一、什么是dbutils
commons-dbutils 是 Apache 组织提供的一个开源 JDBC工具类库，它是对JDBC的简单封装，学习成本极低，并且使用dbutils能极大简化jdbc编码的工作量，同时也不会影响程序的性能。因此dbutils成为很多不喜欢hibernate的公司的首选。
二、dbutils核心API
1、QueryRunner类
使用QueryRunner实现增删改查
1 package com.dbutils;
2
3 import java.sql.SQLException;
4 import java.util.Date;
5 import java.util.List;
6
7 import org.apache.commons.dbutils.QueryRunner;
8 import org.apache.commons.dbutils.handlers.BeanHandler;
9 import org.apache.commons.dbutils.handlers.BeanListHandler;
10 import org.junit.Test;
11
12 import com.domain.User;
13 import com.utils.JdbcUtils;
14
15 /**
16 *
17 * 使用dbutils完成数据库的增删改查
18 *
19 */
20 public class Demo1 {
21 // 插入
22 @Test
23 public void insert() throws SQLException {
24 QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
25 String sql = "insert into users(id,name,password,email,birthday) values(?,?,?,?,?)";
26 Object params[] = { 1, "aa", "123", "[email protected]", new Date() };
27 runner.update(sql, params);
28 }
29
30 // 删除
31 @Test
32 public void delete() throws SQLException {
33 QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
34 String sql = "delete from users where id=?";
35 runner.update(sql, 2);
36 }
37
38 // 修改
39 @Test
40 public void update() throws SQLException {
41 QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
42 String sql = "update users set email=? where id=?";
43 Object params[] = { "[email protected]", 2 };
44 runner.update(sql, params);
45 }
46
47 // 查找单条记录
48 @Test
49 public void find() throws SQLException {
50 QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
51 String sql = "select * from users where id=?";
52 User user = (User) runner.query(sql, 1, new BeanHandler(User.class));
53 System.out.println(user.getEmail());
54 }
55
56 // 查找所有记录
57 @Test
58 public void getAll() throws SQLException {
59 QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
60 String sql = "select * from users";
61 List<User> list = (List) runner.query(sql, new BeanListHandler(
62 User.class));
63 for (User user : list) {
64 System.out.println(user.getEmail());
65 }
66 }
67
68 // 批处理
69 @Test
70 public void batch() throws SQLException {
71 QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
72 String sql = "insert into users(id,name,password,email,birthday) values(?,?,?,?,?)";
73
74 //三条sql，五个参数
75 Object params[][] = new Object[3][5];
76
77 for(int i=0;i<params.length;i++){
78 params[i] = new Object[]{i+1,"aaa"+i,"123","sina.com",new Date()};
79 }
80
81 runner.batch(sql, params);
82 }
83
84 }
1 public class JdbcUtils {
2 private static DataSource ds;
3 static{
4 try {
5 Properties prop = new Properties();
6 InputStream in = JdbcUtils.class.getClassLoader().getResourceAsStream("dbcpconfig.properties");
7 prop.load(in);
8
9 //创建数据源
10 BasicDataSourceFactory factory = new BasicDataSourceFactory();
11 ds = factory.createDataSource(prop);
12 } catch (Exception e) {
13 throw new ExceptionInInitializerError(e);
14 }
15 }
16
17 //提供数据源
18 public static DataSource getDataSource(){
19 return ds;
20 }
21
22 //获取连接
23 public static Connection getConnection() throws SQLException{
24 return ds.getConnection();
25 }
26 }
2、ResultSetHandler接口的实现类
ArrayHandler：把结果集中的第一行数据转成对象数组。
ArrayListHandler：把结果集中的每一行数据都转成一个数组，再存放到List中。
BeanHandler：将结果集中的第一行数据封装到一个对应的JavaBean实例中。
BeanListHandler：将结果集中的每一行数据都封装到一个对应的JavaBean实例中，存放到List里。
ColumnListHandler：将结果集中某一列的数据存放到List中。
KeyedHandler(name)：将结果集中的每一行数据都封装到一个Map里，再把这些map再存到一个map里，其key为指定的key。
MapHandler：将结果集中的第一行数据封装到一个Map里，key是列名，value就是对应的值。
MapListHandler：将结果集中的每一行数据都封装到一个Map里，然后再存放到List
1 package com.dbutils;
2 import java.sql.SQLException;
3 import java.util.Arrays;
4 import java.util.List;
5 import java.util.Map;
6
7 import javax.swing.JButton;
8 import org.apache.commons.dbutils.QueryRunner;
9 import org.apache.commons.dbutils.handlers.ArrayHandler;
10 import org.apache.commons.dbutils.handlers.ArrayListHandler;
11 import org.apache.commons.dbutils.handlers.ColumnListHandler;
12 import org.apache.commons.dbutils.handlers.KeyedHandler;
13 import org.apache.commons.dbutils.handlers.ScalarHandler;
14 import org.junit.Test;
15
16 import com.utils.JdbcUtils;
17
18 /**
19 *
20 * dbutils结果集
21 *
22 */
23 public class Demo2 {
24 @Test
25 //把结果的第一行数据封装到数组中
26 public void test1() throws SQLException{
27 QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
28 String sql = "select * from users";
29 //强转的时候要加[]
30 Object result[] = (Object[]) runner.query(sql, new ArrayHandler());
31 System.out.println(result[0]);
32 System.out.println(result[1]);
33 }
34
35 @Test
36 //把结果的每行数据封装到数组中，在把数据存放在list集合中
37 public void test2() throws SQLException{
38 QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
39 String sql = "select * from users";
40 List<Object[]> list = (List) runner.query(sql, new ArrayListHandler());
41 System.out.println(list);
42 for(Object[] objects : list){
43 System.out.println(Arrays.toString(objects));
44 }
45 }
46
47 @Test
48 //把结果集的某一列封装到一个list集合中
49 public void test3() throws SQLException{
50 QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
51 String sql = "select * from users";
52
53 List list1 = (List) runner.query(sql, new ColumnListHandler());
54 for(Object object : list1){
55 System.out.println(object);
56 }
57
58 List list2 = (List) runner.query(sql,new ColumnListHandler("name"));
59 for(Object object : list2){
60 System.out.println(object);
61 }
62
63 List list3 = (List) runner.query(sql,new ColumnListHandler(4));
64 for(Object object : list3){
65 System.out.println(object);
66 }
67 }
68
69 //KeyedHandler(name)：将结果集中的每一行数据都封装到一个Map里，再把这些map再存到一个map里，其key为指定的key
70 @Test
71 public void test4() throws SQLException{
72 QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
73 String sql = "select * from users";
74 Map<Integer,Map<String,Object>> map = (Map) runner.query(sql, new KeyedHandler("id"));
75 for(Map.Entry<Integer, Map<String, Object>> me : map.entrySet()){
76 int key = me.getKey();
77
78 //拿到封装每条记录的map
79 for(Map.Entry<String, Object> entry:me.getValue().entrySet()){
80 System.out.println(entry.getKey()+"="+entry.getValue());
81 }
82 }
83 }
84
85
86 @Test
87 //获取记录总数
88 public void test5() throws SQLException{
89 QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource());
90 String sql = "select count(*) from users";
91 //Object result[] = (Object[]) runner.query(sql, new ArrayHandler());
92 /*long totalrecord = (Long)result[0];
93 int num = (int)totalrecord;
94 System.out.println(num);
95 int totalrecord = ((Long)result[0]).intValue();
96 */
97 int totalrecord = ((Long)runner.query(sql, new ScalarHandler(1))).intValue();
98 System.out.println(totalrecord);
99 }
100
101
102 }