JDBC24homework

编写程序:

创建一个类DBTools,在DBTools中创建一个方法find,find方法用于对数据库进行查询操作,现在要求将结果集封装成数组线性表嵌套数组的形式:

ArrayList<String[]> rsList = new ArrayList<String[]>()形式

其中:    String[] 用于存储一行记录的所有字段(的值)

              rsList存储所有的数组(String[]),即记录的总数

 

 1,需要先创建一个用户的基本信息作为一个类,这样在其他类中可以直接定义为此类类型的对象。

  1 package com.xt.java.base25;
  2 
  3 public class User {
  4     
  5     private String userId;
  6     
  7     private String userName;
  8     
  9     private String password;
 10     
 11     private String email;
 12     
 13     private String telNo;
 14     
 15     private String gender;
 16     
 17     private String memo;
 18     
 19     private double salary;
 20 
 21     /**
 22      * @return the userId
 23      */
 24     public String getUserId() {
 25         return userId;
 26     }
 27 
 28     /**
 29      * @param userId the userId to set
 30      */
 31     public void setUserId(String userId) {
 32         this.userId = userId;
 33     }
 34 
 35     /**
 36      * @return the userName
 37      */
 38     public String getUserName() {
 39         return userName;
 40     }
 41 
 42     /**
 43      * @param userName the userName to set
 44      */
 45     public void setUserName(String userName) {
 46         this.userName = userName;
 47     }
 48 
 49     /**
 50      * @return the password
 51      */
 52     public String getPassword() {
 53         return password;
 54     }
 55 
 56     /**
 57      * @param password the password to set
 58      */
 59     public void setPassword(String password) {
 60         this.password = password;
 61     }
 62 
 63     /**
 64      * @return the email
 65      */
 66     public String getEmail() {
 67         return email;
 68     }
 69 
 70     /**
 71      * @param email the email to set
 72      */
 73     public void setEmail(String email) {
 74         this.email = email;
 75     }
 76 
 77     /**
 78      * @return the telNo
 79      */
 80     public String getTelNo() {
 81         return telNo;
 82     }
 83 
 84     /**
 85      * @param telNo the telNo to set
 86      */
 87     public void setTelNo(String telNo) {
 88         this.telNo = telNo;
 89     }
 90 
 91     /**
 92      * @return the gender
 93      */
 94     public String getGender() {
 95         return gender;
 96     }
 97 
 98     /**
 99      * @param gender the gender to set
100      */
101     public void setGender(String gender) {
102         this.gender = gender;
103     }
104 
105     /**
106      * @return the memo
107      */
108     public String getMemo() {
109         return memo;
110     }
111 
112     /**
113      * @param memo the memo to set
114      */
115     public void setMemo(String memo) {
116         this.memo = memo;
117     }
118 
119     /**
120      * @return the salary
121      */
122     public double getSalary() {
123         return salary;
124     }
125 
126     /**
127      * @param salary the salary to set
128      */
129     public void setSalary(double salary) {
130         this.salary = salary;
131     }
132 
133     /* (non-Javadoc)
134      * @see java.lang.Object#toString()
135      */
136     @Override
137     public String toString() {
138         return "User [userId=" + userId + ", userName=" + userName + ", password=" + password + ", email=" + email
139                 + ", telNo=" + telNo + ", gender=" + gender + ", memo=" + memo + ", salary=" + salary + "]";
140     }
141     
142     
143     
144 
145 }

2,创建一个数据库databases access objected和数据库建立联系直接调用,这样写一次就行了

package com.xt.java.base25;

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

public class UserDAO {
    private Connection conn;
    private Statement stat;
    private String  url="jdbc:mysql://localhost:3306/lyxdatabases";
    private String dbDriver="com.mysql.jdbc.Driver";
    private String userName="root";
    private String password="1234";
    //私有的构造方法,只有在本类中可以进行实例化一次,为了保护用户的隐私使用这种方法,切记!!!
    private UserDAO(){
        
    }
        
    private static UserDAO uda=null;
    /**
     * 写一个方法,从方法中获得实例,只能实例化一次。
     */
    
    public static UserDAO getUserDAO(){
        if(uda==null){
            uda=new UserDAO();
        }
        return uda;
    }
    
    public Connection getConnection() throws Exception{
          try {
            Class.forName(dbDriver);
            return DriverManager.getConnection(url,userName,password);
        } catch (ClassNotFoundException e) {
            throw new ClassNotFoundException("数据库找不到驱动!!");
        } catch (SQLException e) {
            throw new SQLException("数据库连接异常!!");
        }
    }
    
    //关闭Connection
    public void closeConnection(Connection conn){
        try{
            if(conn!=null){
                conn.close();
            }
            
        }catch(Exception e){
            System.out.println(e);
        }
    }

    
    //关闭Statement
    public void closeStatement(Statement stat){
        try{
            if(stat!=null){
                stat.close();
            }
            
        }catch(Exception e){
            System.out.println(e);
        }
    }
    //关闭ResultSet
    public void closeResultSet(ResultSet rs){
        try{
            if(rs!=null){
                rs.close();
            }
            
        }catch(Exception e){
            System.out.println(e);
        }
    }
}

3

创建一个类DBTools,在DBTools中创建一个方法find,find方法用于对数据库进行查询操作,现在要求将结果集封装成数组线性表嵌套数组的形式:

ArrayList<String[]> rsList = new ArrayList<String[]>()形式

 

package com.xt.java.base25;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Iterator;

/**
 * 创建一个类DBTools,在DBTools中创建一个方法find,find方法用于对数据库进行查询操作,
 * 现在要求将结果集封装成数组线性表嵌套数组的形式:
ArrayList<String[]> rsList = new ArrayList<String[]>()形式
其中:    String[] 用于存储一行记录的所有字段(的值)
        rsList存储所有的数组(String[]),即记录的总数


 * @author LENOVO
 *
 */
public class DBtools {
    Connection conn;
    Statement stat;
    ResultSet rs;
    UserDAO udao=UserDAO.getUserDAO();
    
    public void find(String userID){
        ArrayList<String> rsList=new ArrayList<String>(20);
        String sql="select*from user where userID="+userID;
        
        try {
            conn=udao.getConnection();
            stat=conn.createStatement();
            rs=stat.executeQuery(sql);
            while(rs.next()){
                User user=new User();
                user.setUserId(rs.getString(1));
                user.setUserName(rs.getString(2));
                user.setPassword(rs.getString(3));
                user.setEmail(rs.getString(4));
                user.setTelNo(rs.getString(5));
                user.setGender(rs.getString(6));
                user.setMemo(rs.getString(7));
                user.setSalary(rs.getDouble(8));
                
            rsList.add(user.toString());
            }
            Iterator<String> iterator=rsList.iterator();
            while(iterator.hasNext()){
                System.out.println(iterator.next());
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            udao.closeResultSet(rs);
            udao.closeStatement(stat);
            udao.closeConnection(conn);
        }
        
        
    }
    public static void main(String[] args) {
        DBtools dbt=new DBtools();
        dbt.find("123");
        
        
    }

}

 

posted @ 2017-08-19 14:57  木&子  阅读(249)  评论(0编辑  收藏  举报