摘要：做到每個敲下的按鍵每次鼠標(biāo)的點擊每次手機屏幕的觸碰，都能產(chǎn)生價值開發(fā)環(huán)境為了開發(fā)應(yīng)用級的程序，整個開發(fā)鏈比較繁瑣復(fù)雜，所以會需要更多的時間來掌握。注有關(guān)詳細(xì)信息請使用重新編譯。執(zhí)行文件執(zhí)行結(jié)果，打印表信息如下至此，與成功實現(xiàn)了數(shù)據(jù)交互。

ArthurSlog

SLog-5

Year·1

Guangzhou·China

July 11th 2018

做到每個敲下的按鍵、每次鼠標(biāo)的點擊、每次手機屏幕的觸碰，都能產(chǎn)生價值

Java為了開發(fā)應(yīng)用級的程序，整個開發(fā)鏈比較繁瑣復(fù)雜，所以會需要更多的時間來掌握。

老規(guī)則，讓我們明確一下需要的信息Mysql官方手冊

打開命令行，測試一下java，如果提示沒有安裝JDK，移步JavaJDK下載

安裝完JDK，測試一下安裝是否完整

java -version

java version "10.0.1" 2018-04-17
Java(TM) SE Runtime Environment 18.3 (build 10.0.1+10)
Java HotSpot(TM) 64-Bit Server VM 18.3 (build 10.0.1+10, mixed mode)

javac -version

javac 10.0.1

在macOS中，JDK安裝路徑是/Library/Java/JavaVirtualMachines/jdk-10.jdk/Contents/Home

在macOS中，JRE安裝路徑是/Library/Internet Plug-Ins/JavaAppletPlugin.plugin/Contents/Home

下載Connector / J，選擇platform Independent，選擇Platform Independent (Architecture Independent), ZIP Archive下載

下載好Connector / J后解壓文件得到文件夾，配置 CLASSPATH

export CLASSPATH=~/Downloads/mysql-connector-java-8.0.11.jar:$CLASSPATH

下面是完整代碼

LoadDriver.java

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;

// assume that conn is an already created JDBC connection (see previous examples)
public class LoadDriver {
    public static void main(String[] args) {
        try {
            // The newInstance() call is a work around for some
            // broken Java implementations

            Class.forName("com.mysql.cj.jdbc.Driver").newInstance();
            Connection conn = null;
            try {
                conn =
                DriverManager.getConnection("jdbc:mysql://localhost/my_db?" +
                "user=root&password=88888888");

                // Do something with the Connection

                Statement stmt = null;
                ResultSet rs = null;

                try {
                    stmt = conn.createStatement();
                    rs = stmt.executeQuery("SELECT * FROM Account");

                    // or alternatively, if you don"t know ahead of time that
                    // the query will be a SELECT...

                    if (stmt.execute("SELECT * FROM Account")) {
                        rs = stmt.getResultSet();
                    }

                    // Now do something with the ResultSet ....

                    ResultSetMetaData rsmd = rs.getMetaData();
                    int columnsNumber = rsmd.getColumnCount();
                    while (rs.next()) {
                        for (int i = 1; i <= columnsNumber; i++) {
                            if (i > 1) System.out.print(",  ");
                            String columnValue = rs.getString(i);
                            System.out.print(columnValue + " " + rsmd.getColumnName(i));
                        }
                        System.out.println("");
                    }
                }
                catch (SQLException ex){
                    // handle any errors
                    System.out.println("SQLException: " + ex.getMessage());
                    System.out.println("SQLState: " + ex.getSQLState());
                    System.out.println("VendorError: " + ex.getErrorCode());
                }
                finally {
                    // it is a good idea to release
                    // resources in a finally{} block
                    // in reverse-order of their creation
                    // if they are no-longer needed

                    if (rs != null) {
                        try {
                            rs.close();
                        } catch (SQLException sqlEx) { } // ignore

                        rs = null;
                    }

                    if (stmt != null) {
                        try {
                            stmt.close();
                        } catch (SQLException sqlEx) { } // ignore

                        stmt = null;
                    }
                }

            } catch (SQLException ex) {
                // handle any errors
                System.out.println("SQLException: " + ex.getMessage());
                System.out.println("SQLState: " + ex.getSQLState());
                System.out.println("VendorError: " + ex.getErrorCode());
            }
        } catch (Exception ex) {
            // handle the error
            System.out.println("Exception: " + ex.getMessage());
        }
    }
}

用java應(yīng)用程序注冊你的mysql jdbc驅(qū)動程序，參考Mysql/JDBC執(zhí)行SQL手冊

Class.forName("com.mysql.cj.jdbc.Driver").newInstance()

連接數(shù)據(jù)庫

conn =DriverManager.getConnection("jdbc:mysql://localhost/my_db?" + "user=root&password=88888888")

獲得連接對象，并執(zhí)行SQL指令

Statement stmt = null;
ResultSet rs = null;

stmt = conn.createStatement();
rs = stmt.executeQuery("SELECT * FROM Account");

獲得SQL執(zhí)行結(jié)果，對結(jié)果進行打印

ResultSetMetaData rsmd = rs.getMetaData();
int columnsNumber = rsmd.getColumnCount();
while (rs.next()) {
                    for (int i = 1; i <= columnsNumber; i++) {
                    if (i > 1) System.out.print(",  ");
                    String columnValue = rs.getString(i);
                    System.out.print(columnValue + " " + rsmd.getColumnName(i));
                    }
                    System.out.println("");
                    }

打印SQL結(jié)果

ResultSet resultSet = statement.executeQuery("SELECT * from foo");
ResultSetMetaData rsmd = resultSet.getMetaData();
int columnsNumber = rsmd.getColumnCount();
while (resultSet.next()) {
    for (int i = 1; i <= columnsNumber; i++) {
        if (i > 1) System.out.print(",  ");
        String columnValue = resultSet.getString(i);
        System.out.print(columnValue + " " + rsmd.getColumnName(i));
    }
    System.out.println("");
}

切換到LoadDriver.java文件路徑下，編譯LoadDriver.java文件

javac LoadDriver.java

編譯生成LoadDriver.class,編譯提示

注: LoadDriver.java使用或覆蓋了已過時的 API。
注: 有關(guān)詳細(xì)信息, 請使用 -Xlint:deprecation 重新編譯。

執(zhí)行LoadDriver.class文件

java LoadDriver

執(zhí)行結(jié)果，打印Account表信息如下：

1 ID,  ArthurSlog AccountName,  ArthurSlog Password

至此，Java與MySQL成功實現(xiàn)了數(shù)據(jù)交互。