How to merge cells (or apply colspan) using XWPFTable in POI in Java?

apache-poi, java, xwpf

Solution

To merge horizontally/vertically you need to create 2 CTHMerge and use the setVal:

- one for the cells that you will remain (STMerge.RESTART);

- a second one for the merged cells (STMerge.CONTINUE);

a) example for a horizontal merge for 2x2 table (image with example):

||| --> |___________ | ||| --> | ___________|

 // First Row
CTHMerge hMerge = CTHMerge.Factory.newInstance();
hMerge.setVal(STMerge.RESTART);
table.getRow(0).getCell(0).getCTTc().getTcPr().setHMerge(hMerge);
table.getRow(1).getCell(0).getCTTc().getTcPr().setHMerge(hMerge);

 // Secound Row cell will be merged/"deleted"
CTHMerge hMerge1 = CTHMerge.Factory.newInstance();
hMerge1.setVal(STMerge.CONTINUE);
table.getRow(0).getCell(1).getCTTc().getTcPr().setHMerge(hMerge1);
table.getRow(1).getCell(1).getCTTc().getTcPr().setHMerge(hMerge1);

b) example of a vertical merge (image with example)

 // First Row
CTVMerge vmerge = CTVMerge.Factory.newInstance();
vmerge.setVal(STMerge.RESTART);
table.getRow(0).getCell(0).getCTTc().getTcPr().setVMerge(vmerge);
table.getRow(0).getCell(1).getCTTc().getTcPr().setVMerge(vmerge);
 
 // Secound Row cell will be merged 
CTVMerge vmerge1 = CTVMerge.Factory.newInstance();
vmerge1.setVal(STMerge.CONTINUE);
table.getRow(1).getCell(0).getCTTc().getTcPr().setVMerge(vmerge1);
table.getRow(1).getCell(1).getCTTc().getTcPr().setVMerge(vmerge1);

Problem

Creating a table in poi was quite easy but it has very limited tutorials and I cannot find one that can create a simple merged cell in a table in generating a docx file.

Original source