将数据库表转为POJO-白红宇

第一步：连接数据库

                               
import
java.sql.Connection;
import
java.sql.DriverManager;
import
java.sql.ResultSet;
import
java.sql.SQLException;
import
java.sql.Statement;
import
javax.swing.JOptionPane;
public
class
DBConnection { 
private
static
final
String DBDRIVER = 
"com.mysql.jdbc.Driver"
;                 
//驱动类类名
private
static
final
String DBURL = 
"jdbc:mysql://localhost:3306/ibatis"
;       //连接URL
private
static
final
String DBUSER = 
"root"
;                                    
//数据库用户名
private
static
final
String DBPASSWORD = 
"admin"
;                               
//数据库密码
static
{                                                                         
//将加载驱动放到静态块中
try
{ 
Class.forName(DBDRIVER);                                                
//加载驱动
} 
catch
(ClassNotFoundException e1) {                                       
//发生加载驱动异常
JOptionPane.showMessageDialog(
null
,
"加载驱动失败!!!"
,
"提示信息"
,
JOptionPane.INFORMATION_MESSAGE);                               
//提示加载驱动失败
}
}
public
static
Connection getConnection() { 
Connection conn = 
null
;                                                     
//建立Connection接口引用
try
{ 
conn = DriverManager.getConnection(DBURL, DBUSER, DBPASSWORD);          
//建立连接
} 
catch
(SQLException e) {                                                  
// 发生连接异常
JOptionPane.showMessageDialog(
null
,
"连接MySQL连接失败！！！"
,
"提示信息"
,
JOptionPane.INFORMATION_MESSAGE);                               
//提示连接MySQL连接失败
}
return
conn;
}
public
static
void
close(Connection conn) { 
if
(conn != 
null
) {                                                         
//判断Connection对象是否为空
try
{ 
conn.close();                                                       
// 关闭连接数据库资源
} 
catch
(SQLException e){                                               
//判断关闭Connection对象时是否发生异常
System.out.println(
"关闭数据库连接发生异常"
);
}
}
}
public
static
void
close(Statement stmt) { 
if
(stmt != 
null
){                                                          
//判断Statement对象是否为空
try
{ 
stmt.close();                                                       
//关闭操作数据库资源
} 
catch
(SQLException e){                                               
//判断关闭Statement对象时是否发生异常
JOptionPane.showMessageDialog(
null
,
"关闭数据库操作资源发生异常！！！"
,
"提示信息"
,
JOptionPane.INFORMATION_MESSAGE);                           
//提示关闭数据库操作资源发生异常
}
}
}
public
static
void
close(ResultSet rs) { 
if
(rs != 
null
) {                                                           
//判断结果集是否为空
try
{ 
rs.close();                                                         
//关闭结果集
} 
catch
(SQLException e){                                               
//判断结果集是否发生异常
JOptionPane.showMessageDialog(
null
,
"关闭结果集发生异常！！！"
,
"提示信息"
,
JOptionPane.INFORMATION_MESSAGE);                           
//提示关闭结果集发生异常
}
}
}
}
          
        

第二步：执行转换：

                               
import
java.io.File;
import
java.io.PrintWriter;
import
java.sql.Connection;
import
java.sql.DatabaseMetaData;
import
java.sql.PreparedStatement;
import
java.sql.ResultSet;
import
java.sql.ResultSetMetaData;
import
java.sql.Types;
import
org.apache.commons.dbutils.DbUtils;
public
class
BuildDTO { 
public
void
build(String tableName, String packageName, String className) { 
Connection conn = 
null
;
PreparedStatement pment = 
null
;
ResultSet rs = 
null
;
PrintWriter pw = 
null
;
String pack = packageName.replace(
"."
, 
"/"
);
// 包名
System.out.println(
"src/"
+ pack + 
"/"
+ className + 
".java"
);
try
{ 
pw = 
new
PrintWriter(
new
File(
"src/"
+ pack + 
"/"
+ className
+ 
".java"
));
pw.println(
"package "
+ packageName + 
";\n\n"
);
pw.println(
""
);
pw.println(
"public class "
+ className + 
" \n{\t"
);
// 创建连接
conn = DBConnection.getConnection();
// 构建预处理器
pment = conn.prepareStatement(
"select * from "
+ tableName
+ 
" where 1 = 2;"
);
rs = pment.executeQuery();
ResultSetMetaData metaData = rs.getMetaData();
// 获取表单的列数
int
colum = metaData.getColumnCount();
for
(
int
i = 
1
; i <= colum; i++) { 
String pStr = 
""
; 
// setXxxx
String typeStr = 
""
; 
// 类型
// 获取列名
String columName = metaData.getColumnName(i);
// 获取每一列的数据类型
int
type = metaData.getColumnType(i);
// System.out.println(i+"---"+type);
// 判断
typeStr = type(type);
// 组装 private 的语句
pStr += 
"private "
+ typeStr + 
" "
+ columName + 
";"
;
// 输出 private 的字段
pw.println(
"\t"
+ pStr + 
""
);
}
String constructStr = 
""
; 
// 构造
// 组装空参构造
constructStr += 
"public "
+ className + 
"()\n\t{\n\n\t}"
;
// 输出空参构造
pw.println(
"\n\t"
+ constructStr + 
"\n"
);
for
(
int
i = 
1
; i <= colum; i++) { 
String getStr = 
""
;
String setStr = 
""
;
String typeStr = 
""
;
// 获取列名
String columName = metaData.getColumnName(i);
// 获取每一列的数据类型
int
type = metaData.getColumnType(i);
// 判断
typeStr = type(type);
// 组装 set 的语句
setStr += 
"public void set"
+ columName.substring(
0
, 
1
).toUpperCase() + 
""
+ columName.substring(
1
) + 
"("
+ typeStr + 
" "
+ columName + 
")\n\t{\n"
;
setStr += 
"\t\tthis."
+ columName + 
" = "
+ columName
+ 
";\n\t}"
;
// 组装get语句
getStr += 
"public "
+ typeStr + 
" get"
+ columName.substring(
0
, 
1
).toUpperCase() + 
""
+ columName.substring(
1
) + 
"()\n\t{\n\t"
;
getStr += 
"\treturn this."
+ columName + 
";\n\t}"
;
// 输出 set
pw.println(
"\t"
+ setStr);
// 输出 get
pw.println(
"\t"
+ getStr);
}
pw.println(
"}"
);
// 缓冲
pw.flush();
pw.close();
} 
catch
(Exception e) { 
e.printStackTrace();
} 
finally
{ 
// 关闭连接
DbUtils.closeQuietly(conn, pment, rs);
}
}
public
String type(
int
type) { 
String typeStr = 
null
;
if
(Types.INTEGER == type) { 
typeStr = 
"Integer"
;
} 
else
if
(Types.VARCHAR == type) { 
typeStr = 
"String"
;
} 
else
if
(Types.CHAR == type) { 
typeStr = 
"CHAR"
;
} 
else
if
(Types.TIMESTAMP == type) { 
typeStr = 
"Date"
;
} 
else
if
(Types.INTEGER == type) { 
typeStr = 
"Integer"
;
} 
else
if
(Types.LONGVARCHAR == type) { 
typeStr = 
"String"
;
}
return
typeStr;
}
//获取数据库中的所有表
public
void
getTableNameByCon(Connection con) { 
try
{ 
DatabaseMetaData meta = con.getMetaData();
ResultSet rs = meta.getTables(
null
, 
null
, 
null
,
new
String[] { 
"TABLE"
});
while
(rs.next()) { 
System.out.println(
"表名："
+ rs.getString(
3
));
System.out.println(
"表所属用户名："
+ rs.getString(
2
));
System.out.println(
"------------------------------"
);
}
con.close();
} 
catch
(Exception e) { 
try
{ 
con.close();
} 
catch
(Exception e1) { 
// TODO Auto-generated catch block
e1.printStackTrace();
}
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public
static
void
main(String[] args) { 
BuildDTO dto = 
new
BuildDTO();
dto.build(
"User"
, 
"com.mzsx.sql2bean"
, 
"User"
);
dto.getTableNameByCon(DBConnection.getConnection());
}
}
          
        

本文转自梦朝思夕 51CTO博客，原文链接:http://blog.51cto.com/qiangmzsx/1305085