java写数据接口

天天_哥

发布于 2018-09-29 14:50:57

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发布于 2018-09-29 14:50:57

文章被收录于专栏：天天天天

1.新建DynamicWeb项目

其中要用到的 gson此处用于将持久化对象解析为Json，或将Json序列化为对象。

==目录如下==

主要是使用到下边红框中的类

1.1 基础数据对象

package cn.hy.newsTest;

import java.util.Date;

public class News {
    private int nId; // 新闻ID
    private String title; // 新闻标题
    private String content; // 新闻内容
    private String date; // 新闻发布日期
    private String url; //新闻地址
    private Date nDate; // 新闻日期，Date类型
    
    
    public int getnId() {
        return nId;
    }

    public void setnId(int nId) {
        this.nId = nId;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }

    public String getDate() {
        return date;
    }

    public void setDate(String date) {
        this.date = date;
    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public Date getnDate() {
        return nDate;
    }

    public void setnDate(Date nDate) {
        this.nDate = nDate;
    }

 
    public News(int nId, String title, String content, String date, String url) {
        this.nId = nId;
        this.title = title;
        this.content = content;
        this.date = date;
        this.url = url;
    }

}

1.2 对返回的接口数据封装类

package cn.hy.newsTest;

import java.util.List;

public class NewsList {
    private int total; //新闻数量
    private List<News> rows; //新闻列表
    
    
    public int getTotal() {
        return total;
    }
    public void setTotal(int total) {
        this.total = total;
    }
    public List<News> getRows() {
        return rows;
    }
    public void setRows(List<News> rows) {
        this.rows = rows;
    }
    public NewsList() {}
    public NewsList(int total, List<News> rows) {
        this.total = total;
        this.rows = rows;
    }
}

1.3数据库数据

1.4新建servlet类

package cn.hy.newsTest;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanListHandler;

import com.google.gson.Gson;

import java.io.PrintWriter;
import java.sql.*;
import java.util.List;
 
public class JsonServlet2 extends HttpServlet {
 
    private static final long serialVersionUID = 1L;

    @Override
         protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
             try {
                 QueryRunner runner = new QueryRunner(C3P0Utils.getDataSource());
                 String sql = "SELECT * FROM news";
                 List<News> newsList = runner.query(sql, new BeanListHandler<News>(News.class));
                
                // 将数据封装到新闻总计类
                NewsTotal nt = new NewsTotal(newsList.size(), newsList);
          
                // 调用GSON jar工具包封装好的toJson方法，可直接生成JSON字符串
                Gson gson = new Gson();
                String json = gson.toJson(nt);
          
                // 输出到界面
                System.out.println(json);
                resp.setContentType("text/plain");
                resp.setCharacterEncoding("gb2312");
                PrintWriter out = new PrintWriter(resp.getOutputStream());
                out.print(json);
                out.flush();
                // 更多Json转换使用请看JsonTest类
               } catch (SQLException e) {
                   e.printStackTrace();
               } 
               
           }
       
           @Override
           protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
               doGet(req, resp);
           }
 
}

发布项目，在tomcat访问JsonServlet,最后在浏览器就能拿到数据