DbUtils工具类使用

创建数据库

 CREATE TABLE `student` (`userId` int(11) NOT NULL,`userName` varchar(30) NOT NULL,`gender` char(1) NOT NULL,`age` int(11) DEFAULT NULL,PRIMARY KEY (`userId`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8

把相关的包引入到项目里:

编写Student类:

package com.t0.test;public class Student {private Integer userId;private String userName;private String gender;private Integer age;public Integer getUserId() {return userId;}public void setUserId(Integer userId) {this.userId = userId;}public String getUserName() {return userName;}public void setUserName(String userName) {this.userName = userName;}public String getGender() {return gender;}public void setGender(String gender) {this.gender = gender;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}@Overridepublic String toString() {return "student [userId=" + userId + ", userName=" + userName + ", gender=" + gender + ", age=" + age + "]";}}

代码:

package com.t0.test;import java.util.Properties;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import javax.sql.DataSource;import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.ResultSetHandler;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.KeyedHandler;
import org.apache.commons.dbutils.handlers.MapHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;public class TestDbUtils {private static Log log = LogFactory.getLog(TestDbUtils.class);private DataSource createDataSource(Properties props) {MysqlDataSource ds = new MysqlDataSource();ds.setURL(props.getProperty("url"));ds.setUser(props.getProperty("user"));ds.setPassword(props.getProperty("password"));return ds;}/*** 创建数据源* @return*/
//  private DataSource createDataSource() {
//      MysqlDataSource ds = new MysqlDataSource();
//      ds.setURL("jdbc:mysql://localhost:3306/test");
//      ds.setUser("root");
//      ds.setPassword("root__");
//      return ds;
//  }/*** 将查询结查返回一个数据列表List* @param ds*/public void queryBeanList(DataSource ds) {String sql = "select userId, userName, gender, age from student";QueryRunner queryRunner = new QueryRunner(ds);ResultSetHandler<List<Student>> handler = new BeanListHandler<Student>(Student.class);List<Student> result = null;try {result = queryRunner.query(sql, handler);} catch(SQLException e) {e.printStackTrace();}if (null == result) {return;}for (Student s : result) {System.out.println(s);}}/*** 将查询结果返一个Bean* @param ds* @param id*/public void queryBean(DataSource ds, int id) {String sql = "select * from student where userId = ?";QueryRunner queryRunner = new QueryRunner(ds);ResultSetHandler<Student> handler = new BeanHandler<Student>(Student.class);Student result = null;try {result = queryRunner.query(sql, handler, id);} catch(SQLException e) {e.printStackTrace();}if (null == result) {return;}System.out.println(result);}/*** 将查询结果以键值对列表形式返回* @param */public void queryMapList(DataSource ds) {String sql = "select userId, userName, gender, age from student";QueryRunner queryRunner = new QueryRunner(ds);ResultSetHandler<List<Map<String, Object>>> handler = new MapListHandler();List<Map<String, Object>> result = null;try {result = queryRunner.query(sql, handler);} catch (SQLException e) {e.printStackTrace();}if (null == result) {return;}for (Map<String, Object> map : result) {System.out.println(map);}}/*** 将查询结果以键值对形式返回* @param ds* @param id*/public void queryMap(DataSource ds, int id) {String sql = "select * from student where userId = ?";QueryRunner queryRunner = new QueryRunner(ds);ResultSetHandler<Map<String, Object>> handler = new MapHandler();Map<String, Object> result = null;try {result = queryRunner.query(sql, handler, id);} catch (SQLException e) {e.printStackTrace();}if (null == result) {return;}System.out.println(result);}/*** 自定义处理,其实也将查询结果* @param ds*/public void queryCustomHandler(DataSource ds) {String sql = "select userId, userName, gender, age from student";QueryRunner queryRunner = new QueryRunner(ds);ResultSetHandler<List<Student>> handler = new ResultSetHandler<List<Student>>() {@Overridepublic List<Student> handle(ResultSet paramResultSet) throws SQLException {List<Student> list = new ArrayList<Student>();while (paramResultSet.next()) {Student student = new Student();student.setUserId(paramResultSet.getInt("userId"));student.setUserName(paramResultSet.getString("userName"));student.setGender(paramResultSet.getString("gender"));student.setAge(paramResultSet.getInt("age"));list.add(student);}return list;}};List<Student> result = null;try {result = queryRunner.query(sql, handler);} catch (SQLException e) {e.printStackTrace();}if (null == result ) {return;}for (Student student : result) {System.out.println(student);}}public int updateBean(DataSource ds,Student s) {int n = 0;String sql = "insert into student(userId, userName, gender, age) values('?','?','?','?');";QueryRunner queryRunner = new QueryRunner(ds);try {n = queryRunner.update(sql,s.getUserId(),s.getUserName(), s.getGender(), s.getAge() );if (0 == n) {return 0;}System.out.println("插入了 " + n + " 个数据!" );} catch (SQLException e) {e.printStackTrace();}return n;}public int insertBean(DataSource ds, Student s) {int n = 0;String sql = "insert into student(userId, userName, gender, age) values(?,?,?,?)";QueryRunner queryRunner = new QueryRunner(ds);try {
//          n = queryRunner.update(sql, new Object[] {"22", "二2222", "M","22"} );n = queryRunner.update(sql,new Object[] {s.getUserId(), s.getUserName(), s.getGender(), s.getAge()});} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}return n;}public static void main(String[] args) {Properties properties = new Properties();properties.setProperty("url", "jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF8");properties.setProperty("user", "root");properties.setProperty("password", "root__");// TODO Auto-generated method stubTestDbUtils tDbUtils = new TestDbUtils();
//      DataSource ds = tDbUtils.createDataSource();DataSource ds = tDbUtils.createDataSource(properties);System.out.println("-------queryBeanList--------");tDbUtils.queryBeanList(ds);System.out.println("-------queryBean--------");tDbUtils.queryBean(ds, 5);System.out.println("-------queryMapList--------");tDbUtils.queryMapList(ds);System.out.println("-------queryMap--------");tDbUtils.queryMap(ds, 6);System.out.println("-------queryCustomHandler-------");tDbUtils.queryCustomHandler(ds);System.out.println("============================================");Student s = new Student();s.setUserId(13);s.setUserName("十3郎");s.setGender("M");s.setAge(34);tDbUtils.insertBean(ds, s);}}

执行结果:

注意:DbUtils使用中,SQL语句中不能用单引号,我也是花了N长时间没有找到原因,至少,我是用了单引号把问号括起来一直报错.提示不需要参数,就是问号的作用没有发挥.