以面向对象的思想实现数据表的添加和查询，JDBC代码超详细

Posted 2021-01-24

以面向对象的思想编写JDBC程序，实现使用java程序向数据表中添加学生信息，并且可以实现给定×××号查询学生信息或给定准考证号查询学生信息。

创建的数据表如下：

CREATE TABLE EXAMSTUDENT(
FlowID INTEGER,
Type INTEGER,
IDCard VARCHAR(18),
ExamCard VARCHAR(15),
StudentName VARCHAR(20),
Location VARCHAR(20),
Grade INTEGER);
1.首先实现通过java程序在创建的数据表中插入一个新的student信息，输入详细信息之后显示消息录入成功。

1).新建一个Student，对应examstudent数据表。

Student.java

package com.test.jdbc;
public class Student {
private int flowId;
private int type;
private String idCard;
private String examCard;
private String studentName;
private String location;
private int grade;
public int getFlowId() {
return flowId;
}
public void setFlowId(int flowId) {
this.flowId = flowId;
}
public int getType() {
return type;
}
public void setType(int type) {
this.type = type;
}
public String getIdCard() {
return idCard;
}
public void setIdCard(String idCard) {
this.idCard = idCard;
}
public String getExamCard() {
return examCard;
}
public void setExamCard(String 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;
}
public Student(int flowId, int type, String idCard, String examCard, String studentName, String location,
int grade) {
super();
this.flowId = flowId;
this.type = type;
this.idCard = idCard;
this.examCard = examCard;
this.studentName = studentName;
this.location = location;
this.grade = grade;
}
public Student(){ }br/>@Override
public String toString() {
return "student [flowId=" + flowId + ", type=" + type + ", idCard=" + idCard + ", examCard=" + examCard

• ", studentName=" + studentName + ", location=" + location + ", grade=" + grade + "]";
  }

}
2).新建一个方法：void addNewStudent(Student student)，把参数Student对象插入到数据库中。

public void addNewStudent(Student student){
//1.准备符合要求的sql语句
String sql="INSERT INTO examstudent VALUES("+student.getFlowId()+","+student.getType()
+","+student.getIdCard()+","+student.getExamCard()+","+student.getStudentName()+","+
student.getLocation()+","+student.getGrade()+")";
System.out.println(sql);
//2.调用JDBCTools类的update(sql)方法执行插入操作
JDBCTools.update(sql);
}
3).从控制台输入学生的信息。

private Student getStudentFromConsole() {
Scanner scanner=new Scanner(System.in);
Student student=new Student();
System.out.print("FlowId:");
student.setFlowId(scanner.nextInt());
System.out.print("Type:");
student.setType(scanner.nextInt());
System.out.print("IDCard:");
student.setIdCard(scanner.next());
System.out.print("ExamCard:");
student.setExamCard(scanner.next());
System.out.print("StudentName:");
student.setStudentName(scanner.next());
System.out.print("Location:");
student.setLocation(scanner.next());
System.out.print("Grade:");
student.setGrade(scanner.nextInt());

return student;
}
4).方法调用并测试

@Test<br>public void testAddNewStudent(){
Student student=getStudentFromConsole();
addNewStudent(student);
}
2.给定×××号或准考证号查询学生信息

public void testGetStudent(){
//1.得到查询的类型
int searchType=getSearchTypeFromConsole();
//2.具体查询学生信息
Student student=searchStudent(searchType);
//3.打印学生信息
printStudent(student);
}
1).得到查询类型

private int getSearchTypeFromConsole() {
System.out.println("查询类型：1.根据×××号查询学生信息 2.根据准考证号查询学生信息 ");
System.out.print("请输入查询类型：");
Scanner scanner=new Scanner(System.in);
int type=scanner.nextInt();
if ((type!=1)&&(type!=2)){
System.out.print("1.根据×××号查询学生信息 2.根据准考证号查询学生信息.请重新输入查询类型:");
throw new RuntimeException();
}
return type;
}
2).具体查询学生信息

private Student searchStudent(int searchType) {
String sql="SELECT FlowID,TYPE,IDCard,ExamCard,StudentName,Location,Grade FROM EXAMSTUDENT WHERE ";
Scanner scanner=new Scanner(System.in);
if (searchType==1){
System.out.print("请输入×××号：");
String str=scanner.next();
sql=sql+"IDCard="+"‘"+str+"‘";
}else{
System.out.print("请输入准考证号：");
String str=scanner.next();
sql=sql+"ExamCard"+"‘"+str+"‘";
}
Student student=getStudent(sql);
return student;
}
数据库操作获取学生信息：

private Student getStudent(String sql) {
Student stu=null;
Connection con=null;
Statement statement=null;
ResultSet resultset=null;

try{
con=JDBCTools.getConnection();
statement=con.createStatement();
resultset=statement.executeQuery(sql);
if(resultset.next()){
stu=new Student(resultset.getInt(1),resultset.getInt(2),
resultset.getString(3),resultset.getString(4),
resultset.getString(5),resultset.getString(6),resultset.getInt(7));
}
}catch(Exception e){
e.printStackTrace();
}finally{
JDBCTools.release(statement, con);
}
return stu;
}
3).打印学生信息

private void printStudent(Student student) {
if(student!=null){
System.out.println(student);
}else{
System.out.println("查无此人");
}
}
完整的示例代码：

Student.java(上面已给出)

数据库操作工具类：JDBCTools.java

package com.test.jdbc;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
import org.junit.Test;

public class JDBCTools {
//更新数据库
public static void update(String sql){
Connection con=null;
Statement statement=null;
try{
con=JDBCTools.getConnection();
statement=con.createStatement();
statement.executeUpdate(sql);
}catch(Exception e){
e.printStackTrace();
}finally{
JDBCTools.release(statement, con);
}
}
//获取数据库的连接
public static Connection getConnection() throws Exception{
String driverClass=null;
String jdbcUrl=null;
String user=null;
String password=null;

InputStream in=JDBCTools.class.getResourceAsStream("/jdbc.properties");
Properties properties=new Properties();
properties.load(in);

driverClass=properties.getProperty("driver");
jdbcUrl=properties.getProperty("jdbcUrl");
user=properties.getProperty("user");
password=properties.getProperty("password");

Class.forName(driverClass);
Connection connection=DriverManager.getConnection(jdbcUrl,user,password);

return connection;br/>}
@Test
public void testGetConnection() throws Exception{
getConnection();
}
//数据库释放
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();
}
}
}
}
功能实现类：JDBCTest.java

package com.test.jdbc;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Scanner;
import org.junit.Test;

public class JDBCTest {br/>@Test
public void testGetStudent(){
//1.得到查询的类型
int searchType=getSearchTypeFromConsole();
//2.具体查询学生信息
Student student=searchStudent(searchType);
//3.打印学生信息
printStudent(student);
}
private void printStudent(Student student) {
if(student!=null){
System.out.println(student);
}else{
System.out.println("查无此人");
}
}
private Student searchStudent(int searchType) {
String sql="SELECT FlowID,TYPE,IDCard,ExamCard,StudentName,Location,Grade FROM EXAMSTUDENT WHERE ";
Scanner scanner=new Scanner(System.in);
if (searchType==1){
System.out.print("请输入×××号：");
String str=scanner.next();
sql=sql+"IDCard="+"‘"+str+"‘";
}else{
System.out.print("请输入准考证号：");
String str=scanner.next();
sql=sql+"ExamCard"+"‘"+str+"‘";
}
Student student=getStudent(sql);
return student;
}
private Student getStudent(String sql) {
Student stu=null;
Connection con=null;
Statement statement=null;
ResultSet resultset=null;

try{
con=JDBCTools.getConnection();
statement=con.createStatement();
resultset=statement.executeQuery(sql);
if(resultset.next()){
stu=new Student(resultset.getInt(1),resultset.getInt(2),
resultset.getString(3),resultset.getString(4),
resultset.getString(5),resultset.getString(6),resultset.getInt(7));
}
}catch(Exception e){
e.printStackTrace();
}finally{
JDBCTools.release(statement, con);
}
return stu;
}
private int getSearchTypeFromConsole() {
System.out.println("查询类型：1.根据×××号查询学生信息 2.根据准考证号查询学生信息 ");
System.out.print("请输入查询类型：");
Scanner scanner=new Scanner(System.in);
int type=scanner.nextInt();
if ((type!=1)&&(type!=2)){
System.out.print("1.根据×××号查询学生信息 2.根据准考证号查询学生信息.请重新输入查询类型:");
throw new RuntimeException();
}
return type;br/>}
@Test
public void testAddNewStudent(){
Student student=getStudentFromConsole();
addNewStudent(student);
}
//从控制台输入学生的信息
private Student getStudentFromConsole() {
Scanner scanner=new Scanner(System.in);
Student student=new Student();
System.out.print("FlowId:");
student.setFlowId(scanner.nextInt());
System.out.print("Type:");
student.setType(scanner.nextInt());
System.out.print("IDCard:");
student.setIdCard(scanner.next());
System.out.print("ExamCard:");
student.setExamCard(scanner.next());
System.out.print("StudentName:");
student.setStudentName(scanner.next());
System.out.print("Location:");
student.setLocation(scanner.next());
System.out.print("Grade:");
student.setGrade(scanner.nextInt());

return student;
}
public void addNewStudent(Student student){
//1.准备符合要求的sql语句
String sql="INSERT INTO examstudent VALUES("+student.getFlowId()+","+student.getType()
+","+student.getIdCard()+","+student.getExamCard()+","+student.getStudentName()+","+
student.getLocation()+","+student.getGrade()+")";
System.out.println(sql);
//2.调用JDBCTools类的update(sql)方法执行插入操作
JDBCTools.update(sql);
}
}