DBUtils使用详细示例

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
Java代码
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。
Java代码 收藏代码
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。
  

• 编码：wallimn　时间：2012-7-25　上午11:07:06
  

• 版本：V1.0
  
  */
  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;  
  

  }

}