JDBC MySQL UTF-8字符串写入问题 [英] JDBC MySQL UTF-8 string writing problem

问题描述

连接到db：

public DBSource(ConnectionInfo ci) throws
        ClassNotFoundException, InstantiationException,
        IllegalAccessException, SQLException
{
    Class.forName("com.mysql.jdbc.Driver").newInstance();
    String dbPath = String.format(
        "jdbc:mysql://%s:%d/%s?user=%s&password=%s&characterEncoding=utf-8&" + 
        "useUnicode=true", ci.host, ci.port, ci.dbName, ci.user, ci.password);
    conn = java.sql.DriverManager.getConnection(dbPath);
    prepareTables();
}

表创建代码：

private void prepareTables() throws SQLException
{
    java.sql.Statement stat = conn.createStatement();

    String query = "set names utf8";
    stat.execute(query);

    query = "set character set utf8";
    stat.execute(query);

    query = "show variables like '%char%'";
    stat.execute(query);
    java.sql.ResultSet rs = stat.getResultSet();
    while (rs.next())
    {
        String k = rs.getString(1);
        String v = rs.getString(2);
        System.out.println(k + " - " + v);
    }

    query = "drop table if exists clt";
    stat.execute(query);
    query = "create table clt"
            + "("
            + "  id bigint not null"
            + ", text varchar(50) not null"
            + ") default character set utf8";
    stat.execute(query);
}

行插入：

public void visit(Insert i) throws SQLException
{
    String query = "insert into clt"
            + " (id, text) values (?, ?)";
    java.sql.PreparedStatement stmt = conn.prepareStatement(query);
    if (i.rowData.id == 12656697)
    {
        String toOut = "<<< " + Long.toString(i.rowData.id) + " - " + i.rowData.text;
        System.out.println(toOut);
    }
    int it = 0;
    stmt.setLong(++it, i.rowData.id);
    stmt.setString(++it, i.rowData.text);
    stmt.execute();
    stmt.close();
}

检查数据：

 public void checkText() throws SQLException
{
    java.sql.Statement stmt = conn.createStatement();
    String query = "select id, text from clt where id = '12656697'";
    stmt.execute(query);
    java.sql.ResultSet rs = stmt.getResultSet();
    while (rs.next())
    {
        String k = rs.getString(1);
        String v = rs.getString(2);
        String toOut = ">>> " + k + " - " + v;
        System.out.println(toOut);
    }
}

输出：

character_set_client - utf8
character_set_connection - latin1
character_set_database - latin1
character_set_filesystem - binary
character_set_results - utf8
character_set_server - utf8
character_set_system - utf8
character_sets_dir - /usr/share/mysql/charsets/

<<< 12656697 - Апарати
>>> 12656697 - ???????

问题：在表格中我有 ???? ??????? 文本字段中的符号。

Problem: In table I have "???????????" symbols at the text field.

预期字符串：Апарати

结果： ???????

这是一些那种魔法

我解决了一个问题......但是如果smbd会向我解释，我们仍然会感激。

所以。

It is some kind of magic
I resolved an issue... But still will appreciate if smbd will explain it to me.
So.

1. 我添加到我的/etc/mysql/my.cnf由Costis Aivalis建议的行
   
   
   结果相同


2. 我从代码中删除了行：
   
   query =set character set utf8;
   
   stat.execute（query）;

它正在运行!!! ：）

推荐答案

确保正确定义了MySQL配置编码。使用以下命令检查您的设置和修改的正确性：

Ensure that your MySQL configuration encoding is defined correctly. Check your settings and the correctness of the modifications with these commands:

show variables like 'character%';

和显示'collat​​ion％'等变量;

将这些行添加到 my.cnf 或 my.ini ：

对于MySQL 5.1.nn和更高版本5.5.29，您只需要这两行：

For MySQL 5.1.nn, and later versions 5.5.29 you just need these two lines:

[mysqld]
character-set-server = utf8
character-set-filesystem = utf8

对于MySQL 5.0.nn及更早版本使用这些设置：

For MySQL 5.0.nn and older use these settings:

[client]
default-character-set=utf8

[mysql]
default-character-set=utf8

[mysqld]
default-character-set=utf8
character-set-server=utf8

使用 MySQL-Workbench 用于您的设置。版本5+非常好。

It is probably more convenient to use MySQL-Workbench for your settings. Versions 5+ are excellent.

在你的Java程序中连接如下：

In your Java program connect like this:

con = DriverManager.getConnection("jdbc:mysql://localhost:3306/myDatabase?useUnicode=true&characterEncoding=UTF-8","user","passwd");

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