# Java-zzgc

**Repository Path**: whales-s/java-zzgc

## Basic Information

- **Project Name**: Java-zzgc
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2021-09-24
- **Last Updated**: 2021-09-29

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# 一、创建工程
    File--->New Project-->Java Enterprise--->Next...
# 二、后台代码

## 2、创建包

```xml
dao-----------操作数据库
entity--------与表对应的实体类
service-------业务逻辑包
servlet-------servlet包
utils---------工具类
```

## 3、引入依赖的jar包

```xml

<dependency>
    <groupId>javax.servlet</groupId>
    <artifactId>javax.servlet-api</artifactId>
    <version>4.0.1</version>
    <scope>provided</scope>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.26</version>
</dependency>
<dependency>
    <groupId>org.junit.jupiter</groupId>
    <artifactId>junit-jupiter-api</artifactId>
    <version>${junit.version}</version>
    <scope>test</scope>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.20</version>
</dependency>
<dependency>
    <groupId>log4j</groupId>
    <artifactId>log4j</artifactId>
    <version>1.2.17</version>
</dependency>
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.76</version>
</dependency>
```
## 4、创建数据库
```sql

DROP TABLE IF EXISTS user_info;

CREATE TABLE IF NOT EXISTS user_info
(
	user_id INT PRIMARY KEY AUTO_INCREMENT COMMENT '用户ID',
	user_name VARCHAR(255) NOT NULL COMMENT '用户名',
	user_pwd VARCHAR(255) NOT NULL COMMENT '密码',
	user_age INT DEFAULT 0 COMMENT '年龄',
	user_sex VARCHAR(4) DEFAULT '男' COMMENT '性别',
	create_time DATETIME DEFAULT NOW() COMMENT '创建时间',
	update_time DATETIME DEFAULT NOW() ON UPDATE NOW() COMMENT '更新时间',
	del_status INT DEFAULT 1 COMMENT '删除状态 1:未删除 0:删除'
);
-- 栏目
CREATE TABLE IF NOT EXISTS column_info
(
    column_id INT PRIMARY KEY AUTO_INCREMENT COMMENT '栏目ID',
    column_name VARCHAR(255) NOT NULL COMMENT '栏目名称',
    create_time DATETIME DEFAULT NOW() COMMENT '创建时间',
    update_time DATETIME DEFAULT NOW() ON UPDATE NOW()  COMMENT '更新时间',
    del_status INT DEFAULT 1 COMMENT '1：未删除;0：删除'
    )COMMENT '栏目信息表';


-- 新闻

CREATE TABLE IF NOT EXISTS news_info
(
    news_id INT PRIMARY KEY AUTO_INCREMENT COMMENT '新闻ID',
    column_id INT COMMENT '栏目ID',
    news_title VARCHAR(255) NOT NULL COMMENT '新闻标题',
    news_content TEXT NOT NULL COMMENT '新闻内容',
    create_time DATETIME DEFAULT NOW() COMMENT '创建时间',
    update_time DATETIME DEFAULT NOW() ON UPDATE NOW()  COMMENT '更新时间',
    del_status INT DEFAULT 1 COMMENT '1：未删除;0：删除',
    is_top INT DEFAULT 0 COMMENT '0:不置顶；1：置顶'

    )comment '新闻信息表'
```

## 5、连接数据库

5.1 db.propertis

```properties
user=root
password=123456
url=jdbc:mysql://localhost:3306/shopping?characterEncoding=UTF-8&rewriteBatchedStatements=true
driver=com.mysql.cj.jdbc.Driver

```
5.2 DbConn.java

```java
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.Properties;

public class DbConn {

    public static Connection openConn() throws Exception {
        //加载配置文件
        //加载资源的两种方式
        //1、当前类.class.getClassLoader().getResourceAsStream("资源文件路径");  从根路径找  此时java与resources为根路径
        //2、当前类.class.getResourceAsStream("db.properties");  此时从当前类所在的路径向下找
        //3、此处使用到了java中的I/O流
        InputStream inputStream = DbConn.class.getClassLoader().getResourceAsStream("db.properties");

        Properties properties = new Properties();
        properties.load(inputStream);
        //读取信息
        String user = properties.getProperty("user");
        String password = properties.getProperty("password");
        String url = properties.getProperty("url");
        String driver = properties.getProperty("driver");

        //加载驱动
        Class.forName(driver);
        //获取连接
        Connection connection = DriverManager.getConnection(url,user,password);
        return connection;
    }
}

```



## 6、创建`UserInfo.java`

```java
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

import java.util.Date;

@Data
@NoArgsConstructor
@AllArgsConstructor
@ToString
public class UserInfo {
    private int userId;
    private String userName;
    private String userPwd;
    private int userAge;
    private String userSex;
    private Date createTime;
    private Date updateTime;
    private int delStatus;
}
```

## 7、操作UserInfo  `UserInfoDao`

```java
import com.newcapec.entity.UserInfo;
import com.newcapec.utils.DbConn;
import com.sun.org.apache.regexp.internal.RE;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

public class UserInfoDao {

    public static UserInfo login(String userName,String userPwd) throws Exception {
        UserInfo userInfo = null;
        Connection connection = DbConn.openConn();
        String sql = "select * from user_info where user_name = ? and user_pwd = ?";
        PreparedStatement statement = connection.prepareStatement(sql);
        statement.setString(1,userName);
        statement.setString(2,userPwd);
        ResultSet resultSet = statement.executeQuery();
        while(resultSet.next()){
            int userId = resultSet.getInt("user_id");
//            String userName = resultSet.getString("user_name");
//            String userPwd = resultSet.getString("user_pwd");
            int userAge = resultSet.getInt("user_age");
            String userSex = resultSet.getString("user_sex");
            Date createTime = resultSet.getTimestamp("create_time");
            Date updateTime = resultSet.getTimestamp("update_time");
            int delStatus = resultSet.getInt("del_status");
            userInfo = new UserInfo(userId,userName,userPwd,userAge,userSex,createTime,updateTime,delStatus);

        }
        resultSet.close();
        statement.close();
        connection.close();
        return userInfo;
    }

    public static List<UserInfo> selectAll() throws Exception {
        List<UserInfo> userInfos = new ArrayList<>();
        Connection connection = DbConn.openConn();
        String sql = "select * from user_info";
        PreparedStatement statement = connection.prepareStatement(sql);
        ResultSet resultSet = statement.executeQuery();
        while(resultSet.next()){
            int userId = resultSet.getInt("user_id");
            String userName = resultSet.getString("user_name");
            String userPwd = resultSet.getString("user_pwd");
            int userAge = resultSet.getInt("user_age");
            String userSex = resultSet.getString("user_sex");
            Date createTime = resultSet.getTimestamp("create_time");
            Date updateTime = resultSet.getTimestamp("update_time");
            int delStatus = resultSet.getInt("del_status");
            UserInfo userInfo = new UserInfo(userId,userName,userPwd,userAge,userSex,createTime,updateTime,delStatus);
            userInfos.add(userInfo);
        }
        resultSet.close();
        statement.close();
        connection.close();
        return userInfos;
    }

    public static boolean insert(UserInfo userInfo) throws Exception {
        boolean flag = false;
        Connection connection = DbConn.openConn();
        String sql = "insert into user_info (user_name,user_pwd,user_sex,user_age) values (?,?,?,?)";
        PreparedStatement statement = connection.prepareStatement(sql);
        statement.setString(1,userInfo.getUserName());
        statement.setString(2,userInfo.getUserPwd());
        statement.setString(3,userInfo.getUserSex());
        statement.setInt(4,userInfo.getUserAge());
        int count = statement.executeUpdate();
        if(count>0){
            flag = true;
        }
        statement.close();
        connection.close();
        return flag;
    }
}

```

## 8、统一数据返回格式

```java
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;

@Data
@NoArgsConstructor
@AllArgsConstructor
@ToString
public class Result<T>{
    private int code;  //200表示成功
    private String msg; //结果信息
    private T data; //结果数据
}
```

## 9、JSON讲解

分为简单数据与键值对

```
"张三"

20
```

对象

```json
{
    //一个个的键值对
    name:"张三",
    age:20,
    teacher:{
        name:"teacher1",
        sex:"男"
    }
}
```

数组

```json
[
    //一个个的键值对
    name:"张三",
    children:[
    	{name:"张三"}
	]
]
```

# 三、前端

1、引入layui

2、

## 3、添加流程
1、点击添加按钮，展示添加模态框,如果是更新按钮，会增加自动填充数据的步骤
```js
function showEditModel() {
	//判断是否有被选中的项，并且只能有一项被选中
	var checkStatus = layui.table.checkStatus('userInfoTable'); //idTest 即为基础参数 id 对应的值
	console.log(checkStatus.data) //获取选中行的数据
	console.log(checkStatus.data.length) //获取选中行数量，可作为是否有选中行的条件
	var length = checkStatus.data.length;
	if (length == 0) {
		//layui.layer.alert('请选择要编辑的条目');
		layui.layer.msg("请选择要编辑的条目");
	}
	if (length > 0) {
		//layui.layer.alert('请选择一条数据');
		layui.layer.msg("请选择一条数据");
	}
	if (length == 1) {
		//layui.layer.alert('准备编辑');
		layui.layer.msg("准备编辑");
		//编辑和添加可以复用一个模态框
		showAddModel();
		//数据填充进去
		var userInfoData = checkStatus.data[0];
		//layui.$("input[name='userName']").val(userInfoData.userName);
		inutEditModel(userInfoData);
	}
}

function inutEditModel(data){
	layui.$("#userId").val(data.userId);
	layui.$("input[name='userName']").val(data.userName);
	layui.$("input[name='userPwd']").val(data.userPwd);
	layui.$("input[name='userAge']").val(data.userAge);
	if(data.userSex == '男'){
		layui.$("input[value='男']").prop("checked","true");
	}

	if(data.userSex == "女"){
		layui.$("input[value='女']").prop("checked","true");
	}

	if(data.delStatus == 1){
		layui.$("input[title='不删除']").prop("checked","true");
	}
	if(data.delStatus == 0){
		layui.$("input[title='删除']").prop("checked","true");
	}
	layui.form.render();
	//layui.$("input[name='userName']").val(userInfoData.username);
}

```
2、填写数据
3、点击提交按钮
    3.1 首先验证表单数据是否符合要求
```js
layui.form.verify({
	username: function(value, item) { //value：表单的值、item：表单的DOM对象
		if (value.length < 5) {
			return '用户名长度不能小于5';
		}
	},
	password: function(value, item) { //value：表单的值、item：表单的DOM对象
		if (value.length <= 0) {
			return '密码不能为空';
		}
	}
});
```
3.2 验证完成后表单拦截异步提交,在异步提交时根据userId是否为空判断是应该添加还是更新
```js
/*拦截表单提交，改为异步*/
layui.form.on('submit(submitUser)', function(data) {
	//手动发起异步请求 ajax
	console.log(data.field);
	if(data.field.userId != ""){
		posturl = "../updateUser";
	}else{
		posturl = "../useradd";
	}
	//ajax是jquery中的异步请求框架
	//layui中已经集成的有jquery框架
	//layui.$去使用
	layui.$.ajax({
		type: "POST",
		url: posturl,
		data: data.field,
		success: function(result) {
			if(result.code == 200){
				layui.layer.alert(result.msg, {icon: 1});
				//重新加载数据
				layui.table.reload("userInfoTable");
			}
			if(result.code == 500){
				layui.layer.alert(result.msg, {icon: 2});
			}
		}
	});
	closeAddModel();
	return false; //阻止表单跳转。如果需要表单跳转，去掉这段即可。
});
```
3.3 提交后自动出发清除表单事件
```js
function clearAddModelInfo() {
	layui.$("#userId").val();
	layui.$("input[name='userName']").val("");
	layui.$("input[name='userPwd']").val("");
	layui.$("input[name='verify']").val("");
	layui.$("input[name='userAge']").val("");
	layui.$("input[value='男']").prop("checked","true");
	//让表单重新渲染，才能使	layui.$("input[value='男']").prop("checked","true");生效
	layui.form.render();
}
```
3.4 根据返回的json数据的Code值做判断

```js
$.ajax({
  url: "/xxx",
  type: "GET",
  data: {
    "boxIds": boxIds,
    "boxType": 0,
    "time": new Date().getTime()
  },
  traditional: true,//这里设置为true
  success: function(data) {
    //do sth...
  }
});
```

## AJAX异步请求
>Http协议
>
***可以提高页面响应效率***