从控制台输入输出，来进行数据库的插入和查询操作的小程序详解数据库

package examStudent; 
 
public class ExamStudent { 
    /** 
     * 流水号 
     */ 
    private int flowId; 
 
    /** 
     * 四级、六级 
     */ 
    private int type; 
 
    /** 
     * 身份证号码 
     */ 
    private int idCard; 
 
    /** 
     * 准考证号码 
     */ 
    private int examCard; 
 
    /** 
     * 学生姓名 
     */ 
    private String studentName; 
 
    /** 
     * 区域 
     */ 
    private String location; 
 
    /** 
     * 成绩 
     */ 
    private int grade; 
 
    public int getFlowId() { 
        return flowId; 
    } 
 
    public int getType() { 
        return type; 
    } 
 
    public void setType(int type) { 
        this.type = type; 
    } 
 
    public int getIdCard() { 
        return idCard; 
    } 
 
    public void setIdCard(int idCard) { 
        this.idCard = idCard; 
    } 
 
    public int getExamCard() { 
        return examCard; 
    } 
 
    public void setExamCard(int examCard) { 
        this.examCard = examCard; 
    } 
 
    public String getStudentName() { 
        return studentName; 
    } 
 
    public void setStudentName(String studentName) { 
        this.studentName = studentName; 
    } 
 
    public String getLocation() { 
        return location; 
    } 
 
    public void setLocation(String location) { 
        this.location = location; 
    } 
 
    public int getGrade() { 
        return grade; 
    } 
 
    public void setGrade(int grade) { 
        this.grade = grade; 
    } 
}

package examStudent; 
 
import java.util.List; 
import java.util.Scanner; 
 
import org.junit.Test; 
 
import tools.SqlTools; 
 
public class ExamStudentDao { 
    /** 
     * 插入一条数据 
     */ 
    public void update() { 
        ExamStudent examStudent = new ExamStudent(); 
        // 从控制台输入 Type,idCard,examCard,studentName,location,grade 
        Scanner sc = new Scanner(System.in); 
        System.out.println("请输入考生的详细信息"); 
        System.out.print("Type: "); 
        int type = sc.nextInt(); 
        System.out.print("IDCard: "); 
        int idCard = sc.nextInt(); 
        System.out.print("ExamCard: "); 
        int examCard = sc.nextInt(); 
        System.out.print("StudentName: "); 
        String studentName = sc.next(); 
        System.out.print("Location: "); 
        String location = sc.next(); 
        System.out.print("Grade: "); 
        int grade = sc.nextInt(); 
        // 将从控制台输入的值分别写入ExamStudent中 
        examStudent.setType(type); 
        examStudent.setIdCard(idCard); 
        examStudent.setExamCard(examCard); 
        examStudent.setStudentName(studentName); 
        examStudent.setLocation(location); 
        examStudent.setGrade(grade); 
        // sql文 
        String sql = "INSERT INTO exam_student (TYPE,ID_CARD,EXAM_CARD,STUDENT_NAME,LOCATION,GRADE) VALUES ('" 
                + examStudent.getType() + "','" + examStudent.getIdCard() + "','" + examStudent.getExamCard() + "','" 
                + examStudent.getStudentName() + "','" + examStudent.getLocation() + "','" + examStudent.getGrade() 
                + "')"; 
        // 插入一条数据 
        SqlTools.update(sql); 
        System.out.println("插入成功"); 
    } 
 
    /** 
     * 根据身份证号码进行查询 
     */ 
    public List findByIdCard(String idCard) { 
        String sql = "SELECT * FROM EXAM_STUDENT WHERE ID_CARD=" + idCard; 
        List list = SqlTools.findOne(sql); 
        return list; 
    } 
 
    /** 
     * 根据准考证号码进行查询 
     */ 
    public List findByExamCard(String examCard) { 
        String sql = "SELECT * FROM EXAM_STUDENT WHERE EXAM_CARD=" + examCard; 
        List<ExamStudent> list = SqlTools.findOne(sql); 
        return list; 
    } 
}

package examStudent; 
 
import java.util.List; 
import java.util.Scanner; 
 
public class TestExamStudent { 
    public static void main(String[] args) { 
        ExamStudentDao esd = new ExamStudentDao(); 
        ExamStudent es = new ExamStudent(); 
        Scanner sc = new Scanner(System.in); 
        System.out.println("输入1插入，输入2查询"); 
        int temp = sc.nextInt(); 
        if(temp == 1){ 
            esd.update(); 
        }else if(temp == 2){ 
            System.out.println("进入查询系统"); 
            System.out.println("请选择您要输入的类型："); 
            System.out.println("3:准考证号"); 
            System.out.println("4:身份证号"); 
            int cardType = sc.nextInt(); 
            if(cardType == 3){ 
                System.out.println("请输入证件号码"); 
                String cardNum = sc.next(); 
                List list = esd.findByExamCard(cardNum); 
                for (Object obj : list) { 
                    System.out.println(obj); 
                } 
            } 
            else if(cardType == 4){ 
                System.out.println("请输入证件号码"); 
                String cardNum = sc.next(); 
                List list = esd.findByIdCard(cardNum); 
                if(list.isEmpty()){ 
                    System.out.println("查无此人"); 
                }else{ 
                    for (Object obj : list) { 
                        System.out.println(obj); 
                    } 
                } 
            } 
            else{ 
                System.out.println("系统异常退出"); 
            } 
        }else{ 
            System.out.println("系统退出"); 
        } 
    } 
}

jdbcName=mySql

driver=com.mysql.jdbc.Driver 
jdbcUrl=jdbc:mysql://localhost:3306/dic 
user=root 
password=123456

package tools; 
import java.io.IOException; 
import java.io.InputStream; 
import java.sql.Connection; 
import java.sql.DriverManager; 
import java.sql.ResultSet; 
import java.sql.SQLException; 
import java.sql.Statement; 
import java.util.Properties; 
/** 
* JDBC 的工具类 
*/ 
public class JDBCTools { 
/** 
* 关闭ResultSet，Statement，Connection 
*/ 
public static void release(ResultSet rs, Statement statement, Connection connection) { 
if (rs != null) { 
try { 
rs.close(); 
} catch (SQLException e) { 
e.printStackTrace(); 
} 
} 
if (statement != null) { 
try { 
statement.close(); 
} catch (SQLException e) { 
e.printStackTrace(); 
} 
} 
if (connection != null) { 
try { 
connection.close(); 
} catch (SQLException e) { 
e.printStackTrace(); 
} 
} 
} 
/** 
* 关闭Statement,Connection 
*  
* @param statement 
* @param connection 
*/ 
public static void release(Statement statement, Connection connection) { 
if (statement != null) { 
try { 
statement.close(); 
} catch (SQLException e) { 
e.printStackTrace(); 
} 
} 
if (connection != null) { 
try { 
connection.close(); 
} catch (SQLException e) { 
e.printStackTrace(); 
} 
} 
} 
/** 
* 获取数据库连接的方法 
*  
* @return 
* @throws Exception 
*/ 
public static Connection getConnection() { 
// 准备连接数据库的四个字符串 
// 驱动的全类名 
String driverClass = null; 
String jdbcUrl = null; 
String user = null; 
String password = null; 
String jdbcName = null; 
// 读取jdbcName.properties文件 
InputStream inStream = JDBCTools.class.getClassLoader().getResourceAsStream("properties/jdbcName.properties"); 
Properties propertiesOfName = new Properties(); 
try { 
propertiesOfName.load(inStream); 
} catch (IOException e) { 
e.printStackTrace(); 
} 
jdbcName = propertiesOfName.getProperty("jdbcName"); 
// 读取需要的properties 文件 
InputStream in = JDBCTools.class.getClassLoader().getResourceAsStream("properties/" + jdbcName + ".properties"); 
Properties properties = new Properties(); 
try { 
properties.load(in); 
} catch (IOException e) { 
e.printStackTrace(); 
} 
driverClass = properties.getProperty("driver"); 
jdbcUrl = properties.getProperty("jdbcUrl"); 
user = properties.getProperty("user"); 
password = properties.getProperty("password"); 
// 加载数据库驱动程序(注册驱动) 
try { 
Class.forName(driverClass); 
} catch (ClassNotFoundException e) { 
e.printStackTrace(); 
} 
Connection connection = null; 
try { 
connection = DriverManager.getConnection(jdbcUrl, user, password); 
} catch (SQLException e) { 
e.printStackTrace(); 
} 
return connection; 
} 
}

package tools; 
import java.sql.Connection; 
import java.sql.ResultSet; 
import java.sql.ResultSetMetaData; 
import java.sql.Statement; 
import java.util.ArrayList; 
import java.util.HashMap; 
import java.util.List; 
import java.util.Map; 
public class SqlTools { 
/** 
* 通用的更新方法：包括INSERT/UPDATE/DELETE 
*  
* @param sql 
*/ 
public static void update(String sql) { 
Connection connection = null; 
Statement statement = null; 
try { 
connection = JDBCTools.getConnection(); 
statement = connection.createStatement(); 
statement.executeUpdate(sql); 
} catch (Exception e) { 
e.printStackTrace(); 
} finally { 
JDBCTools.release(statement, connection); 
} 
} 
/** 
* 通用的查询方法：SELECT 
*/ 
@SuppressWarnings({ "unchecked", "rawtypes" }) 
public static List findOne(String sql) { 
Connection connection = null; 
Statement statement = null; 
ResultSet rs = null; 
try { 
// 1.获取Connection 
connection = JDBCTools.getConnection(); 
// 2.获取Statement 
statement = connection.createStatement(); 
// 4.执行查询，得到ResultSet 
rs = statement.executeQuery(sql); 
// 5.处理ResultSet 
List list = new ArrayList(); 
ResultSetMetaData metaData = rs.getMetaData(); 
int columnCount = metaData.getColumnCount(); 
while (rs.next()) { 
Map rowData = new HashMap(); 
for (int i = 1; i < columnCount; i++) { 
rowData.put(metaData.getColumnName(i), rs.getObject(i)); 
} 
list.add(rowData); 
} 
return list; 
} catch (Exception e) { 
e.printStackTrace(); 
return null; 
} finally { 
// 6.关闭数据库相应的资源 
            JDBCTools.release(rs, statement, connection); 
} 
} 
}