DBUtils使用详细示例

　　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

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


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/>

* 编码：wallimn　时间：2012-7-25　上午11:07:06<br/>

* 版本：V1.0<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;

}

}