        }

        return result;
    }

}