先繪制壹個最簡單的Echarts圖表:
(這裏就直接貼上代碼了,直接用的是官網教程裏異步數據加載和更新裏的代碼)
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "/下載 jackson-core.jar,jackson-annotations.jar,jackson-databind.jar(都是2.x版本,jackson官網不知為何不提供服務了…這三個jar讓我壹陣好找)
②:在項目的項目WEB-INF/lib下引入這三個jar
然後就可以在TestServlet裏使用jackson提供的工具類了。(關於jackson的詳細用法,這裏貼壹下官網教程:/JacksonInFiveMinutes)
TestServlet代碼如下:
package test;
import java.io.IOException;
import java.util.*;
import javax.servlet.ServletException;
import javax.servlet..fasterxml.jackson.databind.ObjectMapper;
public class TestServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req,resp);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
List<Product> list = new ArrayList<Product>();
//這裏把“類別名稱”和“銷量”作為兩個屬性封裝在壹個Product類裏,每個Product類的對象都可以看作是壹個類別(X軸坐標值)與銷量(Y軸坐標值)的集合
list.add(new Product("襯衣", 10));
list.add(new Product("短袖", 20));
list.add(new Product("大衣", 30));
ObjectMapper mapper = new ObjectMapper(); //提供java-json相互轉換功能的類
String json = mapper.writeValueAsString(list); //將list中的對象轉換為Json格式的數組
//System.out.println(json);
//將json數據返回給客戶端
response.setContentType("text/html; charset=utf-8");
response.getWriter().write(json);
}
TestServlet類中用到的自定義的Product類代碼如下:
package test;
public class Product {
private String name; //類別名稱
private int num; //銷量
public Product(String name, int num) {
this.name = name;
this.num = num;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getNum() {
return num;
}
public void setNum(int num) {
this.num = num;
}
}
4.客戶端接收數據後顯示
客戶端接受服務器數據並解析後,就可以正常顯示圖表數據了: