QueryRunner类 的應用,以及ResultSetHandler 接口的实现类
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1 .该接口用于处理 java.sql.ResultSet,将数据按要求转换为另一种形式。
ResultSetHandler 接口提供了一个单独的方法:Object handle (java.sql.ResultSet .rs)。
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。
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3.示例代碼如下:
1.首先定義一實體類
package com.beiwo.day05.entity; import java.io.Serializable; import java.sql.Date; public class Person implements Serializable{ /** * */ private static final long serialVersionUID = 1L; private int id; private String name; private String password; private String email; private Date birthday; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public Date getBirthday() { return birthday; } public void setBirthday(Date birthday) { this.birthday = birthday; } public static long getSerialversionuid() { return serialVersionUID; } @Override public String toString() { return "Person [id=" + id + ", name=" + name + ", password=" + password + ", email=" + email + ", birthday=" + birthday + ", getId()=" + getId() + ", getName()=" + getName() + ", getPassword()=" + getPassword() + ", getEmail()=" + getEmail() + ", getBirthday()=" + getBirthday() + ", getClass()=" + getClass() + ", hashCode()=" + hashCode() + ", toString()=" + super.toString() + "]"; } }
測試查詢
package com.beiwo.day05.test; import java.sql.SQLException; import java.util.List; import java.util.Map; 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.BeanListHandler; 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 org.junit.Test; import com.beiwo.day05.entity.Person; import com.beiwo.day05.util.C3P0Util; public class TestDBUtils { @Test //把结果集中的每一行数据都转成一个数组,再存放到List中。 public void testArrayListHandler() throws SQLException{ QueryRunner qr = new QueryRunner(C3P0Util.getDataSource()); String sql = "SELECT * FROM person"; List<Object[]> list = qr.query(sql, new ArrayListHandler()); for (Object[] objects : list) { for (Object object : objects) { System.out.println(object); } System.out.println("-----------------------------"); } } @Test //把结果集中的第一行数据转成对象数组。 public void testArrayHandler() throws SQLException{ QueryRunner qr = new QueryRunner(C3P0Util.getDataSource()); String sql = "SELECT * FROM person"; Object[] object = qr.query(sql, new ArrayHandler()); for(Object object1 : object){ System.out.println(object1); } } // @Test 将结果集中某一列的数据存放到List中。 public void testColumnListHandler() throws SQLException{ QueryRunner qr = new QueryRunner(C3P0Util.getDataSource()); String sql = "SELECT name,password,email,birthday FROM person"; List<Object> persons = qr.query(sql, new ColumnListHandler(2)); for(Object object : persons){ System.out.println(object); } } @Test //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。 public void testMapHandler() throws SQLException{ QueryRunner qr = new QueryRunner(C3P0Util.getDataSource()); String sql = "SELECT * FROM person WHERE id=?"; Map<String, Object> map= qr.query(sql, new MapHandler(),1); for (Map.Entry<String, Object> m:map.entrySet()) { System.out.println(m.getKey() + "\t" + m.getValue()); } } @Test //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 public void testMapListHandler() throws SQLException{ QueryRunner qr = new QueryRunner(C3P0Util.getDataSource()); String sql = "SELECT * FROM person "; List<Map<String, Object>> list = qr.query(sql, new MapListHandler()); for (Map<String, Object> map : list) { for (Map.Entry<String, Object> m : map.entrySet()) { System.out.println(m.getKey() + "\t" + m.getValue()); } System.out.println("--------------------------------------------"); } } @Test //查询数据库中信息的总条数 public void testScalarHandler() throws SQLException{ QueryRunner qr = new QueryRunner(C3P0Util.getDataSource()); String sql = "SELECT COUNT(*) FROM person "; Long l = (Long)qr.query(sql, new ScalarHandler(1)); System.out.println(l); } @Test //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。 public void testBeanListHandler() throws SQLException{ QueryRunner qr = new QueryRunner(C3P0Util.getDataSource()); String sql = "SELECT * FROM person "; List<Person> list = qr.query(sql, new BeanListHandler<Person>(Person.class)); System.out.println(list); } @Test //将结果集中的第一行数据封装到一个对应的JavaBean实例中。 public void testBeanHandler() throws SQLException{ QueryRunner qr = new QueryRunner(C3P0Util.getDataSource()); String sql = "SELECT * FROM person WHERE id=?"; Person person = qr.query(sql, new BeanHandler<Person>(Person.class),1); System.out.println(person); } }
測試增刪改
package com.beiwo.day05.test; import java.sql.SQLException; import java.util.Date; import org.apache.commons.dbutils.QueryRunner; import org.junit.Test; import com.beiwo.day05.util.C3P0Util; public class TestUpDate { @Test public void testInsert() throws SQLException{ QueryRunner qRunner = new QueryRunner(C3P0Util.getDataSource()); String sql = "INSERT INTO person(name,password,email,birthday)VALUES(?,?,?,?)"; qRunner.update(sql, "ccc","789","[email protected]",new Date()); } @Test public void testUpDate1() throws SQLException{ QueryRunner qRunner = new QueryRunner(C3P0Util.getDataSource()); String sql = "UPDATE person SET name=‘www‘ WHERE id=2"; qRunner.update(sql); } @Test public void testUpDate2() throws SQLException{ QueryRunner qRunner = new QueryRunner(C3P0Util.getDataSource()); String sql = "DELETE FROM person WHERE id=6"; qRunner.update(sql); } }
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