【手把手】JavaWeb 入门级项目实战 -- 文章发布系统 （第五节）

db.username=root
db.password=
db.dataBaseName=article

package test;
/**
 * 读取Properties文件的测试类
 * @author 剽悍一小兔
 */
public class TestProperties {
    public static void main(String[] args) {
        
    }
}

InputStream inputStream =  TestProperties.class.getClassLoader().getResourceAsStream("jdbc.properties");
Properties p = new Properties();
try {
    p.load(inputStream);
    System.out.println(p);
} catch (IOException e) {
    e.printStackTrace();
}

InputStream inputStream =  TestProperties.class.getClassLoader().getResourceAsStream("jdbc.properties");

p.load(inputStream);

 System.out.println(p);

System.out.println(p.getProperty("db.username"));
System.out.println(p.getProperty("db.password"));
System.out.println(p.getProperty("db.dataBaseName"));

private static String username; //用户名
private static String password; //密码
private static String dataBaseName; //数据库名

/**
 * 配置数据库的基本信息
 * @return void
 */
public static void config(String path){
    InputStream inputStream = DataBaseUtils.class.getClassLoader().getResourceAsStream(path);
    Properties p = new Properties();
    try {
        p.load(inputStream);
        username = p.getProperty("db.username");
        password = p.getProperty("db.password");
        dataBaseName = p.getProperty("db.dataBaseName");
    } catch (IOException e) {
        e.printStackTrace();
    }
}

static {
    config("jdbc.properties");
}

/**
 * 获取数据库链接
 * @return Connection 
 */
public static Connection getConnection(){
    Connection connection = null;
    try {
        Class.forName("com.mysql.jdbc.Driver");
        connection  = DriverManager.getConnection("jdbc:mysql://localhost:3306/"+dataBaseName+"?useUnicode=true&characterEncoding=utf8",username,password);
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    } catch (SQLException e) {
        e.printStackTrace();
    }
    return connection;
}

DataBaseUtils.config("jdbc.properties");
Connection conn = DataBaseUtils.getConnection();
System.out.println(conn);

/**
 * 关闭资源
 * @param connection
 * @param statement
 * @param rs
 */
public static void closeConnection(Connection connection,PreparedStatement statement,ResultSet rs){
    try {
        if(rs!=null)rs.close();
        if(statement!=null)statement.close();
        if(connection!=null)connection.close();
    } catch (Exception e) {
        e.fillInStackTrace();
    }
}

/**
 * DML操作
 * @param sql
 * @param objects
 */
public static void update(String sql,Object...objects){
    Connection connection = getConnection();
    PreparedStatement statement = null;
    try {
        statement = (PreparedStatement) connection.prepareStatement(sql);
        for (int i = 0; i < objects.length; i++) {
            statement.setObject(i+1, objects[i]);
        }
        statement.executeUpdate();
    } catch (SQLException e) {
        e.printStackTrace();
    }finally{
        closeConnection(connection, statement, null);
    }
}

String id = UUID.randomUUID() + "";
String createTime = new SimpleDateFormat("yyyy-MM-dd").format(new Date());
update("INSERT INTO t_user(id,username,password,sex,create_time,is_delete,address,telephone) "
        + "VALUES (?, ?, ?, ?, ?, ?, ?, ?)", id,"张三",123456,0,createTime,0,"保密","保密");

com.mysql.jdbc.MysqlDataTruncation: Data truncation: Data too long for column 'id' at row 1
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2983)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1631)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1723)
    at com.mysql.jdbc.Connection.execSQL(Connection.java:3283)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1332)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1604)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1519)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:1504)
    at util.DataBaseUtils.update(DataBaseUtils.java:147)
    at util.DataBaseUtils.main(DataBaseUtils.java:165)

Data truncation: Data too long for column 'id' at row 1

public static String getCreateTableSQl(Class<?> clazz){
    StringBuilder sb = new StringBuilder();
    
    //获取表名
    Table table = (Table) clazz.getAnnotation(Table.class);
    String tableName = table.tableName();
    sb.append("DROP TABLE IF EXISTS ").append(tableName).append(";\n");
    sb.append("create table ");
    sb.append(tableName).append("(\n");
    
    Field[] fields = clazz.getDeclaredFields();
    String primaryKey = "";
    //遍历所有字段
    for (int i = 0; i < fields.length; i++) {
        Column column = (Column) fields[i].getAnnotations()[0];
        String field = column.field();
        String type = column.type();
        boolean defaultNull = column.defaultNull();
        
        sb.append("\t" + field).append(" ").append(type);
        if(defaultNull){
            if(type.toUpperCase().equals("TIMESTAMP")){
                sb.append(",\n");
            }else{
                sb.append(" DEFAULT NULL,\n");
            }
        }else{
            sb.append(" NOT NULL,\n");
            if(column.primaryKey()){
                primaryKey = "PRIMARY KEY ("+field+")";
            }
        }
    }
    
    if(!StringUtils.isEmpty(primaryKey)){
        sb.append("\t").append(primaryKey);
    }
    sb.append("\n) DEFAULT CHARSET=utf8");
    
    return sb.toString();
}

String sql = TableUtils.getCreateTableSQl(User.class);
System.out.println(sql);

String id = UUID.randomUUID() + "";
String createTime = new SimpleDateFormat("yyyy-MM-dd").format(new Date());
update("INSERT INTO t_user(id,username,password,sex,create_time,is_delete,address,telephone) "
        + "VALUES (?, ?, ?, ?, ?, ?, ?, ?)", id,"张三",123456,0,createTime,0,"保密","保密");