知识大全 java程序操作MySQL数据库

Posted 2022-07-20 数据库

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java源代码（代码实现的是查询成绩为的人员信息至于其他功能的代码中有注释）注意在eclipse里运行程序的时候要工程里插入jar包否则运行异常！ import java sql *; import java io *; class database_manage public Connection conn = null; public ResultSet rs = null; private String DatabaseDriver = " mysql jdbc Driver"; // DataSource 数据源名称DSN private String DatabaseConnStr = "jdbc:mysql://localhost: /people_manage?useUnicode=true&characterEncoding=utf " + " root root"; public void setDatabaseDriver(String Driver) this DatabaseDriver = Driver; public String getDatabaseDriver() return (this DatabaseDriver); public void setDatabaseConnStr(String ConnStr) this DatabaseConnStr = ConnStr; public String getDatabaseConnStr() return (this DatabaseConnStr); public database_manage() // 构造函数连接数据库 try Class forName(DatabaseDriver); catch (java lang ClassNotFoundException e) System err println("加载驱动器有错误:" + e getMessage()); System out print("执行插入有错误:" + e getMessage());// 输出到客户端 public ResultSet query(String sql) // 查询数据库 rs = null; try conn = DriverManager getConnection( "jdbc:mysql://localhost: /people_manage?useUnicode=true&characterEncoding=utf " "root" "root"); Statement stmt = conn createStatement(); rs = stmt executeQuery(sql); catch (SQLException ex) System err println("执行查询有错误:" + ex getMessage()); System out print("执行查询有错误:" + ex getMessage()); // 输出到客户端

　　return rs;

public int update_database(String sql) // 更新或插入数据库 int num = ; try conn = DriverManager getConnection( "jdbc:mysql://localhost: /people_manage?useUnicode=true&characterEncoding=utf " "root" "root"); Statement stmt = conn createStatement(); num = stmt executeUpdate(sql); catch (SQLException ex) System err println("执行插入有错误:" + ex getMessage()); System out print("执行插入有错误:" + ex getMessage());// 输出到客户端　CloseDataBase(); return num; public void CloseDataBase() // 关闭数据库 try conn close(); catch (Exception end) System err println("执行关闭Connection对象有错误 " + end getMessage()); System out print("执行执行关闭Connection对象有错误有错误:" + end getMessage()); // 输出到客户端 class people private String uid; private String name; private String banji; private int score; public people() public people(String uid String name String banji) this uid = uid; this name = name; this banji = banji; public people(String uid String name String banji int score) this uid = uid; this name = name; this banji = banji; this score = score; public String getUid() return uid; public void setUid(String uid) this uid = uid; public String getName() return name; public void setName(String name) this name = name; public String getBanji() return banji; public void setBanji(String banji) this banji = banji; public int getScore() return score; public void setScore(int score) this score = score; public class manage private people[] people_array ;// 对象数组 public void add_people(String uid String name) 　String sql = "insert people (uid name) values ( " + uid + " " + name + " )";// sql插入语句 // String sql = "insert people (uid name) values ( uid tom )"; 　database_manage db_obj = new database_manage(); db_obj update_database(sql); public void update_people(String uid String name) 　String sql = "update people set name= " + name + " where uid= " + uid + " "; database_manage db_obj = new database_manage(); db_obj update_database(sql); public void delete_people(String uid) 　String sql = "delete from people where uid= " + uid + " "; 　database_manage db_obj = new database_manage(); 　db_obj update_database(sql); public people query_people(String uid) database_manage db_obj = new database_manage(); // String adminid=null; String uid_new name banji; uid_new = null; name = null; banji = null; String sql_query = "select * from people where uid= " + uid + " "; 　try ResultSet rs = db_obj query(sql_query); if (rs next()) uid_new = rs getString("uid"); name = rs getString("name"); banji = rs getString("banji"); catch (Exception e) e getMessage(); people new_people = new people(uid_new name banji); return new_people; public people[] query_people_byscore(int score) database_manage db_obj = new database_manage(); String uid_new name banji; uid_new = null; name = null; banji = null; int score_new = ;

　　String sql_query = "select * from people where score=" + score;// sql查询语句

　　try

　　ResultSet rs = db_obj query(sql_query);// 查询后返回结果集

　　int num = ;

　　ResultSet rs_new = rs;

　　while (rs_new next()) // 统计结果集中学生个数

　　num++;

　　// System out println(num);

　　people_array = new people[num];

　　int i = ;

　　rs beforeFirst();// 返回结果集的开始

　　while (rs next())

　　uid_new = rs getString("uid");

　　name = rs getString("name");

　　banji = rs getString("banji");

　　score_new = rs getInt("score");

　　people_array [i] = new people(uid_new name banji score_new);

　　i++;

　　 catch (Exception e)

　　e getMessage();

　　return people_array ;

　　public static void main(String args[])

　　* people new_people=new people();

　　* manage mr=new manage(); //mr add_people(" " "小明");插入一个学生的信息

　　* new_people=mr query_people(" ");//查询uid= 的学生信息返回对象 System out

　　* println(""+new_people getName()+"　 "+new_people getBanji());

　　* mr update_people(" " "小王");更新一个学生的信息

　　* new_people=mr query_people(" ");//更新后查询

　　* System out println(""+new_people getName()+"　 "+new_people getBanji(

　　* ));

　　manage mr = new manage();

　　// mr delete_people(" ");删除uid= 的学生信息

　　people[] people_array;// 声明对象数组

　　people_array = mr query_people_byscore( );// 返回成绩为一百的学生类数组后输出

　　int num = ;

　　num = people_array length;

　　for (int i = ; i < num; i++)

　　System out println(people_array[i] getUid() + " "

　　+ people_array[i] getName() + "　 "

　　+ people_array[i] getBanji() + "　 "

　　+ people_array[i] getScore());

> cha138/Article/program/Java/JSP/201311/20030