天气网城市代码（MYSQL）获取实现

MYSQL数据库存储城市代码实现

在这篇/article/8254419.html文章中，说的是城市代码的MYSQL数据库方式的存储实现，这篇具体讲述实现方法。

实现类CityDB.java

/**
* @2013-12-18
* @author eabour
* @file CityDB.java
*  All Rights Reserved!
*/
package com.eabour.weather;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import com.eabour.jdbc.ConnectionPool;
import com.eabour.tool.LogUtil;

/**
* @author eabour
* @create 2013-12-18 下午2:44:59
*/
public class CityDB {

private ConnectionPool pool;
private final String PROV_TABLE="province";
private final String CITY_TABLE="city";
private final String DIST_TABLE="distract";

public CityDB(){
this.pool=ConnectionPool.getInstance();
}

/**
*
* @author eabour
* @throws SQLException
* @create 2013-12-18 下午2:50:15
*
* @function:
*/
public void getCitCode() throws SQLException{
Connection con=pool.getConnection();
try{
Statement stmt=con.createStatement();
/*
* DROP TABLE IF EXISTS `province`;
* DROP TABLE IF EXISTS `city`;
* DROP TABLE IF EXISTS `distract`;
*
*/
/*
ResultSet tables=stmt.executeQuery("show tables");
boolean hasProv = false,hasCity = false,hasDist = false;
while(tables.next()){
String table=tables.getString(1);
if(PROV_TABLE.equals(table)) hasProv=true;
if(CITY_TABLE.equals(table)) hasCity=true;
if(DIST_TABLE.equals(table)) hasDist=true;
}
*/
con.setAutoCommit(false);

stmt.addBatch("DROP TABLE IF EXISTS " + DIST_TABLE);
stmt.addBatch("DROP TABLE IF EXISTS " + CITY_TABLE);
stmt.addBatch("DROP TABLE IF EXISTS " + PROV_TABLE);

stmt.executeBatch();

//con.setAutoCommit(true);
stmt.addBatch("CREATE TABLE " + PROV_TABLE + " " +
"(id varchar(10),name varchar(20),primary key(id)) ENGINE=InnoDB DEFAULT CHARSET=utf8");
stmt.addBatch("CREATE TABLE " + CITY_TABLE + " " +
"(id varchar(10),name varchar(20),pro_id varchar(10),primary key(id)," +
"foreign key(pro_id) references " + PROV_TABLE + "(id)) ENGINE=InnoDB DEFAULT CHARSET=utf8");
stmt.addBatch("CREATE TABLE " + DIST_TABLE + " " +
"(id varchar(10),name varchar(20),code varchar(15),city_id varchar(10)," +
"primary key(id),foreign key(city_id) references " + CITY_TABLE + "(id)) ENGINE=InnoDB DEFAULT CHARSET=utf8");

stmt.executeBatch();
con.commit();

CityCode cityutil=new CityCode();
//get Province list
Map<String,String> pro=cityutil.getProvinceList();
for(String key : pro.keySet()){
System.out.println(key + " : " + pro.get(key));
stmt.addBatch("INSERT INTO "+ PROV_TABLE + "(id,name) values(\'"+ key + "\',\'" + pro.get(key) + "\')");
}
stmt.executeBatch();
con.commit();
for(String key : pro.keySet()){
System.out.println(pro.get(key));
//get city list
Map<String,String> city=cityutil.getCityZone(key);
for(String city_key : city.keySet()){
System.out.println("    " + city.get(city_key));
stmt.addBatch("INSERT INTO "+ CITY_TABLE + " values(\'"+ city_key + "\',\'" + city.get(city_key) + "\',\'" + key + "\')");
//get distract list
Map<String,String> distract=cityutil.getCityZone(city_key);
for(String dis_key : distract.keySet()){
System.out.println("      " + distract.get(dis_key));
//get concrete information
Map<String,String> concrete=cityutil.getCityZone(dis_key);
stmt.addBatch("INSERT INTO "+ DIST_TABLE + " values(\'"+ dis_key + "\',\'" + distract.get(dis_key) + "\',\'" + concrete.get(dis_key) + "\',\'" + city_key + "\')");
}
}
stmt.executeBatch();
con.commit();
}
}finally{
con.setAutoCommit(true);
pool.release(con);
}
}

/**
* @param city
* @return
* @author eabour
* @create 2013-12-18 下午5:31:16
* @charset UTF-8
*
* @function: 根据参数city来查询该城市的代码
*/
public String getCode(String city){
Connection con=pool.getConnection();
try{
if(city == null || !city.matches("[\\u4E00-\\u9FA5]+")) return "不合法";
con.setAutoCommit(true);

PreparedStatement ps=con.prepareStatement("select code from "+DIST_TABLE+" where name = ?");
ps.setString(1, city);
ResultSet rs=ps.executeQuery();
if(rs.next()){
return rs.getString(1);
}

ps=con.prepareStatement("select id from "+ PROV_TABLE +" where name = ?");
ps.setString(1, city);
ResultSet rs1=ps.executeQuery();
List<String> list=new ArrayList<String>();
if(rs1.next()){
String id=rs1.getString(1);
ps=con.prepareStatement("select name from "+ CITY_TABLE +" where pro_id = ?");
ps.setString(1, id);
ResultSet rs2=ps.executeQuery();
while(rs2.next()){
list.add(rs2.getString(1));
}
return list.toString();
}

} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
LogUtil.logWarn(this.getClass(), "getCity", e.toString());
}finally{
pool.release(con);
}
return "Unable to search the city's name of " + city;
}
}

这就是主要实现类。

测试类：

public static void main(String[] args) throws SQLException {
// TODO Auto-generated method stub
ConnectionPool pool=ConnectionPool.getInstance();
pool.localInit();
System.out.println(new CityDB().getCode("西安")); }

这个是测试的主方法，ConnectionPool是个数据库连接池，pool.localinit()是对数据库的本地初始化，重要作用是初始化本地数据库的连接等，并建立池，好让用到数据库连接的语句使用，也可以自己创建Connection连接，都可以。

今天在编写该类时，遇见了一些异常，主要还是对Mysql数据库的不了解造成的，就是出现了在插入汉字的时候，出现异常为 ‘海南’ not in feild list ，当时不知道原因，以为是字段问题，但是改完字段名称后还是这样的。左后就直接在数据库中操作，而不是在java程序里，结果还是同样的错误。然后我就重新用navicat for mysql进行建表，相同的字段，结果还是不能存汉字，但是原先的一个表能存汉字，现在的错误为
“incorrect string value”，进过查阅资料得知，是Mysql字符编码的问题，要修改为utf8，最后在新建表时添加如下语句：ENGINE=InnoDB DEFAULT CHARSET=utf8
。

还有就是mysql中的 `（是在TAB键上面和1键前面的那个有波浪的键），就是加在表名和字段上面的，字符串的是'(单引号，不是 ` )。鉴于对MYSQL的研究不多，就不在讲述。

如有不当之处，还请指正！