基于Oracle的jdbc增删查改

oracle建表

pom.xml(个人版，请读者导入自己的依赖)：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.changping.jdbcdemo</groupId>
  <artifactId>jdbcdemo</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <dependencies>
        <dependency>
            <groupId>oracle</groupId>
            <artifactId>ojdbc6-connector-java</artifactId>
            <version>10.2.0.1.0</version>
        </dependency>
  </dependencies>
</project>

User.java(实体类)

package com.changping.jdbc.pojo;
public class User {
    private String userid;
    private String userpass;
    private String username;
    private String db_source;
    public String getUserid() {
        return userid;
    }
    public void setUserid(String userid) {
        this.userid = userid;
    }
    public String getUserpass() {
        return userpass;
    }
    public void setUserpass(String userpass) {
        this.userpass = userpass;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getDb_source() {
        return db_source;
    }
    public void setDb_source(String db_source) {
        this.db_source = db_source;
    }
    @Override
    public String toString() {
        return "User [userid=" + userid + ", userpass=" + userpass + ", username=" + username + ", db_source="
                + db_source + "]";
    }
    public User(String userid, String userpass, String username, String db_source) {
        super();
        this.userid = userid;
        this.userpass = userpass;
        this.username = username;
        this.db_source = db_source;
    }
    public User(String userpass, String username, String db_source) {
        super();
        this.userpass = userpass;
        this.username = username;
        this.db_source = db_source;
    }
    public User() {
        super();
    }
}

Add_User_Dao.java（增）

package com.changping.jdbc.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import com.changping.jdbc.pojo.User;
public class Add_User_Dao {
    /**
     * 1.增
     * 
     * @param user
     * @return
     */
    public int add_User(User user) {
        // 声明计数器
        int result = 0;
        // 1声明jdbc对象
        Connection conn = null;
        PreparedStatement pstmt = null;
        // 2加载驱动
        try {
            Class.forName("oracle.jdbc.driver.OracleDriver");
            // 3声明连接信息
            String url = "jdbc:oracle:thin:@localhost:1521:ORCL";
            String username = "scott";
            String password = "tiger";
            // 4建立连接
            try {
                conn = DriverManager.getConnection(url, username, password);
                // 5声明sql语句
                String sql = "insert into db_user (userid,userpass,username,db_source) values (seq_new_user.nextval,?,?,?)";
                // 6执行预编译sql，给参数赋值
                pstmt = conn.prepareStatement(sql);
                pstmt.setObject(1, user.getUserpass());
                pstmt.setObject(2, user.getUsername());
                pstmt.setObject(3, user.getDb_source());
                // 7执行sql,返回受影响的条目数
                result = pstmt.executeUpdate();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } finally {
            try {
                if (pstmt != null) {
                    pstmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return result;
    }
}

User_Add_Test.java(每一步都写一个测试类)

package com.changping.jdbc.test;
import com.changping.jdbc.dao.Add_User_Dao;
import com.changping.jdbc.pojo.User;
public class User_Add_Test {
    public static void main(String[] args) {
        Add_User_Dao userDao = new Add_User_Dao();
        User user = new User("123","tom","db_oracle_0424");//三参构造
        int result = userDao.add_User(user);//return 1
        System.out.println(result);
    }
}

Delete_User_Dao.java（删）

package com.changping.jdbc.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
public class Delete_User_Dao {
    /**
     * 2.通过姓名删除
     * 
     * @param username
     * @return
     */
    public int delete_user_by_username(String username) {
        int result = 0;
        // 1.声明jdbc对象
        Connection conn = null;
        PreparedStatement pstmt = null;
        // 2加载驱动
        try {
            Class.forName("oracle.jdbc.driver.OracleDriver");
            // 3声明连接信息
            String url = "jdbc:oracle:thin:@localhost:1521:ORCL";
            String user = "scott";
            String password = "tiger";
            // 4建立连接
            conn = DriverManager.getConnection(url, user, password);
            // 5声明sql语句
            String sql = "delete from db_user where username=?";
            // 6执行预编译sql，给参数赋值
            pstmt = conn.prepareStatement(sql);
            pstmt.setObject(1, username);
            // 7返回受影响的条目数
            result = pstmt.executeUpdate();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (conn != null) {
                    conn.close();
                }
                if (pstmt != null) {
                    pstmt.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        return result;
    }
}

User_Delete_Test.java

package com.changping.jdbc.test;
import com.changping.jdbc.dao.Delete_User_Dao;
public class User_Delete_Test {
    public static void main(String[] args) {
        Delete_User_Dao userDao = new Delete_User_Dao();
        int result = userDao.delete_user_by_username("tom");
        System.out.println(result);
    }
}

Find_User_Dao.java（条件查）

package com.changping.jdbc.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;
public class Find_User_Dao {
    /**
     * 3.根据姓名查询
     * 
     * @param username
     * @return
     */
    public Map<String, Object> find_User(String username) {
        Map<String, Object> user_map = new HashMap<String, Object>();
        // 1声明jdbc对象
        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        // 2加载驱动
        try {
            Class.forName("oracle.jdbc.driver.OracleDriver");
            // 3声明连接信息
            String url = "jdbc:oracle:thin:@localhost:1521:ORCL";
            String user = "scott";
            String password = "tiger";
            // 4建立连接
            try {
                conn = DriverManager.getConnection(url, user, password);
                // 5声明sql语句
                String sql = "select * from db_user where username = ?";
                // 6执行预编译sql，给参数赋值
                pstmt = conn.prepareStatement(sql);
                pstmt.setObject(1, username);
                // 7返回结果集信息
                rs = pstmt.executeQuery();
                // 8得到结果集元数据——方法的集合体，返回有column相关的一切信息
                ResultSetMetaData rsmd = rs.getMetaData();
                // 9从元数据类中返回结果集的列数
                int columnCount = rsmd.getColumnCount();
                // 10根据元数据里的列信息,得到每一列的字段名
                if (rs.next()) {
                    for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) {
                        String columnName = rsmd.getColumnName(columnIndex);// 根据对应列，返回列名
                        Object value = rs.getObject(columnName);// 根据列名返回该列所有值
                        user_map.put(columnName, value);
                    }
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) {
                    rs.close();
                }
                if (pstmt != null) {
                    pstmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        return user_map;
    }
}

User_Find_by_Name_Test.java

package com.changping.jdbc.test;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import com.changping.jdbc.dao.Find_User_Dao;
public class User_Find_by_Name_Test {
    public static void main(String[] args) {
        Find_User_Dao userDao = new Find_User_Dao();
        Map<String, Object> user_map = userDao.find_User("tom");

        //1、foreach遍历
        Set<Entry<String, Object>> entryset = (Set<Entry<String, Object>>) user_map.entrySet();
        for (Entry<String, Object> entry : entryset) {
            System.out.println(entry.getKey() + " : " + entry.getValue());
        }

        System.out.println("------------------------------------------");
        
        //2、迭代遍历
        Set<String> keyset = user_map.keySet();
        Iterator<String> it = keyset.iterator();
        while (it.hasNext()) {
            System.out.println(user_map.get(it.next()));
        }

        System.out.println("------------------------------------------");

        //3、map转entryset转list,转的真正含义是换个数据结构装数据
        Set<Entry<String, Object>> set = user_map.entrySet();
        Iterator<Entry<String, Object>> iteratory = set.iterator();
        List<Object> list = new ArrayList<Object>();
        while (iteratory.hasNext()) {
            Entry<String, Object> entry = iteratory.next();
            list.add(entry.getKey());
            list.add(entry.getValue());
        }
        System.out.println(list);
    }
}

Query_User_Dao.java（全查）

package com.changping.jdbc.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class Query_User_Dao {
    /**
     * 4.查全部
     * 
     * @return
     */
    public List<Map<String, Object>> queryUser() {
        List<Map<String, Object>> list_user = new ArrayList<Map<String, Object>>();
        // 1声明jdbc对象
        Connection conn = null;
        PreparedStatement pstmt = null;
        ResultSet rs = null;
        // 2加载驱动
        try {
            Class.forName("oracle.jdbc.driver.OracleDriver");
            // 3声明连接信息
            String url = "jdbc:oracle:thin:@localhost:1521:ORCL";
            String username = "scott";
            String password = "tiger";
            // 4建立连接
            try {
                conn = DriverManager.getConnection(url, username, password);
                // 5声明sql语句
                String sql = "select * from db_user";
                // 6声明预编译对象
                pstmt = conn.prepareStatement(sql);
                // 7返回resultset结果集
                rs = pstmt.executeQuery();
                // 8得到结果集元数据——方法的集合体，返回有column相关的一切信息
                ResultSetMetaData rsmd = rs.getMetaData();
                // 9得到结果集总列数
                int columnCount = rsmd.getColumnCount();
                // 10通过结果集列数进行遍历
                while (rs.next()) {
                    Map<String, Object> map = new HashMap<String, Object>();
                    // 遍历每一列并放入map中
                    for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) {
                        String columnName = rsmd.getColumnName(columnIndex);
                        Object value = rs.getObject(columnName);
                        map.put(columnName, value);
                    }
                    list_user.add(map);
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) {
                    rs.close();
                }
                if (pstmt != null) {
                    pstmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return list_user;
    }
}

User_Query_Test.java

package com.changping.jdbc.test;
import java.util.List;
import java.util.Map;
import com.changping.jdbc.dao.Query_User_Dao;
public class User_Query_Test {
    public static void main(String[] args) {
        Query_User_Dao userDao = new Query_User_Dao();
        List<Map<String,Object>> user_list = userDao.queryUser();
        System.out.println(user_list);
    }
}

Update_User_Dao.java（改）

package com.changping.jdbc.dao;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import com.changping.jdbc.pojo.User;
public class Update_User_Dao {
    /**
     * 5.通过姓名修改
     * 
     * @param user
     * @return
     */
    public int update_user_by_username(User user) {
        int result = 0;
        // 1声明jdbc对象
        Connection conn = null;
        PreparedStatement pstmt = null;
        // 2加载驱动
        try {
            Class.forName("oracle.jdbc.driver.OracleDriver");
            // 3声明连接信息
            String url = "jdbc:oracle:thin:@localhost:1521:ORCL";
            String username = "scott";
            String password = "tiger";
            // 4建立连接
            try {
                conn = DriverManager.getConnection(url, username, password);
                // 5声明sql语句
                String sql = "update db_user set userpass=?,db_source=? where username=?";
                // 6执行预编译sql，给参数赋值
                pstmt = conn.prepareStatement(sql);
                pstmt.setObject(1, user.getUserpass());
                pstmt.setObject(2, user.getDb_source());
                pstmt.setObject(3, user.getUsername());
                // 7返回受影响的条目数
                result = pstmt.executeUpdate();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } finally {
            try {
                if (pstmt != null) {
                    pstmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        return result;
    }
}

User_Update_Test.java

package com.changping.jdbc.test;
import com.changping.jdbc.dao.Update_User_Dao;
import com.changping.jdbc.pojo.User;
public class User_Update_Test {
    public static void main(String [] args)
    {
        Update_User_Dao userDao = new Update_User_Dao();
        User user = new User();
        user.setDb_source("db0425");
        user.setUserpass("123");
        user.setUsername("tom");
        int result = userDao.update_user_by_username(user);
        System.out.println(result);
    }
}

如果用Mysql数据库，驱动、连接信息需修改如下：

            Class.forName("com.mysql.jdbc.Driver");
            String url = "jdbc:mysql://localhost:3306/db0325";
            String user ="root";
            String password = "root";