QueryRunner使用案例

QueryRunner使用   http://blog.sina.com.cn/s/blog_64e467d60100u1uu.html 在相继学习了JDBC和数据库操作之后，我们明显感到编写JDBC代码并非一件轻松的事儿。为了帮助我们更高效的学习工作，从JDBC的繁重代码中解脱出来，老佟给我们详尽介绍了一个简化JDBC操作的组件——DBUtils。我们今天主要学习了它所提供的两个类和一个接口。
组件下载地址：http://commons.apache.org/dbutils/
DbUtils类(org.apache.commons.dbutils.DbUtils)主要负责装载驱动、关闭连接的常规工作。
1、close: 检查所提供的参数是不是NULL，如果不是的话，它们就关闭连接、声明和结果集。
2、CloseQuietly:避免连接、声明或结果集为NULL的情况被关闭。
3、CommitAndCloseQuietly(Connection conn)：用来提交连接，然后关闭连接，并且在关闭连接时不向上抛出在关闭时发生的一些SQL异常。
4、LoadDriver(String driveClassName): 装载并注册JDBC驱动程序，如果成功就返回TRUE。
QreryRunner类(org.apache.commons.dbutils.QueryRunner) 显著的简化了SQL查询，并与ResultSetHandler协同工作将使编码量大为减少。
1、query(Connection conn, String sql, Object[] params, ResultSetHandler rsh)：执行选择查询，在查询中，对象阵列的值被用来作为查询的置换参数。
2、query(String sql, Object[] params, ResultSetHandler rsh)：方法本身不提供数据库连接，执行选择查询，在查询中，对象阵列的值被用来作为查询的置换参数。
3、query(Connection conn, String sql, ResultSetHandler rsh)：执行无需参数的选择查询。
4、update(Connection conn, String sql, Object[] params)：被用来执行插入、更新或删除（DML）操作。
ResultSetHandler接口(org.apache.commons.dbutils.ResultSethandler)执行处理一个结果集对象，将数据转变并处理为任何一种形式，供其他应用使用。
1、Object handle (java.sql.ResultSet .rs) ：结果集（ResultSet）作为参数传入方法内，处理这个结果集，返回一个对象。
ArrayHandler
ArrayListHandler
BeanHandler
BeanListHandler
MapHandler
MapListHandler
ScalarHandler
我们学习了此组件的两个类和一个接口以后，写了下列代码供参考。
import java.sql.Connection;
import java.sql.SQLException;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanListHandler;
public class TestQueryRunner {
public static void main(String[] args) throws SQLException {
//queryOracle();
update();
}
private static void update() throws SQLException{
QueryRunner runner = new QueryRunner();
Connection conn = DBManager.getConnection();
String sql = "UPDATE examstudent SET student_name = ? WHERE flow_id = ?"; //删除非 manager 中工资 低于 5000 的员工
Object [] params = new Object[]{"Jerry", 5000};
runner.update(conn, sql, params);
}
private static void insert() throws SQLException{
QueryRunner runner = new QueryRunner();
Connection conn = DBManager.getConnection();
String sql = "INSERT INTO examstudent(flow_id, type, id_card, exam_card, student_name, location, grade) VALUES(?, ?, ?, ?, ?, ?, ?)"; //删除非 manager 中工资 低于 5000 的员工
Object [] params = new Object[]{5000, 6, "身份证", "准考证", "Tom", "北京", 99};
runner.update(conn, sql, params);
}
private static void delete() throws SQLException{
QueryRunner runner = new QueryRunner();
Connection conn = DBManager.getConnection();
//删除非 manager 中工资 低于 5000 的员工
String sql = "delete from employees " + "where employee_id not in " +
"     (select distinct d.manager_id from departments d where d.manager_id is not null) " +
"and salary < ?";
System.out.println(sql);
Object [] params = new Object[]{5000};
runner.update(conn, sql, params);
}
private static void queryOracle() throws SQLException{
QueryRunner runner = new QueryRunner();
Connection conn = DBManager.getConnection();
//oracle 中的别名可以别解析
String sql = "SELECT flow_id flowid, type, id_card idcard, exam_card examcard, student_name studentname, location, grade FROM examstudent";
Object obj = runner.query(conn, sql, new BeanListHandler(ExamStudent.class));
System.out.println(obj);
}
private static void query() throws SQLException {
//1. 创建一个 QueryRunner 的实例
QueryRunner runner = new QueryRunner();
Connection conn = DBManager.getConnection();
String sql = "SELECT id, name, address, phone FROM customers WHERE name LIKE ?";
Class type = Customer.class;
Object [] params = new Object[]{"%%"};
//2. 查询操作
//conn: 查询需要的数据库连接, sql: 查询使用的 sql 语句, rsh: 如何转换查询得到的结果集, params: 填补 sql 语句参数的数组
Object obj = runner.query(conn, sql, new BeanListHandler(type), params);
//System.out.println("^^" + obj);
sql = "SELECT flow_id flowid, type, id_card idcard, exam_card examcard, student_name studentname, location, grade FROM examstudent";
type = ExamStudent.class;
obj = runner.query(conn, sql, new BeanListHandler(ExamStudent.class));
System.out.println(obj);
}
}

package cn.imau.utils;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import javax.persistence.Column;
import javax.persistence.Table;
import javax.sql.DataSource;

import org.apache.commons.dbutils.ResultSetHandler;
public class QueryRunner extends org.apache.commons.dbutils.QueryRunner{
//添加save方法
/**
* 对传递的bean进行分析
* 将t对象转成insert into users
*/
public <T> T save(T t) throws Exception{
//获取类
Class<?> cls = t.getClass();
//从这个字节码上获取name值这个就是表名
Table table = cls.getAnnotation(Table.class);
//获取表名
String tableName = table.name();
//组成insert into users(id,name,pwd) values('id',"name','');
String sql = "insert into "+tableName;
String cols="(";
String values="values(";

//获取所有声明的字段
Field[] fs = cls.getDeclaredFields();
//遍历所有字段
for(Field f:fs){
if(f.isAnnotationPresent(Column.class)){
//获取列名
String colName = f.getName();
//获取column的对象
Column col = f.getAnnotation(Column.class);
if(col.name()!=null && !col.name().trim().equals("")){
colName=col.name();
}
//获取列值
f.setAccessible(true);
//获取列值
Object value = f.get(t);
if(cols.equals("(")){
cols+=colName;
if(value instanceof String){
values+="'"+value+"'";
}else{
values+=value;
}

}else{
cols+=","+colName;
if(value instanceof String){
values+=",'"+value+"'";
}else{
values+=","+value;
}
}
}
}
cols+=")";
values+=")";
sql = sql+cols+" "+values;
System.err.println(sql);
update(sql);
return t;
}

public QueryRunner() {
}
public QueryRunner(DataSource ds){
super(ds);
}
@Override
public int[] batch(Connection arg0, String arg1, Object[][] arg2){
try {
return super.batch(arg0, arg1, arg2);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}
}
@Override
public int[] batch(String sql, Object[][] params){
try {
return super.batch(sql, params);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
protected void close(Connection conn) {
try {
super.close(conn);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
protected void close(ResultSet rs){
try {
super.close(rs);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}
}

@Override
protected void close(Statement stmt){
try {
super.close(stmt);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}
}

@Override
public void fillStatement(PreparedStatement arg0, Object... arg1)
{
try {
super.fillStatement(arg0, arg1);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public void fillStatementWithBean(PreparedStatement arg0, Object arg1,
PropertyDescriptor[] arg2){
try {
super.fillStatementWithBean(arg0, arg1, arg2);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public void fillStatementWithBean(PreparedStatement arg0, Object arg1,
String... arg2) {
try {
super.fillStatementWithBean(arg0, arg1, arg2);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public DataSource getDataSource() {
return super.getDataSource();
}

@Override
protected Connection prepareConnection() {
try {
return super.prepareConnection();
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
protected PreparedStatement prepareStatement(Connection conn, String sql)
{
try {
return super.prepareStatement(conn, sql);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public <T> T query(Connection conn, String sql, Object param,
ResultSetHandler<T> rsh) {
try {
return super.query(conn, sql, param, rsh);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public <T> T query(Connection conn, String sql, Object[] params,
ResultSetHandler<T> rsh) {
try {
return super.query(conn, sql, params, rsh);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

public <T> T query(Connection arg0, String arg1, ResultSetHandler<T> arg2,
Object... arg3){
try {
return super.query(arg0, arg1, arg2, arg3);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public <T> T query(Connection conn, String sql, ResultSetHandler<T> rsh)
{
try {
return super.query(conn, sql, rsh);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public <T> T query(String sql, Object param, ResultSetHandler<T> rsh)
{
try {
return super.query(sql, param, rsh);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public <T> T query(String sql, Object[] params, ResultSetHandler<T> rsh)
{
try {
return super.query(sql, params, rsh);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public <T> T query(String sql, ResultSetHandler<T> rsh, Object... params)
{
try {
return super.query(sql, rsh, params);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public <T> T query(String sql, ResultSetHandler<T> rsh){
try {
return super.query(sql, rsh);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
protected void rethrow(SQLException cause, String sql, Object... params)
{
try {
super.rethrow(cause, sql, params);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public int update(Connection arg0, String arg1, Object... arg2)
{
try {
return super.update(arg0, arg1, arg2);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public int update(Connection conn, String sql, Object param)
{
try {
return super.update(conn, sql, param);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public int update(Connection conn, String sql) {
try {
return super.update(conn, sql);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public int update(String sql, Object... params){
try {
return super.update(sql, params);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public int update(String sql, Object param){
try {
return super.update(sql, param);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
public int update(String sql) {
try {
return super.update(sql);
} catch (SQLException e) {
throw new RuntimeException(e.getMessage(),e);
}

}

@Override
protected ResultSet wrap(ResultSet rs) {
return super.wrap(rs);
}
}