Java JDBC crud有參
阿新 • • 發佈：2018-12-17
1.屬性類，儲存屬性以及set，get，toString方法
package java_n20.entity; import java.util.Date; /** * ClassName: Emp * @Description: 屬性類 * @author cai * @date 2018年10月23日 */ public class Emp { private Integer id; private String name; private String sex; private Date birth; private String departemnt; private String address; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } @Override public String toString() { return "Emp [id=" + id + ", name=" + name + ", sex=" + sex + ", birth=" + birth + ", departemnt=" + departemnt + ", address=" + address + "]"; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } public Date getBirth() { return birth; } public void setBirth(Date birth) { this.birth = birth; } public String getDepartemnt() { return departemnt; } public void setDepartemnt(String departemnt) { this.departemnt = departemnt; } public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } }
2.配置檔案
jdbc.name = root
jdbc.password = 2510.62
jdbc.url = jdbc:mysql://localhost/demo?useSSL=true&characterEncoding=utf8
jdbc.driver = com.mysql.jdbc.Driver3.Mysql連線工具類
package java_n20.util; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.util.Properties; /** * ClassName: DBHelper * @Description: 獲得資料庫連線的工具類 * @author cai * @date 2018年10月22日 */ public class DBHelper { //1.使用者名稱 private static String name; //2.密碼 private static String password; //3.地址 private static String url; //4.驅動，從外部引進mysql-connector-jar檔案 private static String driver; static { Properties prop = new Properties(); try { //1.讀取jdbc.properties檔案的內容 prop.load(new FileInputStream(new File("src/jdbc.properties"))); name = prop.getProperty("jdbc.name"); url = prop.getProperty("jdbc.url"); password = prop.getProperty("jdbc.password"); driver = prop.getProperty("jdbc.driver"); //2.載入驅動 Class.forName(driver); } catch (IOException e) { e.printStackTrace(); } catch (ClassNotFoundException e) { e.printStackTrace(); } } public static Connection getDBConnection() { //工具類方法一般為靜態，而且是不能例項化的 Connection conn= null; try { //3.獲得連線 conn= DriverManager.getConnection(url, name, password); } catch (SQLException e) { e.printStackTrace(); } return conn; } private DBHelper() { } }
4.介面類
package java_n20.dao; import java.util.List; import java_n20.entity.Emp; /** * ClassName: EmpDao * @Description: 介面，統一方法 * @author cai * @date 2018年10月23日 */ public interface EmpDao { public Integer addEmp(Emp emp) throws Exception; //因為傳輸的內容比較多，所以使用物件方便一些 public Integer deleteEmp(int id) throws Exception; public Integer updateEmp(Emp emp) throws Exception; //修改欄位的時候，要修改的數量並不一定，所以使用物件 public Emp selectOneEmp(String name) throws Exception; public List<Emp> selectAll() throws Exception; public void selectByPage() throws Exception; public void selectCount() throws Exception; }
5.介面實現類
package java_n20.dao.impl;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import java_n20.dao.EmpDao;
import java_n20.entity.Emp;
import java_n20.util.DBHelper;
/**
* ClassName: EmpDaoImpl
* @Description: 介面實現類
* @author cai
* @date 2018年10月23日
*/
public class EmpDaoImpl implements EmpDao{
private Connection conn = null;
private PreparedStatement ps = null;
ResultSet rs =null;
/**
* 新增員工 insert
*/
@Override
public Integer addEmp(Emp emp) throws Exception {
//1.獲得資料庫連線
conn = DBHelper.getDBConnection();
//2.準備sql語句
String sql = "insert into student (id,name) values (?,?)";
//3.(預)編譯sql Statement-->Preparement(預編譯物件，存放的是編譯後的sql語句)
//Preparement 用於將引數化的sql語句傳送到資料庫
//PreparedStatement表示預編譯的sql語句的物件，sql語句已預編譯並存儲在這個物件中
ps = conn.prepareStatement(sql);
//3.1如果有佔位符，此處給佔位符賦值
ps.setInt(1,emp.getId()); //(佔位符位置，引數) 比如此處第一個佔位符
ps.setString(2, emp.getName());
//4.執行sql新增
int num = ps.executeUpdate(); //返回值表示更改的記錄數,返回0一般表示失敗
//5.關閉連線，釋放資源
conn.close();
return num;
}
@Override
public Integer deleteEmp(int id) throws Exception {
conn = DBHelper.getDBConnection();
String sql = "delete from student where id = ?";
ps = conn.prepareStatement(sql);
ps.setInt(1, id);
//4.執行sql刪除
int num = ps.executeUpdate();
conn.close();
return num;
}
@Override
public Integer updateEmp(Emp emp) throws Exception {
conn = DBHelper.getDBConnection();
String sql = "update student set name=? where id = ?";
ps = conn.prepareStatement(sql);
ps.setString(1, emp.getName());
ps.setInt(2, emp.getId());
//4.執行sql更改
int num = ps.executeUpdate();
conn.close();
return num;
}
@Override
public Emp selectOneEmp(String na) throws Exception {
conn = DBHelper.getDBConnection();
String sql = "select * from student where name = ccc";
ps = conn.prepareStatement(sql);
ps.setString(1, na);
//4.執行sql查詢
rs = ps.executeQuery(); //返回一個結果集，是資料庫裡面查詢的資料資訊
//4.1獲取返回的資料資訊
Emp emp = new Emp();
if(rs.next()) { //指標下一行有沒有資料
String name = rs.getString("name"); //引數為列資訊
String sex = rs.getString("sex");
emp.setName(name);
emp.setSex(sex);
}
//5.關閉
rs.close();
ps.close();
conn.close();
return emp;
}
@Override
public List<Emp> selectAll() throws Exception {
conn = DBHelper.getDBConnection();
String sql = "select * from student";
ps = conn.prepareStatement(sql);
//4.執行sql查詢
rs = ps.executeQuery(); //返回一個結果集，是資料庫裡面查詢的資料資訊
//4.1獲取返回的資料資訊
List<Emp> empList=new ArrayList<>();
while(rs.next()) { //指標下一行有沒有資料
String name = rs.getString("name"); //引數為列資訊
String sex = rs.getString("sex");
Emp emp = new Emp();
emp.setName(name);
emp.setName(sex);
empList.add(emp);
}
//5.關閉
rs.close();
ps.close();
conn.close();
return null;
}
@Override
public void selectByPage() throws Exception {
conn = DBHelper.getDBConnection();
String sql = "select * from student limit 0,5";
ps = conn.prepareStatement(sql);
//4.執行sql查詢
rs = ps.executeQuery(); //返回一個結果集，是資料庫裡面查詢的資料資訊
//4.1獲取返回的資料資訊
while(rs.next()) { //指標下一行有沒有資料
String name = rs.getString("name"); //引數為列資訊
String sex = rs.getString("sex");
System.out.println(name+sex);
}
//5.關閉
rs.close();
ps.close();
conn.close();
}
@Override
public void selectCount() throws Exception {
conn = DBHelper.getDBConnection();
String sql = "select count(*) from student";
ps = conn.prepareStatement(sql);
//4.執行sql查詢
rs = ps.executeQuery(); //返回一個結果集，是資料庫裡面查詢的資料資訊
//4.1獲取返回的資料資訊
while(rs.next()) { //指標下一行有沒有資料
int total = rs.getInt("count(*)");
System.out.println(total);
}
//5.關閉
rs.close();
ps.close();
conn.close();
}
}6.測試類
package java_n20.test;
import java_n20.dao.EmpDao;
import java_n20.dao.impl.EmpDaoImpl;
import java_n20.entity.Emp;
/**
* ClassName: TestEmp
* @Description: 測試類
* @author cai
* @date 2018年10月23日
*/
public class TestEmp {
public static void main(String[] args) {
EmpDao empDao = new EmpDaoImpl();
//要傳輸的資料
int id = 000;
String name = "cc";
Emp emp = new Emp();
emp.setId(id);
emp.setName(name);
try {
int num= empDao.addEmp(emp);
if(num==1){
System.out.println("新增成功");
}
empDao.updateEmp(emp);
} catch (Exception e) {
e.printStackTrace();
}
}
}