SpringMVC（8）：使用JDBC+springmvc 完成useDao的查询和添加用户（小实验）-CFANZ编程社区

18/1/9

jdbc的操作非常简单，springmvc 最初也是直接跟jdbc打交道的。因此，我也做了个小Demo，要求如下：

1、给订单系统增加ConfigManager.java 工具类，来完成数据库配制文件的读取。该类设计为单例，考虑线程；

2、编写Junit测试类，测试查询用户和增加用户信息。

【0】文件结构：

SpringMVC（8）：使用JDBC+springmvc 完成useDao的查询和添加用户（小实验）_java

结果是单例的ConfigManager类出现了空指针异常，我会后续跟进。

【1】新建/database.properties文件：

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test/smbms_user
jdbc.username=root
jdbc.password=

【2】新建ConfigManager.java 文件（静态内部类的使用）：

package file.InnerClass;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;


public class ConfigManager {
  private static ConfigManager singleton;
  private static Properties properties;
  private ConfigManager(){
    //可以添加业务代码--整个系统运行只会执行一次的业务代码操作
    String configFile = "database.properties";
    properties = new Properties();
//    ConfigManager.class.getClassLoader();
//    InputStream is = ClassLoader.getSystemResourceAsStream(configFile);
    InputStream is = ConfigManager.class.getClassLoader().getResourceAsStream(configFile);
    try {
      properties.load(is);
      is.close();
    }catch(IOException e){
      e.printStackTrace();
    }
  }
  
  //Inner class
  public static class ConfigManagerHelper{
    private static final ConfigManager INSTANCE = new ConfigManager();
  }
  
  public static ConfigManager getInstance(){
    singleton = ConfigManagerHelper.INSTANCE;
    return singleton;
  }
  
  public static String getValue(String key){
    //API
    return properties.getProperty(key);
  }
}

【3】新建BaseDao.java文件：

package file.InnerClass;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;

import com.smbms.entities.User;

public class BaseDao {
  public static Connection getConnection(){
    Connection connection = null;
    ConfigManager.getInstance();
    String driver = ConfigManager.getValue("driver");
    ConfigManager.getInstance();
    String url = ConfigManager.getValue("url");
    ConfigManager.getInstance();
    String username = ConfigManager.getValue("username");
    ConfigManager.getInstance();
    String password = ConfigManager.getValue("password");
    try{
      Class.forName(driver);
      connection = DriverManager.getConnection(url,username,password);
      
    }catch(Exception e){
      e.getMessage();
    }
    return connection;
  }
  
  //连接得到statement
  public static Statement getStatement(Connection conn) throws SQLException{
    return conn.createStatement();
  }

  //返回一个user对象
  public static ArrayList<User> getUseList(ResultSet rs) throws SQLException{
    ArrayList<User> userList = new ArrayList<User>();
    User user = new User();
    while(rs.next()){
      user.setId(rs.getInt(0));
      user.setUserCode(rs.getString(1));
      user.setUserName(rs.getString(2));
      user.setUserPassword(rs.getString(3));
      user.setGender(rs.getInt(4));
      user.setBirthday(rs.getDate(5));
      user.setPhone(rs.getNString(6));
      user.setAddress(rs.getNString(7));
      user.setUserRole(rs.getInt(8));
      user.setCreatedBy(rs.getInt(9));
      user.setCreationDate(rs.getDate(10));
      userList.add(user);
    }
    return userList;
  }
  
  //添加一个user对象
  public static boolean addUser(String sql){
    boolean result =false;
    try {
      BaseDao.getConnection().createStatement().executeQuery(sql);
      result = true;
    } catch (SQLException e) {
      result =false;
      e.printStackTrace();
    }
    return result;
  }
}

【4】新建UserDao.java 文件：

package com.smbms.dao;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;

import com.smbms.entities.User;

import file.InnerClass.BaseDao;

public  class UserDao {
  public static ArrayList<User> allUserShow() throws SQLException{
    String sql = "select * from smbms_user";
//    ArrayList<User> allUser = new ArrayList<User>();
    System.out.println(sql);
    ResultSet rs = BaseDao.getConnection().createStatement().executeQuery(sql);
    return BaseDao.getUseList(rs);
  }
  
  public static boolean addNewUser(User user){
    boolean result =false;
    String sql = "insert into smbms_user"
        + "(userCode,userName,userPassword,gender,birthday,phone,address,userRole,createBy,createDate)"
        + "values"
        + "("+user.getUserCode()+","+user.getUserName()+","+
        user.getUserPassword()+","+user.getGender()+","+
        user.getBirthday()+","+user.getPhone()+","+user.getAddress()+","+
        user.getUserRole()+","+user.getCreatedBy()+","+user.getCreationDate()+");";
    System.out.println("***"+sql);
    result = BaseDao.addUser(sql);
    return result;
  }
}

解释：其实就是在BaseDao的基础上，再进行了一次封装。

【5】写个单元测试类：

package com.smbms.dao;

import java.sql.SQLException;
import java.util.ArrayList;

import org.junit.Test;

import com.smbms.entities.User;

public class UserDaoTest {

  @Test
  public void test() throws SQLException {
    UserDao userDao = new UserDao();
    User user = new User();
    user.setUserName("leilaohu");
    System.out.println("addusertest result: "+userDao.addNewUser(user));
    System.out.println("-==============");
    ArrayList<User> userList = new ArrayList<User>();
    userList = userDao.allUserShow();
    for(User u:userList){
      System.out.println(u.toString());
    }
    
  }

}

由于一个Bug还没解决，所以，之后会继续更新。

Log如下：

java.lang.NullPointerException
  at file.InnerClass.BaseDao.addUser(BaseDao.java:63)
  at com.smbms.dao.UserDao.addNewUser(UserDao.java:30)
  at com.smbms.dao.UserDaoTest.test(UserDaoTest.java:17)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
  at java.lang.reflect.Method.invoke(Unknown Source)
  at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
  at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
  at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
  at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
  at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
  at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
  at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
  at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
  at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
  at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
  at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
  at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
  at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
  at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
  at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
  at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
  at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
  at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
  at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)