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 {

private final Map lowerCaseMap = new LinkedHashMap();

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 toMap(ResultSet rs) throws SQLException {

Map 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;

}

}