1 package schiller.com;
2
3 import java.sql.*;
4
5 public class Dbutils {
6 private String driver = "com.mysql.cj.jdbc.Driver";
7 private String user = "root";
8 private String password = "0000";
9 private String url =
10 "jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=Asia/Shanghai";
11
12 private static Connection conn = null;
13
14 // 获取数据库连接
15 public Connection getConnection() {
16 try {
17 Class.forName(driver);
18 conn = DriverManager.getConnection(this.url, this.user, this.password);
19 } catch (ClassNotFoundException e) {
20 e.printStackTrace();
21 } catch (SQLException e) {
22 e.printStackTrace();
23 }
24 return conn;
25 }
26
27 // 查询某条记录
28 public void selectById(String table, int id) {
29 try {
30 PreparedStatement pst =
31 conn.prepareStatement(String.format("select * from %s where id = %d", table, id));
32 ResultSet rs = pst.executeQuery();
33 while (rs.next()) {
34 String name = rs.getString(1);
35 int idd = rs.getInt(2);
36 String sex = rs.getString(3);
37 System.out.println(idd + " " + name + " " + sex);
38 }
39 rs.close();
40 pst.close();
41 } catch (SQLException e) {
42 e.printStackTrace();
43 }
44 }
45
46 // 查询全部记录
47 public void selectAll(String table) {
48 try {
49 PreparedStatement pst = conn.prepareStatement(String.format("select * from %s", table));
50 ResultSet rs = pst.executeQuery();
51 while (rs.next()) {
52 String name = rs.getString(1);
53 int idd = rs.getInt(2);
54 String sex = rs.getString(3);
55 System.out.println(idd + " " + name + " " + sex);
56 }
57 rs.close();
58 pst.close();
59 } catch (SQLException e) {
60 e.printStackTrace();
61 }
62 }
63
64 // 插入一条记录
65 public void insert(String table, String name, String sex) {
66 try {
67 PreparedStatement pst =
68 conn.prepareStatement(
69 String.format("insert into %s (name,sex) values ('%s', '%s')", table, name, sex));
70 int num = pst.executeUpdate();
71 if (num > 0) {
72 System.out.println("成功添加一条记录");
73 } else {
74 System.out.println("错误");
75 }
76 pst.close();
77 } catch (SQLException e) {
78 e.printStackTrace();
79 }
80 }
81
82 // 删除一条记录
83 public void deleleById(String table, int id) {
84 try {
85 PreparedStatement pst =
86 conn.prepareStatement(String.format("delete from %s where id = %d", table, id));
87 int num = pst.executeUpdate();
88 if (num > 0) {
89 System.out.println("成功删除一条记录");
90 } else {
91 System.out.println("错误");
92 }
93 pst.close();
94 } catch (SQLException e) {
95 e.printStackTrace();
96 }
97 }
98
99 // 更新某条记录
100 public void update(String table, String name, int id, String sex) {
101 try {
102 PreparedStatement pst =
103 conn.prepareStatement(
104 String.format("update %s set name='%s',sex='%s' where id=%d", table, name, sex, id));
105 int num = pst.executeUpdate();
106 if (num > 0) {
107 System.out.println("成功更新一条记录");
108 } else {
109 System.out.println("错误");
110 }
111 pst.close();
112 } catch (SQLException e) {
113 e.printStackTrace();
114 }
115 }
116 }
