1.User.java
package com.jike.entity;
public class User {
private int uId;
private String uName;
private int uAge;
private int classId;
public int getuId() {
return uId;
}
public void setuId(int uId) {
this.uId = uId;
}
public String getuName() {
return uName;
}
public void setuName(String uName) {
this.uName = uName;
}
public int getuAge() {
return uAge;
}
public void setuAge(int uAge) {
this.uAge = uAge;
}
public int getClassId() {
return classId;
}
public void setClassId(int classId) {
this.classId = classId;
}
}
2.BaseConnection.java
package com.jike.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
public class BaseConnection {
public static Connection getConnection() {
Connection conn = null;
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/jsp_db?useUnicode=true&characterEncoding=utf-8&autoReconnection=true&serverTimezone=Hongkong", "root", "root");
} catch (Exception e) {
e.printStackTrace();
}
return conn;
}
public static void closeResource(Connection conn, PreparedStatement ps) {
try {
if (conn != null) {
conn.close();
}
if (ps != null) {
ps.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
public static void closeResource(Connection conn, PreparedStatement ps, ResultSet rs) {
try {
if (conn != null) {
conn.close();
}
if (ps != null) {
ps.close();
}
if (rs != null) {
rs.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
3.BaseDAO.java
package com.jike.util;
import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
public class BaseDAO {
public static ArrayList getList(Class cl) {
ArrayList aList = new ArrayList<>();
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
String sql = "select * from tb_" + cl.getSimpleName();
System.out.println(sql);
Field[] flist = cl.getDeclaredFields();
try {
conn = BaseConnection.getConnection();
ps = conn.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()) {
Object obj = cl.newInstance();
for (Field f : flist) {
f.setAccessible(true);
f.set(obj, rs.getObject(f.getName()));
}
aList.add(obj);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
BaseConnection.closeResource(conn, ps, rs);
}
return aList;
}
public static boolean insert(Object obj) {
boolean b = false;
Connection conn = null;
PreparedStatement ps = null;
Class cl = obj.getClass();
Field[] flist = cl.getDeclaredFields();
List<String> fieldAList = new ArrayList<>();
List<String> paramAList = new ArrayList<>();
for (int i = 1; i < flist.length; i++) {
fieldAList.add(flist[i].getName());
paramAList.add("?");
}
StringBuffer sb = new StringBuffer();
sb.append(" insert into tb_" + cl.getSimpleName() + "(" + String.join(",", fieldAList) + ")");
sb.append(" values(" + String.join(",", paramAList) + ");");
System.out.println(sb.toString());
try {
conn = BaseConnection.getConnection();
ps = conn.prepareStatement(sb.toString());
for (int i = 1; i < flist.length; i++) {
flist[i].setAccessible(true);
ps.setObject(i, flist[i].get(obj));
}
int n = ps.executeUpdate();
if (n > 0) {
b = true;
}
} catch (Exception e) {
e.printStackTrace();
} finally {
BaseConnection.closeResource(conn, ps);
}
return b;
}
public static boolean update(Object obj) {
boolean b = false;
Connection conn = null;
PreparedStatement ps = null;
Class cl = obj.getClass();
Field[] flist = cl.getDeclaredFields();
ArrayList<String> fieldAList = new ArrayList<>();
for (int i = 1; i < flist.length; i++) {
fieldAList.add(flist[i].getName() + "=?");
}
StringBuffer sql = new StringBuffer();
sql.append("update tb_" + cl.getSimpleName() + " set ");
sql.append(String.join(",", fieldAList));
sql.append(" where " + flist[0].getName() + "=" + "?;");
System.out.println(sql.toString());
try {
conn = BaseConnection.getConnection();
ps = conn.prepareStatement(sql.toString());
for (int i = 1; i < flist.length; i++) {
flist[i].setAccessible(true);
ps.setObject(i, flist[i].get(obj));
}
flist[0].setAccessible(true);
ps.setObject(flist.length, flist[0].get(obj));
int n = ps.executeUpdate();
if (n > 0) {
b = true;
}
} catch (Exception e) {
e.printStackTrace();
}
return b;
}
public static boolean delete(Object obj, int id) {
boolean b = false;
Connection conn = null;
PreparedStatement ps = null;
Class cl = obj.getClass();
Field[] flist = cl.getDeclaredFields();
StringBuffer sql = new StringBuffer();
sql.append("delete from tb_" + cl.getSimpleName());
sql.append(" where " + flist[0].getName() + "=?");
System.out.println(sql);
try {
conn = BaseConnection.getConnection();
ps = conn.prepareStatement(sql.toString());
flist[0].setAccessible(true);
ps.setObject(1,id);
int n = ps.executeUpdate();
if (n > 0) {
b = true;
}
} catch (Exception e) {
e.printStackTrace();
} finally {
BaseConnection.closeResource(conn, ps);
}
return b;
}
}
4.TestMain.java
package com.jike.main;
import java.util.ArrayList;
import com.jike.dao.UserDao;
import com.jike.entity.User;
import com.jike.util.BaseDAO;
public class TestMain {
public static void main(String[] args) {
/*
* ArrayList<User> list = UserDao.getList(); for (User u : list) {
* System.out.println("uId:" + u.getuId() + ",uName:" + u.getuAge()); }
*/
/*
* ArrayList<User> list =BaseDAO.getList(User.class); for (User u :
* list) { System.out.println("uId:" + u.getuId() + ",uName:" +
* u.getuAge()); }
*/
/*
* User u = new User(); u.setuName("Lusy"); u.setuAge(19);
* u.setClassId(3); boolean b = UserDao.insert(u);
* System.out.println(b);
*/
/*User u = new User();
u.setuName("Lusy");
u.setuAge(19);
u.setClassId(3);
boolean b = BaseDAO.insert(u);
System.out.println(b);*/
/*User u = new User();
u.setuName("Lusy");
u.setuAge(19);
u.setClassId(3);
u.setuId(8);
boolean b = BaseDAO.update(u);
System.out.println(b);*/
User u = new User();
boolean b = BaseDAO.delete(u,11);
System.out.println(b);
}
}