使用 FreeMarker ＋ JdbcTemplate 生成Java Bean
其实就是代码生成
这次我列举一个简单的，生成mysql对应表的Java Bean
1、建表
CREATE TABLE `user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`userName` varchar(45) DEFAULT NULL,
`birthday` date DEFAULT NULL,
`gender` tinyint(2) DEFAULT 1,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
2、搭建一个能调用Spring JdbcTemplate的工程
…忽略
3、代码实现生成Java Bean
GenerateDomainFromTable.java
package com.denghb.duanzi.toolkit;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.denghb.duanzi.tools.StringTools;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import com.denghb.duanzi.domain.TableInfo;
import freemarker.template.Configuration;
import freemarker.template.DefaultObjectWrapper;
import freemarker.template.Template;
import freemarker.template.TemplateException;
/**
* Hello world!
*
*/
public class GenerateDomainFromTable {
public static void main(String[] args) {
ApplicationContext app = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");
JdbcTemplate jdbcTemplate = app.getBean(JdbcTemplate.class);
String databaseName = "duanzi";
String tableName = "user";
String domainName = StringTools.firstCharToUpperCase(tableName);
// 查询对应数据库对应表的字段信息
String sql = "SELECT * FROM information_schema.COLUMNS WHERE table_name = ? AND table_schema = ?;";
List<TableInfo> list = jdbcTemplate.query(sql, BeanPropertyRowMapper.newInstance(TableInfo.class),tableName,databaseName);
System.out.println(list.toString());
Configuration config = new Configuration();
try {
String path = new File("").getAbsolutePath();
config.setDirectoryForTemplateLoading(new File(path));
config.setObjectWrapper(new DefaultObjectWrapper());
Template template = config.getTemplate("domain.ftl", "UTF-8");
// 创建数据模型
Map<String,Object> root = new HashMap<String,Object>();
root.put("list", list);
root.put("domainName", domainName);
root.put("isDateType",true);// 实现方式待优化
File file = new File(domainName+".java");
if (!file.exists()) {
// System.out.println("file exist");
file.createNewFile();
}
Writer out = new BufferedWriter(new FileWriter(file));
template.process(root, out);
out.flush();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (TemplateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
TableInfo.java
package com.denghb.duanzi.domain;
import com.denghb.duanzi.tools.StringTools;
import org.apache.commons.lang.StringUtils;
import java.io.Serializable;
public class TableInfo implements Serializable {
private static final long serialVersionUID = 1L;
private String columnName;
private String dataType;
private String columnComment;
// 大写对象名称
private String objectName;
public String getColumnName() {
return columnName;
}
public void setColumnName(String columnName) {
this.columnName = columnName;
}
public String getDataType() {
return StringTools.databaseTypeToJavaType(dataType);
}
public void setDataType(String dataType) {
this.dataType = dataType;
}
public String getColumnComment() {
return columnComment;
}
public void setColumnComment(String columnComment) {
this.columnComment = columnComment;
}
public String getObjectName() {
return StringTools.firstCharToUpperCase(this.columnName);
}
public void setObjectName(String objectName) {
this.objectName = objectName;
}
@Override
public String toString() {
return "TableInfo [columnName=" + columnName + ", dataType=" + dataType + ", columnComment=" + columnComment + "]";
}
}
模版
domain.ftl
package com.denghb.duanzi.domain;
import java.io.Serializable;
<#if isDateType >
import java.util.Date;
</#if>
/**
*
*/
public class ${domainName} implements Serializable {
private static final long serialVersionUID = 1L;
<#list list as table>
/** ${table.columnComment} */
private ${table.dataType} ${table.columnName};
</#list>
<#list list as table>
public ${table.dataType} get${table.objectName}(){
return ${table.columnName};
}
public void set${table.objectName}(${table.dataType} ${table.columnName}){
this.${table.columnName} = ${table.columnName};
}
</#list>
@Override
public String toString(){
return "${domainName} [<#list list as table>${table.columnName}=" + ${table.columnName} +",</#list>]";
}
}
StringTools.java
package com.denghb.duanzi.tools;
import org.apache.commons.lang.StringUtils;
/**
* Created by denghb on 15/11/13.
*/
public class StringTools {
/**
* 字符串第一个字符转大写
* @param string
* @return
*/
public static String firstCharToUpperCase(String string){
if(StringUtils.isNotBlank(string)){
int length = string.length();
// 获取第一个转大写
String first = string.substring(0,1);
first = first.toUpperCase();
// 判断字符长度
if(1 == length){
return first;
}
String other = string.substring(1, length);
return first+other;
}
return string;
}
/**
* 数据库类型转java类型
* TODO 待完善
* @param dataType
* @return
*/
public static String databaseTypeToJavaType(String dataType) {
if (StringUtils.isNotBlank(dataType)) {
dataType = dataType.toLowerCase().trim();
if ("varchar".equals(dataType) || "text".equals(dataType) || "string".equals(dataType)) {
dataType = "String";
} else if ("int".equals(dataType) || "integer".equals(dataType)) {
dataType = "Integer";
} else if ("bigint".equals(dataType) || "long".equals(dataType)) {
dataType = "Long";
} else if ("timestamp".equals(dataType) || "datetime".equals(dataType) || "date".equals(dataType)) {
dataType = "Date";
} else if ("tinyint".equals(dataType) || "boolean".equals(dataType)) {
dataType = "Boolean";
} else {
throw new RuntimeException("dataType not find :" + dataType);
}
return dataType;
}
return null;
}
}
运行后结果
User.java
package com.denghb.duanzi.domain;
import java.io.Serializable;
import java.util.Date;
/**
*
*/
public class User implements Serializable {
private static final long serialVersionUID = 1L;
/** ID */
private Integer id;
/** 用户名 */
private String userName;
/** 生日 */
private Date birthday;
/** 性别 */
private Boolean gender;
public Integer getId(){
return id;
}
public void setId(Integer id){
this.id = id;
}
public String getUserName(){
return userName;
}
public void setUserName(String userName){
this.userName = userName;
}
public Date getBirthday(){
return birthday;
}
public void setBirthday(Date birthday){
this.birthday = birthday;
}
public Boolean getGender(){
return gender;
}
public void setGender(Boolean gender){
this.gender = gender;
}
@Override
public String toString(){
return "User [id=" + id +",userName=" + userName +",birthday=" + birthday +",gender=" + gender +",]";
}
}
是不是很简单呢？
：）
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